WO2020196400A1 - Zirconia microparticulate material, catalyst for gas treatment use, and method for producing same - Google Patents

Zirconia microparticulate material, catalyst for gas treatment use, and method for producing same Download PDF

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WO2020196400A1
WO2020196400A1 PCT/JP2020/012706 JP2020012706W WO2020196400A1 WO 2020196400 A1 WO2020196400 A1 WO 2020196400A1 JP 2020012706 W JP2020012706 W JP 2020012706W WO 2020196400 A1 WO2020196400 A1 WO 2020196400A1
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zirconia
fine particle
particle material
zirconia fine
particles
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PCT/JP2020/012706
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French (fr)
Japanese (ja)
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正邦 小澤
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国立大学法人東海国立大学機構
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Priority to JP2021509390A priority Critical patent/JP7188822B2/en
Publication of WO2020196400A1 publication Critical patent/WO2020196400A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
    • B01D53/94—Chemical or biological purification of waste gases of engine exhaust gases by catalytic processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B01J23/46—Ruthenium, rhodium, osmium or iridium
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G25/00—Compounds of zirconium
    • C01G25/02—Oxides

Definitions

  • the present invention relates to a zirconia fine particle material used as a catalyst carrier and the like and a method for producing the same.
  • zirconium oxide hereinafter, also referred to as "zirconia”
  • its powder have been used in the fields of high-strength materials, electronic devices, fuel cell materials, functional ceramics, catalyst materials, and the like. Recently, it has become important to use it as a carrier for a catalyst for gas treatment such as an automobile exhaust gas purification catalyst, and an atomized pure zirconia material or the like is required.
  • zirconia As a method for producing zirconia, the precipitation method is widely used mainly from the viewpoints of purity, particle size miniaturization and homogenization, and mass productivity.
  • zirconia causes a phase transition as it is, it is often used in a state where a rare earth element is added.
  • ultrafine particles there has been a demand for ultrafine particles, and it is difficult to stabilize the zirconia fine particles and to be in the nanoparticle state. Therefore, various methods as described below have been developed. Proposed.
  • Patent Document 1 discloses a method for producing a high-purity zirconia-based colloid sol by hydrolyzing a zirconium salt, an yttrium salt, or the like and then passing the zirconium salt through a filtration membrane.
  • Patent Document 2 discloses a method for producing a tetragonal or cubic zirconia sol by heat-aging a zirconium salt and a base such as a calcium salt.
  • Patent Document 3 nanoparticles formed by solid-dissolving an alkaline earth metal oxide in zirconia are heated to 400 ° C. or higher by setting the pH of the raw material salt mixture aqueous solution to 7 or higher to form a precipitate, and the alkaline soil is described.
  • a method for producing metal oxide-doped zirconia square nanoparticles is disclosed.
  • any of Sc, Y, and Yb is added, and fine particles having an average particle diameter of 10 nm or less and having a tetragonal crystal phase of stabilized zirconia are subcritical or subcritical.
  • a production method for producing water in a supercritical state as a medium is disclosed.
  • additive-free zirconia nanoparticles single crystal zirconia nanoparticles without addition of other elements.
  • additive-free zirconia nanoparticles monoclinic crystals of additive-free zirconia nanoparticles are stable at 900 ° C. or lower, and several methods as shown below have been developed as methods for obtaining such additive-free zirconia nanoparticles.
  • Patent Document 5 inorganic fine particles having an average particle size of 1 nm to 30 nm of primary particles are present in a solvent in an agglomerated state, and a mixed solution containing a metal alkoxide is supplied to a dispersion container of a dispersion device to disperse the particles.
  • a method for producing an inorganic fine particle dispersion solution comprises stirring the particles in a container using beads having a size of 15 ⁇ m to 30 ⁇ m and simultaneously applying ultrasonic waves to the dispersion container to disperse the inorganic fine particles.
  • Patent Document 6 discloses surface-modified monoclinic zirconia particles, and has developed a technique capable of producing them under hydrothermal conditions at 250 to 400 ° C. According to the examples, when tetragonal zirconia is formed, the particle size is remarkably increased and the nanoparticle state is not maintained, which is not suitable for use.
  • Patent Document 7 includes zirconia nanoparticles comprising a step of heating a raw material solution containing a metal salt hydrate, an acid, and a solvent at a temperature below the critical temperature of a compound containing a hydroxyl group produced by decomposition of the solvent under pressure. The manufacturing method of the above was disclosed, and the crystal phase was monoclinic from the XRD diagram.
  • Patent Document 8 describes a zirconia transparent dispersion liquid containing zirconia particles and a dispersion medium, wherein the zirconia particles are tetragonal zirconia particles having a dispersion particle size of 1 nm to 20 nm.
  • a transparent composite characterized in that the liquid and the tetragonal zirconia particles are dispersed in a resin.
  • the method for producing the transparent dispersion is disclosed only in Examples, and the slurry is prepared by adding aqueous ammonia to the solution of zirconium oxychloride with stirring, and the aqueous solution of sodium sulfate is added with stirring, and then the mixture is added to a dryer.
  • Patent Document 9 discloses a zirconium oxide nanoparticles containing tetragonal zirconium oxide coated with two or more kinds of coating agents, and a coating composition containing the zirconium oxide nanoparticles.
  • a coating agent-zirconium composite in advance from at least a zirconium oxide precursor and a specific coating agent, zirconium oxide nanoparticles are subjected to a hydrothermal reaction under relatively mild conditions of less than 1 MPaG. It is disclosed that can be synthesized.
  • tetragonal additive-free zirconia can be obtained, and zirconia undergoes phase transformation into monoclinic crystals at low temperatures and into tetragonal or cubic crystals as the temperature rises. Therefore, the tetragonal crystal is stable at around 1200 ° C.
  • tetragonal crystals are generated as metastable phases as aggregates of fine particles by the precipitation method, etc., when the aggregation is strong, and they are transformed into stable monoclinic crystals as the particles become coarser due to heating or the like. ing.
  • nanoparticles are constrained in the solidified body at the time of fine particle synthesis such as the sol-gel method, or exist as polycrystalline particles strongly aggregated at the time of crystallization, and further in the agglomerates fired at a low temperature. That is, it can be considered that tetragonal zirconia is difficult to be produced as a single nanoparticle crystal.
  • Patent Document 8 discloses a manufacturing method that requires a complicated and multi-step processing process in order to deal with this difficulty in production.
  • a dispersed particle size of 7 nm was obtained, but depending on the treatment of mixing the calcined powder of the nanoparticles produced in the same manner as described in the solvent together with a commercially available dispersant, only some of the particles are contained in the solvent.
  • the yield of obtaining zirconia nanoparticles is low because many of them remain agglomerated without being dispersed in the solvent. Furthermore, it is easily presumed that it is difficult to maintain a single crystal due to aggregation during firing as to whether the particles are single crystal.
  • Patent Document 9 discloses a method using a hydrothermal method.
  • the treatment temperature is 180 ° C. or lower
  • high-temperature heating is required as in the examples where the temperature is 180 ° C. or lower.
  • it since it has a step of removing coarse particles by filtration for removing the precipitate of zirconia particles, it takes a lot of time and equipment to select such fine particles.
  • the nano-level size fine particles as shown in the background technology are very small, so the knowledge about their morphology is unknown.
  • attention has been paid to the effects of peculiar morphology and attention has been paid to the generation of morphology such as rods and nanosheets, and complex shapes such as petals.
  • morphology such as rods and nanosheets
  • complex shapes such as petals.
  • fine particles as a catalyst, an adsorbent, and a carrier.
  • tetragonal zirconia single crystal fine particles and their dispersions are useful as catalyst carriers and ceramic precursors effective for gas treatment, they are difficult to obtain as nano-level single crystal particles, so these applications The use of tetragonal zirconia was hindered.
  • Monodisperse, single crystal nano-sized tetragonal zirconia particles can be used as raw materials that can be arranged for devices, as adsorbents and catalyst materials that are all exposed as a surface without loss at the neck, and as a molded product. It is expected to be a material that can be applied in a wide range, such as as a filler for.
  • pure zirconia fine particles and a dispersion thereof are difficult to obtain as nano-level particles, although they are useful as catalyst carriers and ceramic precursors effective for gas treatment.
  • the active site appears specifically, and when it becomes a nanosheet shape, it is expected that the particle itself has anisotropy specificity.
  • nanosheets are placed on the substrate, the use of ultra-thin film materials will expand. If zirconia particles having such a peculiar shape can be produced, it is expected as a material that can be applied as a raw material that can be arranged for a device.
  • An object of the present invention is to provide such single crystal tetragonal additive-free zirconia nanoparticles, a simple method for producing the same, and a method for using the same as a catalyst material.
  • Another object of the present invention is to provide zirconia fine particles having a complicated shape or nanosheets as crystals of single nanoparticles, a simple method for producing the same, and a method for using the zirconia as a catalyst material.
  • the present inventor has produced a zirconia fine particle material having a monoclinic zirconia crystal phase content of 10% or less, an average particle size of 20 nm or less, and a single crystal ratio of 90% or more. I succeeded in getting it.
  • this zirconia fine particle material for example, a simple treatment of neutralizing an aqueous solution containing a zirconium salt to obtain a precipitate and conducting a hydrothermal reaction under mild conditions is performed to obtain a single crystal nano of square zirconia.
  • the present inventor is a monoclinic zirconia fine particle material in which the proportion of tetragonal crystals containing 100% of the total crystal phase is 20% or less, and the proportion of particles having a particle size of 5 to 30 nm is 60% or more. Succeeded in getting.
  • This zirconia fine particle material has a unique shape of monoclinic zirconia by, for example, subjecting a simple treatment of neutralizing an aqueous solution containing a zirconium salt to obtain a precipitate and conducting a hydrothermal reaction under milder conditions.
  • Item 1 It is a zirconia fine particle material and has the following (1) or (2): (1) The proportion of monoclinic crystals containing 100% of the total crystal phase is 10% or less. The average particle size is 20 nm or less, and It is a tetragonal zirconia fine particle material in which the proportion of single crystals containing 100% of all crystals is 90% or more, or (2) the proportion of tetragonal crystals containing 100% of all crystal phases is 20% or less. , A monoclinic zirconia fine particle material having an average particle size of 5 to 30 nm. Zirconia fine particle material that meets any of the above.
  • Item 2 The zirconia fine particle material according to Item 1, which satisfies the above (1).
  • Item 3 The zirconia fine particle material according to Item 2, wherein the proportion of monoclinic crystals containing 100% of the total crystal phase is 5% or less.
  • Item 4 The zirconia fine particle material according to Item 2 or 3, wherein the average particle size is 0.1 to 10 nm.
  • Item 5 The zirconia fine particle material according to any one of Items 2 to 4, wherein the average particle size is 0.2 to 5 nm.
  • Item 6 The zirconia fine particle material according to any one of Items 2 to 5, wherein the ratio of the single crystal contained is 95% or more.
  • Item 7 The zirconia fine particle material according to Item 1, which satisfies the above (2).
  • Item 8 The zirconia fine particle material according to Item 7, wherein the ratio of the sheet-like material having a thickness of 3 nm or less is 50% or more, where the total number of particles is 100%.
  • Item 9 The monoclinic zirconia fine particle material according to Item 7 or 8, wherein the proportion of particles having an amorphous shape is 60% or more, where the total number of particles is 100%.
  • Item 10 The zirconia fine particle material according to any one of Items 7 to 9, wherein the proportion of particles having a shape in which a plurality of protrusions extend in irregular directions is 50% or more, assuming that the total number of particles is 100%.
  • Item 11 A catalyst for gas treatment containing the zirconia fine particle material according to any one of Items 1 to 10.
  • Item 12 At least one selected from the group consisting of a metal selected from Pt, Pd, Rh, Au, Cu, Fe, Ni, Ag and Ce, an alloy containing the metal, and an oxide of the metal in the zirconia fine particle material.
  • a metal selected from Pt, Pd, Rh, Au, Cu, Fe, Ni, Ag and Ce, an alloy containing the metal, and an oxide of the metal in the zirconia fine particle material.
  • Item 13 An aqueous solution or a colloidal solution containing the tetragonal zirconia fine particle material according to any one of Items 1 to 10 or the gas treatment catalyst according to Item 11 or 12.
  • Item 14 The zirconia nanosheet material containing the zirconia fine particle material according to any one of Items 7 to 10 or the gas treatment catalyst according to Item 11 or 12.
  • Item 15 The method for producing a zirconia fine particle material according to any one of Items 2 to 6, the gas treatment catalyst according to Item 11 or 12, or the aqueous solution or colloidal solution according to Item 13.
  • the first step of obtaining a precipitate-containing aqueous solution by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline.
  • the second step of heating the precipitate-containing aqueous solution at 90 ° C. to 170 ° C. A manufacturing method.
  • Item 16 The production method according to Item 15, wherein the heating holding time in the second step is 10 minutes or more and 24 hours or less.
  • Item 17. Monoclinic zirconia fine particle material according to any one of Items 7 to 10, gas treatment catalyst according to Item 11 or 12, aqueous solution or colloidal solution according to Item 13, or zirconia nanosheet material according to Item 14. It is a manufacturing method of The first step of obtaining a precipitate-containing aqueous solution by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline. The second step of heating the precipitate-containing aqueous solution at 180 ° C. to 600 ° C. for 12 hours or more, and A manufacturing method.
  • Item 19 The production method according to any one of Items 15 to 18, wherein the zirconia fine particle material or the catalyst for gas treatment is obtained by removing the solvent of the solution after the second step or the third step.
  • Item 20 The production method according to any one of Items 15 to 18, wherein after the second step or the third step, the zirconia nanosheet material is obtained by adding a solution onto a substrate or immersing the substrate in the solution and taking it out.
  • the tetragonal zirconia fine particle material of the present invention is a single crystal tetragonal additive-free zirconia nanoparticles, and is used as a catalyst carrier or a ceramic raw material effective for the development of a catalyst material to bring about particularly high activity and gas treatment. It is useful and can greatly expand the scope of application of tetragonal nanoparticles zirconia. Further, in the monoclinic zirconia fine particle material of the present invention, the proportion of tetragonal crystals containing 100% of the total crystal phase is 20% or less, and the proportion of particles having a particle size of 5 to 30 nm is 60% or more.
  • the monoclinic zirconia fine particle material of the present invention can be a sheet-like material having a thickness of 3 nm or less, or particles having an irregular shape.
  • This monoclinic zirconia fine particle material is particularly useful as a catalyst carrier and a ceramic raw material effective for the development of a catalyst material that is intended to bring about high activity and gas treatment, and greatly expands the range of application of the specific form of nanoparticle zirconia. Can be expanded to.
  • 5 is an X-ray diffraction pattern of the zirconia fine particle material of Examples 1 to 4 and Comparative Example 1.
  • 5 is an X-ray diffraction pattern of the zirconia fine particle material (after firing at 600 ° C.) of Examples 1 to 4 and Comparative Example 1.
  • 6 is an X-ray diffraction pattern of the monoclinic zirconia fine particle material (200 ° C.) of the present invention (Examples 12 and 13). It is a transmission electron microscope image in a solid state of the monoclinic zirconia fine particle material (200 degreeC 48 hours) of this invention (Example 13). It is a particle size distribution in the solid state of the monoclinic zirconia fine particle material (200 ° C.
  • Example 13 It is an atomic force microscope image and a height measurement result in a solid state after supporting the zirconia nanoparticle material (200 degreeC 48 hours) of this invention (Example 14) on a Si single crystal plate.
  • the zirconia fine particle material of the present invention has the following (1) or (2): (1) The proportion of monoclinic crystals containing 100% of the total crystal phase is 10% or less. The average particle size is 20 nm or less, and It is a tetragonal zirconia fine particle material in which the proportion of single crystals containing 100% of all crystals is 90% or more, or (2) the proportion of tetragonal crystals containing 100% of all crystal phases is 20% or less. , A monoclinic zirconia fine particle material having an average particle size of 5 to 30 nm. Satisfy either.
  • the present invention is a tetragonal zirconia fine particle material in which the proportion of monoclinic crystals containing 100% of the total crystal phase is 10% or less. It is a tetragonal zirconia fine particle material having an average particle size of 20 nm or less and a ratio of single crystals of 90% or more with all crystals as 100%.
  • the tetragonal zirconia fine particle material of the present invention can be zirconia fine particles having tetragonal crystals without positively adding other elements (elements other than zirconium and oxygen). It does not matter whether the tetragonal zirconia fine particle material of the present invention has a tetragonal crystal or a crystal having different atomic displacements in the tetragonal crystal, or has a defect and the defect is distributed in a disordered or ordered manner. Since the tetragonal zirconia fine particle material of the present invention is a particularly small crystal having an average particle diameter of 20 nm or less, it is expected that the relationship between the temperature and the phase of the so-called conventional large single crystal or fired ceramics will not be established.
  • zirconia has the following structural phase transitions. That is, it changes from a monoclinic crystal stable at room temperature to a tetragonal crystal at about 1170 ° C. and further to a cubic crystal at about 2200 ° C. Further, when there is a tetragonal crystal as a metastable phase at room temperature, it is said that it changes to a monoclinic crystal due to a non-diffusion type phase transition induced by stress or the like. It is considered that there has been no example of cubic crystals formed by comparatively pure ZrO 2 near room temperature.
  • the correct expression is when it is cubic, and when it is larger than 1, it is tetragonal. Also, a tetragonal crystal that considers only the displacement of oxygen can be considered.
  • the particle size of the material is extremely small to the extent that it has not been known so far, and it is a fact that it is more difficult to measure c / a.
  • the tetragonal zirconia fine particle material of the present invention has a monoclinic crystal abundance ratio of 10% or less (0 to 10%), preferably 5% or less (0 to 5%), with the total crystal phase as 100%. If the abundance ratio of monoclinic crystals exceeds 10%, sufficient catalytic activity cannot be obtained. Therefore, in the tetragonal zirconia fine particle material of the present invention, the abundance ratio of tetragonal crystals is preferably 90% or more (90 to 100%), more preferably 95% or more (95 to 100%), with the total crystal phase as 100%. preferable.
  • the abundance ratio of monoclinic crystals of 10% or less means that among the tetragonal zirconia fine particle materials, there are very few phases having a stable structure near room temperature.
  • the abundance ratio of monoclinic crystals is preferably 10% or less (particularly 5% or less), and the abundance ratio of tetragonal crystals is 90. % Or more (particularly 95% or more) is preferable.
  • the tetragonal zirconia fine particle material of the present invention has an average particle diameter of 20 nm or less, preferably 0.1 to 10 nm, and more preferably 0.2 to 5 nm. If the average particle size exceeds 20 nm, it cannot be sufficiently miniaturized and sufficient catalytic activity cannot be obtained. Similarly, in the tetragonal zirconia fine particle material of the present invention, the abundance ratio of the particle diameter of 10 nm or less is preferably 90% or more (90 to 100%), and the abundance ratio of the particle diameter of 5 nm or less is 95%. The above (95 to 100%) is preferable.
  • the proportion of single crystals containing 100% of all crystals is 90% or more (90 to 100%), preferably 95% or more (95 to 100%). If the proportion of single crystals is less than 90%, the proportion of single crystals is small and sufficient catalytic activity cannot be obtained. Further, the fact that the fine particle material has an average particle diameter of 20 nm or less and a single crystal abundance ratio of 90% or more can be directly determined by examining the particle size by a transmission electron microscope in a solid state. To determine. Each particle exists in an independent state, and if the particle size is measured, it can be determined that the particle is a single crystal.
  • the crystallite diameter measured by X-ray diffraction is referred to, but if the particles in electron microscopy match the crystallite diameter in independent size, then these independent particles are single crystals. You may recognize that there is.
  • the dispersion state is determined by the dynamic light scattering method using the Zetasizer Nano S manufactured by Malvern, and the average particle size is calculated.
  • the average particle size means the average area length average diameter calculated from the circle equivalent diameter of each particle using imageJ in the electron microscope image in the solid state, and is found in the colloid in the solution. Is the diameter equivalent to the diffusion coefficient calculated by the dynamic light scattering method, and means the average particle diameter measured by the scattered light intensity standard. The particle shape is clearly observed only by an electron microscope, and it is unavoidable that there is a slight difference depending on the method of measuring the average particle size.
  • the tetragonal zirconia fine particle material of the present invention can be obtained in a state of not containing another element (elements other than zirconium and oxygen) by the production method described later. That is, the tetragonal zirconia fine particle material of the present invention can also be additive-free zirconia nanoparticles containing no other element.
  • the tetragonal zirconia fine particle material of the present invention can also contain an impurity element.
  • the square zirconia fine particle material of the present invention is a metal other than zirconia, for example, a noble metal such as platinum, rhodium, palladium, gold, silver; a transition metal such as Cu, Fe, Ni; a rare earth element; an alkaline earth. It may contain one kind or two or more kinds of metals such as metal.
  • rare earth metals include ytterbium, scandium, lantern, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and the like.
  • precious metals, transition metals, lanthanum (La), neodymium (Nd), praseodymium (Pr), yttrium (Y), etc. coexist with zirconia particles alone or in a mixed state. It is more preferable to include.
  • the content thereof is preferably 2% by mass or less, with the total amount of the tetragonal zirconia fine particle material of the present invention being 100% by mass.
  • the form of the tetragonal zirconia fine particle material of the present invention described above is not particularly limited and may be in a powder state, but may be an aqueous solution or a colloidal solution. Specifically, in the production method described later, it can be obtained as an aqueous solution immediately after the hydrothermal reaction, and then as a colloidal solution when dispersed in an organic solvent.
  • the organic solvent that can be used when the colloidal solution is adopted is preferably a non-polar solvent, such as toluene, benzene, petroleum ether, cyclohexane, heptane, dodecane, cyclohexene, mesitylene (1,3,5-trimethylbenzene), ethylbenzene, and jurene (1,3,5-trimethylbenzene). 1,2,4,5-Tetramethylbenzene), diethyl ether and the like. Further, tetrachloromethane, chloroform, chlorobenzene, dichlorobenzene and the like can also be used. Further, a polar solvent may be used, and alcohols such as propanol and ethanol, ketones such as acetone, dimethyl sulfoxide, tetrahydrofuran, dimethylformamide and the like may be used.
  • a non-polar solvent such as toluene, benzene, petroleum ether, cyclohe
  • the concentration of the tetragonal zirconia fine particle material of the present invention is not particularly limited, and is, for example, 0.0001 to 40% by mass, particularly 0.01 to. It can be 10% by mass.
  • the present invention is secondly a monoclinic zirconia fine particle material in which the proportion of square crystals containing 100% of the total crystal phase is 20.
  • the monoclinic zirconia fine particle material of the present invention can be made into zirconia fine particles having monoclinic crystals without actively adding other elements (elements other than zirconium and oxygen), and it is also peculiar to have a sheet shape. It can also have a shape.
  • the monoclinic zirconia fine particle material of the present invention has a tetragonal abundance ratio of 20% or less (0 to 20%), preferably 10% or less (0 to 10%), with the total crystal phase as 100%. If the abundance ratio of tetragonal crystals exceeds 20%, zirconia fine particles having a sheet shape or a peculiar shape expected to have high activity as a catalyst carrier cannot be obtained. Therefore, in the monoclinic zirconia fine particle material of the present invention, the abundance ratio of monoclinic crystals is preferably 80% or more (80 to 100%), and 90% or more (90 to 100%), with the total crystal phase as 100%. Is more preferable.
  • the abundance ratio of tetragonal crystals is 20% or less means that among the monoclinic zirconia fine particle materials, there are many phases having a stable structure near room temperature.
  • the coexistence of zirconia in different crystalline phases (particularly tetragonal) is explained in the X-ray diffraction pattern.
  • the abundance ratio of tetragonal crystals is preferably 20% or less (particularly 10% or less), and the abundance ratio of monoclinic crystals is 80. % Or more (particularly 90% or more) is preferable.
  • the monoclinic zirconia fine particle material of the present invention has an average particle diameter of 5 to 30 nm, preferably 10 to 25 nm. If the average particle size exceeds 30 nm, it cannot be sufficiently miniaturized and sufficient catalytic activity cannot be obtained. Further, it is difficult to obtain a monoclinic zirconia fine particle material having an average particle diameter of less than 5 nm. Further, the fact that the average particle diameter is 5 to 30 nm is directly determined by examining the particle size by a transmission electron microscope in the solid state. Each particle exists in an independent state, and can be identified by measuring its particle size.
  • the crystallite diameter measured by X-ray diffraction is referred to, but if the particles in electron microscopy match the crystallite diameter in independent size, then these independent particles are single crystals. You may recognize that there is.
  • the dispersion state is determined by the dynamic light scattering method using the Zetasizer Nano S manufactured by Malvern, and the average particle size is calculated. Since the monoclinic zirconia fine particle material of the present invention is a particularly small crystal having an average particle diameter of 5 to 30 nm, it is expected that the relationship between the temperature and the phase of the so-called conventional large single crystal or fired ceramics will not be established. To.
  • the average particle size means the average area length average diameter calculated from the circle equivalent diameter of each particle using imageJ in the electron microscope image in the solid state, and is found in the colloid in the solution. Is the diameter equivalent to the diffusion coefficient calculated by the dynamic light scattering method, and means the average particle diameter measured by the scattered light intensity standard. The particle shape is clearly observed only by an electron microscope, and it is unavoidable that there is a slight difference depending on the method of measuring the average particle size.
  • the monoclinic zirconia fine particle material of the present invention preferably has a particle size of 5 to 30 nm and an abundance ratio of 60% or more (60 to 100%), more preferably 70% or more (70 to 100%).
  • the abundance ratio of the particle size of 5 to 30 nm is 60% or more, it is easy to be sufficiently finely divided and sufficient catalytic activity can be easily obtained.
  • the fine particle material having a particle diameter of 5 to 30 nm and an abundance ratio of 60% or more is directly determined by examining the particle size by a transmission electron microscope method. Each particle exists in an independent state, and can be identified by measuring its particle size.
  • the crystallite diameter measured by X-ray diffraction is referred to, but if the particles in electron microscopy match the crystallite diameter in independent size, then these independent particles are single crystals. You may recognize that there is.
  • the dispersion state is determined by a dynamic light scattering method using Zetasizer Nano S manufactured by Malvern, and the abundance ratio of a particle size of 5 to 30 nm is 60% or more. To confirm.
  • the monoclinic zirconia fine particle material of the present invention can have a sheet-like shape, and the proportion of the sheet-like material having a thickness of 3 nm or less can be 50% or more (50 to 100%), and the thickness can be set.
  • the proportion of the sheet-like material having a thickness of 2.5 nm or less is preferably 70% or more (70 to 100%).
  • the thickness of the monoclinic zirconia fine particle material of the present invention is evaluated by an atomic force microscope.
  • the proportion of particles having an amorphous shape is 60% or more (particularly 70% or more). That is, it is preferable that the proportion of particles having an irregular shape rather than a fibrous, plate-like, or granular shape is 50% or more (particularly 60% or more).
  • the proportion of particles having a shape in which a plurality of protrusions extend in irregular directions is preferably 50% or more (particularly 60% or more), and the tips of adjacent protrusions and the monoclinic zirconia fine particle material. It is preferable that the proportion of particles in which the angle formed by the straight line connecting the centers is less than 180 degrees is 50% or more (particularly 60% or more).
  • the protrusions do not necessarily have one shape, but may have two or more shapes. Further, the protrusion does not necessarily have to have an elongated shape. More preferably, the proportion of particles having a number of branches of 3 or more is 40% or more (particularly 45% or more) by branching a plurality of protrusions in irregular directions. That is, it is preferable that it has an amoeba-like shape or a shape like a jigsaw puzzle piece.
  • the monoclinic zirconia fine particle material of the present invention can be obtained in a state of not containing another element (elements other than zirconium and oxygen) by the production method described later. That is, the monoclinic zirconia fine particle material of the present invention can also be additive-free zirconia nanoparticles containing no other element.
  • the monoclinic zirconia fine particle material of the present invention may also contain an impurity element.
  • the monoclinic zirconia fine particle material of the present invention is a metal other than zirconia, for example, a precious metal such as platinum, rhodium, palladium, gold, silver; a transition metal such as Cu, Fe, Ni; a rare earth element; an alkaline soil. It may contain one kind or two or more kinds of metals such as a kind metal.
  • rare earth metals include ytterbium, scandium, lantern, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and the like.
  • precious metals, transition metals, lanthanum (La), neodymium (Nd), praseodymium (Pr), yttrium (Y), etc. coexist with zirconia particles alone or in a mixed state. It is more preferable to include.
  • the content thereof is preferably 2% by mass or less, with the total amount of the monoclinic zirconia fine particle material of the present invention being 100% by mass.
  • the form of the monoclinic zirconia fine particle material of the present invention described above is not particularly limited and may be in a powder state, but may be an aqueous solution or a colloidal solution. Specifically, in the production method described later, it can be obtained as an aqueous solution immediately after the hydrothermal reaction, and then as a colloidal solution when dispersed in an organic solvent.
  • the organic solvent that can be used when the colloidal solution is adopted is preferably a non-polar solvent, such as toluene, benzene, petroleum ether, cyclohexane, heptane, dodecane, cyclohexene, mesitylene (1,3,5-trimethylbenzene), ethylbenzene, and jurene (1,3,5-trimethylbenzene). 1,2,4,5-Tetramethylbenzene), diethyl ether and the like. Further, tetrachloromethane, chloroform, chlorobenzene, dichlorobenzene and the like can also be used. Further, a polar solvent may be used, and alcohols such as propanol and ethanol, ketones such as acetone, dimethyl sulfoxide, tetrahydrofuran, dimethylformamide and the like may be used.
  • a non-polar solvent such as toluene, benzene, petroleum ether, cyclohe
  • the concentration of the monoclinic zirconia fine particle material of the present invention is not particularly limited, and is, for example, 0.0001 to 40% by mass, particularly 0. It can be 01 to 10% by mass.
  • the zirconia nanosheet material can also be obtained by adding the aqueous solution or colloidal solution of the monoclinic zirconia fine particle material of the present invention described above onto the substrate or immersing the substrate in the solution and taking it out.
  • the monoclinic zirconia fine particle material of the present invention can have a sheet-like material having a thickness of 3 nm or less of 50% or more, and thus can be a nanosheet material having a thin thickness as a whole. is there.
  • the thickness of the zirconia nanosheet material of the present invention is preferably 0.5 to 50 nm ( ⁇ 0.3 nm), more preferably 0.5 to 5 nm ( ⁇ 0.3 nm).
  • the present invention is, thirdly, a gas treatment catalyst containing the above-mentioned tetragonal zirconia fine particle material or monoclinic zirconia fine particle material.
  • the main use of zirconia is a catalyst carrier, especially an exhaust gas purification catalyst material for automobiles, etc., and the catalyst for gas treatment containing the zirconia fine particle material of the present invention as a carrier is particularly effective.
  • the mode in which the zirconia fine particle material of the present invention is used is not limited to the case where it is used as a catalyst carrier.
  • a known catalyst carrier zirconia, alumina, titania, ceria, zirconia-containing ceria, ceria-added zirconia, ceria zirconia solid solution, etc. to which zirconia, rare earths, etc. are added
  • zirconia fine particle material of the present invention functions as an additive or a coating agent for coating and adhering the carrier of the gas treatment catalyst.
  • the tetragonal zirconia fine particle material of the present invention When the tetragonal zirconia fine particle material of the present invention is used, the tetragonal zirconia has a crystal structure characteristic as compared with the monoclinic zirconia, so that it is easy to maintain a flat surface structure at the atomic level and electronic interaction is easy to occur with respect to the metal catalyst. Works as a good carrier.
  • the monoclinic zirconia fine particle material of the present invention when the zirconia is nanoparticles and has a complicated shape, a site specifically active can be expressed on the surface thereof. Further, in the case of nanosheet-like particles, a particularly active material such as a metal cluster can be uniformly supported on the nanosheet-like particles, and the carrier can be effectively used.
  • the monoclinic crystal Due to the characteristics of the crystal structure, it is easy to maintain a flat surface structure at the atomic level and electronic interaction is easy, and it works as a good carrier for metal catalysts. Furthermore, the monoclinic crystal has a stable structure and is unlikely to change over time for various applications.
  • the zirconia fine particle material of the present invention is used, further, with respect to the zirconia fine particle material, metals such as Pt, Pd, Rh, Au, Cu, Fe, Ni, Ag, and Ce, alloys containing these metals, and these metals
  • metals such as Pt, Pd, Rh, Au, Cu, Fe, Ni, Ag, and Ce, alloys containing these metals, and these metals
  • the gas treatment catalyst carrying one or more of the oxides of the above can be effectively used.
  • it has high performance regarding nitrogen oxide purification using a rhodium metal catalyst supported on zirconia, which is often used for exhaust gas purification of automobiles.
  • the tetragonal zirconia fine particle material of the present invention is tetragonal zirconia particles as described above, and according to the production method of the present invention, they can be obtained as a colloidal solution in which fine particles are dispersed by being composited with an organic substance or the like. it can.
  • Such a production method of the present invention comprises a first step of making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline to obtain a precipitate-containing aqueous solution, and heating the precipitate-containing aqueous solution at 90 ° C to 170 ° C.
  • a second step is provided.
  • the method itself for producing the zirconium salt aqueous solution as a raw material thereof is not particularly limited and is known. Can be used. Described in the method recommended in the present invention, when a mixed aqueous solution of a water-soluble zirconium salt and a water-soluble surfactant is neutralized with a base, the precipitated zirconia can be gelled in water.
  • Examples of the water-soluble zirconium salt include zirconium nitrate, zirconium chloride, zirconium nitrate oxide, zirconium chloride chloride and the like.
  • examples of the base that can be used to make the base alkaline in the present invention include ammonia, urea, sodium hydroxide, potassium hydroxide and the like. A method for producing such a zirconia gel is known, and if zirconium coexists when neutralized to form a precipitate, a zirconium salt aqueous solution may be added to the base, or a base may be added to the zirconium salt aqueous solution. May be good.
  • the properties can be changed by changing the temperature at the time of neutralization, the mixing time at the time of neutralization, and the addition rate, and in any case, it can be used in the present invention.
  • the amount of base to be added can be 1 to 100 mol per 1 mol of water-soluble zirconim
  • the temperature at the time of neutralization can be 0 to 99 ° C.
  • the mixing time at the time of neutralization is 1. It can be from 1 minute to 100 hours
  • the addition rate can be 0.001 to 100 mL / sec.
  • the zirconium salt Before mixing the aqueous solution containing the zirconium salt with the base, it is preferable to mix the zirconium salt with the water-soluble organic agent, and it is preferable to use a so-called surfactant as the water-soluble organic agent.
  • the surfactant include unsaturated fatty acids such as oleic acid, linoleic acid and ruuric acid and salts thereof (alkali metal salts such as sodium salt and potassium salt); and other carboxylic acids include saturated fatty acids and methyl tauric acid.
  • Sulfosuccinic acid and its salts alkali metal salts such as sodium salt and potassium salt); alkylbenzene sulfonic acid and its salts (alkali metal salts such as sodium salt and potassium salt); ⁇ -olefin sulfonic acid (tetradecene sulfonic acid and the like) and their salts.
  • Salts alkali metal salts such as sodium salt and potassium salt
  • alkyl sulfate ester acid, alkyl ether sulfate ester salt, phenyl ether sulfate ester salt, ether sulfate salt, alkyl sulfate salt, ether sulfonate and the like can be mentioned in the molecule.
  • Any organic agent having hydrophilic and hydrophobic functional groups can be widely used. Since these may be realized in a state of being adsorbed on the precipitated inorganic component, it is not necessary to form micelles, and there is no limitation on the concentration of the organic agent added such as the critical micelle concentration.
  • concentration of the organic agent added such as the critical micelle concentration.
  • a wide range of 0.001 to 1000 is applicable in which the ratio of the content of zirconium used in the production of tetragonal zirconia fine particle materials, aqueous solutions and colloidal solutions to the number of organic molecules added when expressed in atomic numbers is 0.001 to 1000.
  • the second step is characterized in that the aqueous solution containing the precipitate that has undergone the first step is placed under hydrothermal conditions, but the conditions are 90 ° C. to 170 ° C., particularly preferably 100 ° C. to 160 ° C.
  • the holding time is not particularly limited, but is preferably 10 minutes or more, more preferably 1 hour or more, and even more preferably 6 hours or more.
  • the holding time is preferably 24 hours or less.
  • the container is preferably made of a material and shape that can withstand naturally generated pressure and temperature, but from the viewpoint of container durability, it is appropriate to use a corrosion-resistant material such as Teflon (registered trademark) for the inner container.
  • the solid content in the aqueous solution obtained in the second step can be separated and then dispersed in an organic solvent.
  • the method for separating the solid content in the aqueous solution obtained in the second step is not particularly limited, but the method for filtering after the centrifugation method, the operation for drying at about 100 ° C. from normal room temperature, and the operation for freezing and placing in vacuum conditions. , It can be made into a solid by performing an operation of replacing it with another medium. At this time, if the nanoparticles are apparently solid in any aspect, the independent crystalline state of the individual nanoparticles is maintained.
  • the organic solvent is preferably a non-polar solvent, preferably toluene, benzene, petroleum ether, cyclohexane, heptane, dodecane, cyclohexene, mesitylene (1,3,5-trimethylbenzene), ethylbenzene, and jurene (1,2,4,5-tetra). Methylbenzene) and the like. Further, tetrachloromethane, chloroform, chlorobenzene, dichlorobenzene and the like can also be used.
  • the square zirconia fine particle material of the present invention and gas treatment using the same are used. Can produce a solvent for use. Further, when the solvent is removed after the third step, the independent crystalline state of the tetragonal zirconia fine particle material of the present invention is maintained, which is more preferable as a method for producing zirconia fine particles.
  • an aqueous solution or colloidal solution containing the monoclinic zirconia fine particle material of the present invention or the monoclinic zirconia fine particle material of the present invention, a nanosheet material containing the monoclinic zirconia fine particle material of the present invention, and a single of the present invention A method for producing a monoclinic zirconia fine particle material will be described.
  • the monoclinic zirconia fine particle material of the present invention is monoclinic zirconia particles as described above, and according to the production method of the present invention, they are combined with an organic substance or the like to obtain a colloidal solution in which the fine particles are dispersed. You can also do it.
  • Such a production method of the present invention comprises a first step of obtaining a precipitate-containing aqueous solution by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline, and the precipitate-containing aqueous solution at 180 ° C. to 600 ° C. 12 A second step of heating for an hour or longer is provided.
  • a known method is used without particular limitation on the method itself for producing the zirconium salt aqueous solution as a raw material. Can be used. Described in the method recommended in the present invention, when a mixed aqueous solution of a water-soluble zirconium salt and a water-soluble surfactant is neutralized with a base, zirconia can be precipitated to form a gel in water.
  • Examples of the water-soluble zirconium salt include zirconium nitrate, zirconium chloride, zirconium nitrate oxide, zirconium chloride chloride and the like.
  • examples of the base that can be used to make the base alkaline in the present invention include ammonia, urea, sodium hydroxide, potassium hydroxide and the like.
  • a method for producing a zirconia gel by this coprecipitation method is known. May be added. Further, the properties can be changed by changing the temperature at the time of neutralization, the mixing time at the time of neutralization, and the addition rate, and in any case, it can be used in the present invention.
  • the amount of base to be added can be 1 to 100 mol per 1 mol of water-soluble zirconim
  • the temperature at the time of neutralization can be 0 to 99 ° C.
  • the mixing time at the time of neutralization is 1. It can be from 1 minute to 100 hours, and the addition rate can be 0.001 to 100 mL / sec.
  • the zirconium salt Before mixing the aqueous solution containing the zirconium salt with the base, it is preferable to mix the zirconium salt with the water-soluble organic agent, and it is preferable to use a so-called surfactant as the water-soluble organic agent.
  • the surfactant include unsaturated fatty acids such as oleic acid, linoleic acid and ruuric acid and salts thereof (alkali metal salts such as sodium salt and potassium salt); and other carboxylic acids include saturated fatty acids and methyl tauric acid.
  • Sulfosuccinic acid and its salts alkali metal salts such as sodium salt and potassium salt); alkylbenzene sulfonic acid and its salts (alkali metal salts such as sodium salt and potassium salt); ⁇ -olefin sulfonic acid (tetradecene sulfonic acid and the like) and their salts.
  • Salts alkali metal salts such as sodium salt and potassium salt
  • alkyl sulfate ester acid, alkyl ether sulfate ester salt, phenyl ether sulfate ester salt, ether sulfate salt, alkyl sulfate salt, ether sulfonate and the like can be mentioned in the molecule.
  • Any organic agent having hydrophilic and hydrophobic functional groups can be widely used. Since these may be realized in a state of being adsorbed on the precipitated inorganic component, it is not necessary to form micelles, and there is no limitation on the concentration of the organic agent added such as the critical micelle concentration.
  • concentration of the organic agent added such as the critical micelle concentration.
  • a wide range of 0.001 to 1000 is applicable in which the ratio of the content of zirconium used in the production of monoclinic zirconia fine particle materials, aqueous solutions, colloidal solutions and nanosheet materials to the number of organic molecules added when expressed in atomic numbers is 0.001 to 1000. ..
  • the second step is characterized in that the aqueous solution containing the precipitate that has undergone the first step is placed under hydrothermal conditions, but the conditions of 180 ° C to 600 ° C, particularly 200 ° C to 500 ° C are preferable.
  • the holding time may be 12 hours or more, preferably 18 hours or more, and more preferably 24 hours or more.
  • the holding time is preferably held for a long time within an economically permissible range, and the upper limit is not particularly limited, but is usually preferably 1000 hours or less.
  • the container is preferably made of a material and shape that can withstand naturally generated pressure and temperature, but from the viewpoint of container durability, it is appropriate to use a corrosion-resistant material such as Teflon (registered trademark) for the inner container.
  • the solid content in the aqueous solution obtained in the second step can be separated and then dispersed in an organic solvent.
  • the method for separating the solid content in the aqueous solution obtained in the second step is not particularly limited, but the method of filtering after the centrifugation method, the operation of drying at about 100 ° C. from normal room temperature, or freezing and placing in vacuum conditions. It can be made into a solid by performing an operation, an operation of replacing it with another medium, or the like. At this time, if the nanoparticles are apparently solid in any aspect, the independent crystalline state of the individual nanoparticles is maintained.
  • the organic solvent is preferably a non-polar solvent, preferably toluene, benzene, petroleum ether, cyclohexane, heptane, dodecane, cyclohexene, mesitylene (1,3,5-trimethylbenzene), ethylbenzene, and jurene (1,2,4,5-tetra). Methylbenzene) and the like. Further, tetrachloromethane, chloroform, chlorobenzene, dichlorobenzene and the like can also be used.
  • the zirconia fine particles can be produced by removing the solvent of the solution after the second step (the aqueous solution obtained in the second step or the colloidal solution obtained in the third step). Further, when the solvent is removed after the third step, the independent crystalline state of the monoclinic zirconia fine particle material of the present invention is maintained, which is more preferable as a method for producing zirconia fine particles. Further, the solution after the second step (the aqueous solution obtained in the second step or the colloidal solution obtained in the third step) is added to the substrate or the substrate is immersed in the solution and taken out to obtain a zirconia nanosheet material. You can also do it.
  • Example 1 Reagent special grade zirconium nitrate (Fujifilm Wako Pure Chemical Industries, Ltd.) and potassium oleate (Fujifilm Wako Pure Chemical Industries, Ltd.) are weighed in predetermined amounts, dissolved in 30 mL of distilled water, and zirconium salt 7 mmol / L. An aqueous solution and a 7 mmol / L oleate aqueous solution were prepared. An aqueous solution of oleate was added to the aqueous solution of zirconium salt at room temperature with strong stirring, and 10 mL of 25% by mass aqueous ammonia was added to neutralize the mixture to form a precipitate.
  • Teflon (registered trademark) container containing this mixed solution was placed in a stainless steel pressurized container, and hydrothermal treatment was performed at 100 ° C. for 24 hours while stirring at 500 rpm. After that, the sample is naturally cooled to room temperature, the sample is collected, the solution after the reaction is centrifuged at 3000 rpm for 30 minutes, the contents are concentrated in the lower part of the sample tube, and the supernatant is washed with distilled water. The precipitate was dried in the air at 90 ° C. for 24 hours and then dispersed in toluene.
  • FIG. 1 shows a transmission electron microscope image of the particles produced in Example 1 in a solid state.
  • the particles do not independently connect to each other.
  • the number of connected particle groups was 2 or less.
  • the number of particles in the particles was within 2, and the particle size did not exceed 5 nanometers. That is, it can be understood that 95% or more of the particles exist in an independent state, and the abundance ratio of the single crystal is 95% or more.
  • a lattice image was seen by high-resolution observation, and the lattice image was observed without being divided over the entire particle, and it was found that the entire particle was one crystal.
  • FIG. 2 shows a distribution map of the particle size obtained from the field of view of FIG.
  • the average particle size was 2 nm, and 95% or more of the particles were 5 nm or less.
  • Example 2 In addition to setting the hydrothermal treatment temperature to 120 ° C. (Example 2), 140 ° C. (Example 3), and 160 ° C. (Example 4), samples of Examples 2 to 4 were prepared by the same operation as in Example 1.
  • FIG. 3 shows a transmission electron microscope image of the particles produced at 160 ° C. in Example 4 in a solid state.
  • the particles do not independently connect to each other.
  • the number of connected particle groups was 5 or less.
  • the number of particles was 2 or less, and the particle size did not exceed 10 nanometers. That is, it can be understood that 95% or more of the particles exist in an independent state, and the abundance ratio of the single crystal is 95% or more.
  • a lattice image was seen by high-resolution observation, and the lattice image was observed without being divided over the entire particle, and it was found that the entire particle was one crystal.
  • FIG. 4 shows a distribution map of the particle size obtained from the field of view of FIG.
  • the average particle size was 2 nm, and 95% or more of the particles were 5 nm or less.
  • FIG. 5 shows the powder X-ray diffraction pattern of the particles prepared at 100 ° C., 120 ° C., 140 ° C., and 160 ° C. in Examples 1 to 4 together with the sample (200 ° C.) of Comparative Example 1 described later. All of Examples 1 to 4 showed a diffraction pattern of tetragonal ZrO 2 under the conditions of 100 ° C. to 160 ° C., and no monoclinic crystal was observed in these samples. The X-ray diffraction pattern was the same even when the aqueous solution was measured in a dried sample after the hydrothermal treatment of Examples 1 to 4.
  • the crystallite diameter estimated by Scheller's formula which is often used for crystal measurement, is about 2 nm in each of Examples 1 to 4 depending on the composition, and very small crystals cannot be measured. Therefore, the numerical values are not always reliable, but fine crystals. Showed the existence of.
  • the average particle size of the toluene solution in Example 1 was measured with the Zetasizer Nano S manufactured by Malvern in the solution, and it was shown that the average particle size was 3 nm. That is, it can be understood that the nanocrystals described above are individually dispersed in the solution, and the zirconia single crystal is a colloidal solution dispersed in a particle size of 20 nm or less. The properties of this colloidal solution did not change after 2 months.
  • the surfactant is not potassium oleate but linoleic acid (Example 5), methyl tauric acid (Example 6) or sodium tetradecene sulfonate ( ⁇ -olefin sulfonic acid) (Example 7), and at 120 ° C.
  • a sample was prepared by the same operation as in Example 2. From the powder X-ray diffraction pattern of each of the prepared samples, a diffraction pattern of only tetragonal ZrO 2 was observed. In addition, even when the sample in the state where the aqueous solution was dried after the hydrothermal treatment by the X-ray diffraction pattern was measured again after heating at 600 ° C., only tetragonal ZrO 2 was found.
  • Example 8 In addition to setting the hydrothermal treatment temperature to 12 hours instead of 24 hours, Examples are performed at 100 ° C. (Example 8), 120 ° C. (Example 9), 140 ° C. (Example 10) or 160 ° C. (Example 11). Samples were prepared in the same manner as in steps 1 to 4. From the powder X-ray diffraction pattern, all the prepared samples showed a diffraction pattern of only tetragonal ZrO 2 , and no formation of monoclinic crystals was observed. It should be noted that even when the sample in which the aqueous solution was dried after hydrothermal treatment using an X-ray diffraction pattern was heated again at 600 ° C. and the sample was measured, only tetragonal ZrO 2 was found.
  • Comparative Example 1 In addition to setting the hydrothermal treatment temperature to 200 ° C., a sample of Comparative Example 1 was prepared by the same operation as in Example 1.
  • FIG. 5 shows a powder X-ray diffraction pattern of this sample together with Examples 1 to 4. Since the diffraction pattern of the monoclinic ZrO 2 was shown and the diffraction pattern of the tetragonal ZrO 2 was not seen, the zirconia produced under these conditions could not be obtained as a tetragonal crystal.
  • FIG. 6 shows a powder X-ray diffraction pattern of the zirconia fine particle materials of Examples 1 to 4 and Comparative Example 1 after being heated in the air at 600 ° C. for 3 hours.
  • Example 1 Catalyst test 1
  • the fine particles prepared by the same operation as in Example 2 (120 ° C.) and Comparative Example 1 (200 ° C.) were dried in the air at 100 ° C. overnight and then at 400 ° C. After heat-treating in 3 hours, each is impregnated with 0.4% by weight of rhodium using an aqueous solution of rhodium nitrate (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.), and heat-treated in the air at 600 ° C. for 3 hours to carry a rhodium-supporting catalyst.
  • a (from Example 2) and B (from Comparative Example 1) were prepared.
  • the exhaust model gas was circulated by a fixed bed flow catalyst test device to evaluate the catalyst purification performance.
  • the measurement operation is as follows: 0.1 g of sample is weighed into pellets, coarsely crushed and placed in a quartz test tube, a mixed gas having a gas composition simulating exhaust gas is flowed at 500 ml / min, and the temperature rise rate is 10 ° C./min. The temperature is raised to 600 ° C., held at 600 ° C. for 1 hour, then cooled, the temperature is raised again under the same conditions, the gas composition at the time of the temperature rise is measured, and carbon monoxide (CO) and hydrocarbons are measured.
  • CO carbon monoxide
  • the purification characteristics (light-off characteristics) of (HC) and nitrogen oxides (NO) were evaluated.
  • the mixed gas composition (volume%) used was C 3 H 6 0.04%, NO 0.1%, CO 0.3%, O 2 0.33%, H 2 0.1%, H 2 O 2%, and the others were N 2 .
  • Test Example 2 Catalyst test 2
  • the final heat treatment temperature at the time of producing the catalyst was set to 800 ° C. instead of 600 ° C., and rhodium-supported catalysts C (from Example 2) and D (from Comparative Example 1) were produced by the same operation as in Test Example 1. , An evaluation test was conducted.
  • Table 1 summarizes the temperatures at which the purification rates of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NO) are 80%.
  • Reagent special grade zirconium nitrate (Fujifilm Wako Pure Chemical Industries, Ltd.) and potassium oleate (Fujifilm Wako Pure Chemical Industries, Ltd.) are weighed in predetermined amounts, dissolved in 30 mL of distilled water, and zirconium salt 7 mmol / L.
  • An aqueous solution and a 7 mmol / L oleate aqueous solution were prepared.
  • An aqueous solution of oleate was added to the aqueous solution of zirconium salt at room temperature with strong stirring, and 10 mL of 25% by mass aqueous ammonia was added to neutralize the mixture to form a precipitate.
  • Teflon (registered trademark) container containing this mixed solution is placed in a stainless steel pressurized container, and the mixture is stirred at 500 rpm for 12 hours (Example 12) or 48 hours (Example 13) at 200 ° C. Hydrothermal treatment was performed. After that, the sample is naturally cooled to room temperature, the sample is collected, the solution after the reaction is centrifuged at 3000 rpm for 30 minutes, the contents are concentrated in the lower part of the sample tube, and the supernatant is washed with distilled water. The precipitate was dried in the air at 90 ° C. for 24 hours and then dispersed in toluene.
  • FIG. 7 shows a powder X-ray diffraction pattern of particles prepared at 200 ° C. in Examples 12 (12 hours) and 13 (48 hours). Both showed a diffraction pattern of monoclinic ZrO 2 .
  • the X-ray diffraction pattern was the same even when the aqueous solution was measured with a sample in a dried state after the hydrothermal treatment.
  • FIG. 8 shows a transmission electron microscope image of the particles produced in Example 13 (48 hours) in a solid state.
  • all particles were materials that did not show a general shape and were characterized by branching.
  • the number of particles having a shape in which a plurality of protrusions extend in irregular directions accounts for 85% of the total, and the number of particles having three or more branches is 60 in the total. Occupied%.
  • Some particles had a particle size of 5 nanometers or less.
  • a lattice image was seen by high-resolution observation, and the lattice image was observed without being divided over the entire particle, and the entire particle was one crystal, or it was a different crystal for each branched region. ..
  • Example 12 When the sample of Example 12 (12 hours) was also measured in the same manner, all the particles did not show a general shape and were characterized by having branches, and a plurality of protrusions in irregular directions. The number of particles having an elongated shape accounted for 75% of the total, and the number of particles having three or more branches accounted for 55% of the total.
  • the average particle size of the particles obtained from FIG. 8 was calculated to be 13.2 nm.
  • the mean particle diameter means the area length mean diameter calculated from the circle equivalent diameter of each particle using imageJ in the electron microscope image.
  • FIG. 9 shows a distribution map of the particle size obtained from the field of view of FIG.
  • it was a zirconia fine particle material in which the proportion of particles having a particle size of 5 to 30 nm was 80% or more.
  • the average particle size of the toluene solution was measured with Zetasizer Nano S manufactured by Malvern, it was shown to be about 12 nm. That is, the nanocrystals described above are individually dispersed and present in the solution, forming a dispersed colloidal solution. The characteristics of this solution did not change even after 2 months.
  • Example 12 When the sample of Example 12 (12 hours) was also measured in the same manner, the proportion of particles having a particle size of 5 to 30 nm was 75% in the solid state, and the average particles of the toluene solution were averaged with Zetasizer Nano S manufactured by Malvern. The diameter was measured and found to be about 10 nm.
  • the average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
  • Example 14 Zirconia nanoparticles were supported on a Si single crystal plate using the toluene dispersion prepared in Example 13 (prepared under hydrothermal conditions at 200 ° C. for 48 hours). After drying in the air at 100 ° C. overnight, the surface morphology in the solid state was observed with an SPM9700 atomic force microscope manufactured by Shimadzu Corporation. At the same time, the thickness from the substrate to the particle surface was measured by the same machine.
  • FIG. 10 shows an observation image of the 14th embodiment. In this observation, each particle having an average thickness of 1 ⁇ 0.3 nm was observed, and was partially connected to form a film on the substrate.
  • the particles existed along the substrate, and the thickness of the particles was measured and found to be 3 nm or less in this field of view. Further, in the film form shown between AB, a nanosheet material having a thickness of 2 ⁇ 0.3 nm and covering the substrate over a distance of 300 nm was formed. That is, these particles are a sheet-like material characterized by a sheet-like shape and having a thickness of all particles of 3 nm or less. Further, the formation of the zirconia nanosheet material was realized by adding the solution onto the substrate or immersing the substrate in the solution and taking it out. When the sample of Example 12 (12 hours) was also measured in the same manner, particles having an average thickness of 1 ⁇ 0.3 nm were observed, and a nanosheet material having a thickness of 2 ⁇ 0.3 nm was formed. It was.
  • the surfactant is not potassium oleate but linoleic acid (Example 15), methyl tauric acid (Example 16) or sodium tetradecene sulfonate ( ⁇ -olefin sulfonic acid) (Example 17), and at 200 ° C.
  • a sample was prepared in 48 hours under the same preparation conditions as in Examples 12 to 14. From the powder X-ray diffraction pattern of each of the prepared samples, a diffraction pattern of monoclinic ZrO 2 was observed.
  • Example 15 all the particles are materials that do not show a general shape and are characterized by having branches, and the total number of particles having a shape in which a plurality of protrusions extend in irregular directions is 80 in total.
  • the number of particles with 3 or more branches accounts for 50% of the total, the proportion of particles with a particle size of 5 to 30 nm is 80%, and the Zetasizer Nano S manufactured by Malvern is used for the toluene solution.
  • the average particle size was about 12 nm.
  • particles having an average thickness of 1 ⁇ 0.3 nm were observed, and nanosheet materials having a thickness of 2 ⁇ 0.3 nm were also formed.
  • the average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
  • Example 16 all the particles are materials that do not show a general shape and are characterized by having branches, and the total number of particles having a shape in which a plurality of protrusions extend in irregular directions is 75 in total.
  • the number of particles with 3 or more branches accounts for 45% of the total, the proportion of particles with a particle size of 5 to 30 nm is 80%, and the Zetasizer Nano S manufactured by Malvern is used for the toluene solution.
  • the average particle size was about 14 nm.
  • particles having an average thickness of 1 ⁇ 0.3 nm were observed, and nanosheet materials having a thickness of 2 ⁇ 0.3 nm were also formed.
  • the average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
  • Example 17 all the particles do not show a general shape and are characterized by having branches, and the total number of particles having a shape in which a plurality of protrusions extend in irregular directions is 70 in total.
  • the number of particles with 3 or more branches accounts for 45% of the total, the proportion of particles with a particle size of 5 to 30 nm is 80%, and the Zetasizer Nano S manufactured by Malvern is used for the toluene solution.
  • the average particle size was about 14 nm.
  • particles having an average thickness of 1 ⁇ 0.3 nm were observed, and nanosheet materials having a thickness of 2 ⁇ 0.3 nm were also formed.
  • the average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
  • Example 18 The hydrothermal treatment temperature was set to 200 ° C. for 72 hours, and a sample was prepared by the same operation as in Examples 12 to 14. From the powder X-ray diffraction pattern of the prepared sample, a monoclinic ZrO 2 and a branched particle material were formed. All particles do not show a general shape and are characterized by having branches, and the number of particles having a shape in which multiple protrusions extend in irregular directions accounts for 70% of the total. The number of particles having three or more branches accounts for 60% of the total, and the proportion of particles having a particle size of 5 to 30 nm is 80%. The particle size of the toluene solution is determined by Malvern Zetasizer Nano S.
  • the average particle size was about 16 nm.
  • particles having an average thickness of 1 ⁇ 0.3 nm were observed, and nanosheet materials having a thickness of 2 ⁇ 0.3 nm were also formed.
  • the average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
  • Tetragonal zirconia was prepared by adding aqueous ammonia to the solution, heating and drying the mixture, crushing the solid, and calcining the mixture in the air at 500 ° C. for 1 hour to prepare a comparative material (Comparative Example 2). These samples were calcined in the air at 600 ° C. for 3 hours to obtain powders of monoclinic crystals (Example 13) and tetragonal crystals (Comparative Example 2).
  • the dispersity of the catalyst from Comparative Example 2 was 0.2, and that of the sample from Example 13 was 0.55.
  • the material of Example 13 was excellent in improving the dispersibility of the Rh catalyst. This is considered to be due to the monoclinic zirconia particles having a peculiar shape.
  • the dispersion performance of metal components is known to be effective in improving the activity of catalysts, and is the effect of interactions that depend on the surface structure that comes from the crystal structure and shape. Therefore, the same material can be used with other precious metals and active metals. The effect of can be expected.
  • Example 4 In order to evaluate the characteristics of the monoclinic zirconia fine particle material of the present invention as a catalyst carrier, the fine particle solution of Example 12 was washed and dried, and then calcined in the air at 600 ° C. for 3 hours to obtain a powder.
  • the tetragonal zirconia fine particle material of the present invention and the method for producing the same have fewer steps than the conventional method, are easy to operate, and the material can be easily obtained.
  • a carrier or an additive for a metal-supported catalyst having good exhaust gas purification characteristics even at a low temperature tetragonal nanoparticles can be utilized and used as an environmental purification material.
  • the colloidal solution itself is stable even when stored for a long period of time, and can be used as a raw material when nanoparticles are used as a filler. Nanoparticles can be applied as various components as additives that utilize the chemical, optical, and physical properties of various materials including zirconia.
  • the monoclinic zirconia fine particle material of the present invention is a material in which the proportion of tetragonal crystals containing 100% of the total crystal phase is 20% or less and the average particle size is 5 to 30 nm, and the colloidal solution itself is long. It is stable even if it is stored for a period of time.
  • nanoparticles When nanoparticles are used as fillers and adsorbents, they can be used as raw materials, and are materials that utilize the chemical, optical, electromagnetic, physical, and mechanical properties of various materials including zirconia. Nanoparticle materials can be applied together with various components. Furthermore, nanoparticles and film properties can be utilized as carriers and additives for the metal-supporting catalyst, and can be used as environmental purification materials and functional materials.
  • the manufacturing method is simple and has versatility that can be widely applied.

Abstract

(1) A tetragonal zirconia microparticulate material in which the ratio of the content of monoclinic crystals is 10% or less wherein the total amount of all of crystal phases is defined as 100%, the average grain diameter is 20 nm or less, and the ratio of the content of single crystals is 90% or more wherein the total amount of all of crystals is defined as 100%. By using the tetragonal zirconia microparticulate material, it is possible to provide: tetragonal unstabilized zirconia nanoparticles each having the form of a single crystal; a simple method for producing the tetragonal unstabilized zirconia nanoparticles; and a use of the tetragonal unstabilized zirconia nanoparticles as a catalyst material. (2) A monoclinic zirconia microparticulate material in which the ratio of the content of tetragonal crystals is 20% or less and the ratio of the content of grains each having a grain diameter of 5 to 30 nm is 60% or more wherein the total amount of all of crystal phases is defined as 100%. By using the monoclinic zirconia microparticulate material, it is possible to provide: zirconia microparticles each of which can be used as a single nanoparticulate crystal and has a complicated form or a nanosheet-like form; a simple method for producing the zirconia microparticles; and a use of the zirconia microparticles as a catalyst material.

Description

ジルコニア微粒子材料、ガス処理用触媒及びその製造方法Zirconia fine particle material, catalyst for gas treatment and its manufacturing method
　本発明は、触媒担体等に利用されるジルコニア微粒子材料及びその製造方法に関する。 The present invention relates to a zirconia fine particle material used as a catalyst carrier and the like and a method for producing the same.
　従来、ジルコニウム酸化物（以下、「ジルコニア」と言うこともある）及びその粉末は、高強度材料、電子素子、燃料電池材料、機能性セラミックス、触媒材料等の分野で使用されている。最近は、自動車排ガス浄化触媒等のガス処理用触媒の担体としての利用が重要となっており、微粒化された純粋なジルコニア材料等が必要となっている。 Conventionally, zirconium oxide (hereinafter, also referred to as "zirconia") and its powder have been used in the fields of high-strength materials, electronic devices, fuel cell materials, functional ceramics, catalyst materials, and the like. Recently, it has become important to use it as a carrier for a catalyst for gas treatment such as an automobile exhaust gas purification catalyst, and an atomized pure zirconia material or the like is required.
　ジルコニアの製造方法としては、純度、粒径の微細化及び均一化、さらには量産性の点から、主として沈殿法が広く用いられている。また、ジルコニアはそのままでは相転移を起こすことから希土類元素を添加した状態で利用されていることが多い。さらには、特に近年の極微粒化の要請もあり、ジルコニア微粒子として安定化されて且つナノ粒子状態であることは困難であることから開発が行われており、以下に述べるような種々の手法が提案されている。 As a method for producing zirconia, the precipitation method is widely used mainly from the viewpoints of purity, particle size miniaturization and homogenization, and mass productivity. In addition, since zirconia causes a phase transition as it is, it is often used in a state where a rare earth element is added. Furthermore, especially in recent years, there has been a demand for ultrafine particles, and it is difficult to stabilize the zirconia fine particles and to be in the nanoparticle state. Therefore, various methods as described below have been developed. Proposed.
　特許文献１には、ジルコニウム塩とイットリウム塩等とを加水分解した後にろ過膜を通過させて高純度のジルコニア系コロイドゾルを製造する方法が開示されている。 Patent Document 1 discloses a method for producing a high-purity zirconia-based colloid sol by hydrolyzing a zirconium salt, an yttrium salt, or the like and then passing the zirconium salt through a filtration membrane.
　特許文献２には、ジルコニウム塩とカルシウム塩等の塩基とを加熱熟成することにより、正方晶または立方晶のジルコニアゾルの製造方法が開示されている。 Patent Document 2 discloses a method for producing a tetragonal or cubic zirconia sol by heat-aging a zirconium salt and a base such as a calcium salt.
　特許文献３には、アルカリ土類金属酸化物をジルコニアに固溶してなるナノ粒子を、原料塩混合物水溶液のｐＨを７以上として沈殿物を生成させ、４００℃以上に加熱し、前記アルカリ土類金属酸化物ドープジルコニア正方晶ナノ粒子を製造する方法が開示されている。 In Patent Document 3, nanoparticles formed by solid-dissolving an alkaline earth metal oxide in zirconia are heated to 400 ° C. or higher by setting the pH of the raw material salt mixture aqueous solution to 7 or higher to form a precipitate, and the alkaline soil is described. A method for producing metal oxide-doped zirconia square nanoparticles is disclosed.
　特許文献４には、Sc、Y及びYbのいずれかを添加し、平均粒子径が１０ｎｍ以下の安定化ジルコニア微粒子であって、安定化ジルコニアの結晶相が正方晶である微粒子を、亜臨界ないし超臨界状態の水を媒体として生成する製造方法が開示されている。 In Patent Document 4, any of Sc, Y, and Yb is added, and fine particles having an average particle diameter of 10 nm or less and having a tetragonal crystal phase of stabilized zirconia are subcritical or subcritical. A production method for producing water in a supercritical state as a medium is disclosed.
　これらの方法及びジルコニア微粒子では、正方晶とするために他の元素添加が共通に利用されており、他の元素を添加しない単結晶状のジルコニアナノ粒子（以下、「無添加ジルコニアナノ粒子」と言うこともある）は得られていない。ところで、無添加ジルコニアナノ粒子は、900℃以下で単斜晶が安定であり、このような無添加ジルコニアナノ粒子を得る方法としては、以下に示すようないくつかの手法が開発されている。 In these methods and zirconia fine particles, addition of other elements is commonly used to form tetragonal crystals, and single crystal zirconia nanoparticles without addition of other elements (hereinafter referred to as "additive-free zirconia nanoparticles"). (Sometimes I say) has not been obtained. By the way, monoclinic crystals of additive-free zirconia nanoparticles are stable at 900 ° C. or lower, and several methods as shown below have been developed as methods for obtaining such additive-free zirconia nanoparticles.
　特許文献５には、溶媒の中に一次粒子の平均粒径が１ｎｍ～３０ｎｍの無機微粒子が凝集した状態で存在し、金属アルコキシドを含む混合溶液を、分散装置の分散容器に供給し、前記分散容器で１５μｍ～３０μｍのビーズを用いて攪拌すると同時に超音波を前記分散容器に印加して、前記無機微粒子を分散処理することを特徴とする無機微粒子分散溶液の製造方法が開示されている。 In Patent Document 5, inorganic fine particles having an average particle size of 1 nm to 30 nm of primary particles are present in a solvent in an agglomerated state, and a mixed solution containing a metal alkoxide is supplied to a dispersion container of a dispersion device to disperse the particles. A method for producing an inorganic fine particle dispersion solution is disclosed, which comprises stirring the particles in a container using beads having a size of 15 μm to 30 μm and simultaneously applying ultrasonic waves to the dispersion container to disperse the inorganic fine particles.
　特許文献６には、表面修飾した単斜晶ジルコニア粒子が開示され、２５０～４００℃での水熱条件により製造できる技術が開発されている。実施例によれば正方晶ジルコニアになる場合には粒子径が著しく増加してナノ粒子状態を保持せず利用に適さないとされている。 Patent Document 6 discloses surface-modified monoclinic zirconia particles, and has developed a technique capable of producing them under hydrothermal conditions at 250 to 400 ° C. According to the examples, when tetragonal zirconia is formed, the particle size is remarkably increased and the nanoparticle state is not maintained, which is not suitable for use.
　特許文献７には、金属塩水和物と酸と溶媒とを含む原料液を、加圧下、前記溶媒が分解して生成するヒドロキシル基を含む化合物の臨界温度以下で加熱する工程を含むジルコニアナノ粒子の製造方法が開示されており、その結晶相はXRD図形から単斜晶であった。 Patent Document 7 includes zirconia nanoparticles comprising a step of heating a raw material solution containing a metal salt hydrate, an acid, and a solvent at a temperature below the critical temperature of a compound containing a hydroxyl group produced by decomposition of the solvent under pressure. The manufacturing method of the above was disclosed, and the crystal phase was monoclinic from the XRD diagram.
　これらの技術によれば、ナノ粒子の状態で単斜晶ジルコニアは比較的得られやすいが、正方晶ジルコニアは得られにくいことがわかる。正方晶ジルコニアについては以下のような技術が開発されている。 According to these techniques, it can be seen that monoclinic zirconia is relatively easy to obtain in the nanoparticle state, but tetragonal zirconia is difficult to obtain. The following technologies have been developed for tetragonal zirconia.
　特許文献８には、ジルコニア粒子と分散媒とを含有してなるジルコニア透明分散液であって、ジルコニア粒子は分散粒径が１ｎｍ～２０ｎｍの正方晶ジルコニア粒子であることを特徴とするジルコニア透明分散液、及び該正方晶ジルコニア粒子を樹脂中に分散してなることを特徴とする透明複合体を開示している。透明分散液の製造方法については実施例でしか開示がなく、オキシ塩化ジルコニウム塩溶液にアンモニア水を攪拌しながら加えスラリーを調整し、硫酸ナトリウム水溶液を攪拌しながら加えたのち、混合物を、乾燥器を用いて、大気中１３０℃で乾燥させ、固形物を得て、次いで、この固形物を自動乳鉢等により粉砕した後、電気炉を用いて大気中５００℃にて１時間焼成し、この焼成物を純水中に投入し攪拌してスラリー状とした後、遠心分離器を用いて洗浄を行い、添加した硫酸ナトリウムを十分に除去した後、乾燥させ、ジルコニア粒子を作製し、次いで、このジルコニア粒子に、トルエン、市販の分散剤を加え分散処理を行い、ジルコニア透明分散液を作製している。 Patent Document 8 describes a zirconia transparent dispersion liquid containing zirconia particles and a dispersion medium, wherein the zirconia particles are tetragonal zirconia particles having a dispersion particle size of 1 nm to 20 nm. Disclosed is a transparent composite characterized in that the liquid and the tetragonal zirconia particles are dispersed in a resin. The method for producing the transparent dispersion is disclosed only in Examples, and the slurry is prepared by adding aqueous ammonia to the solution of zirconium oxychloride with stirring, and the aqueous solution of sodium sulfate is added with stirring, and then the mixture is added to a dryer. To obtain a solid substance by drying in the air at 130 ° C., then the solid substance is crushed by an automatic dairy pot or the like, and then calcined in the air at 500 ° C. for 1 hour using an electric furnace. The product was put into pure water and stirred to form a slurry, which was then washed using a centrifuge to sufficiently remove the added sodium sulfate, and then dried to prepare zirconia particles. To the zirconia particles, toluene and a commercially available dispersant are added and subjected to a dispersion treatment to prepare a zirconia transparent dispersion solution.
　特許文献９には、２種以上の被覆剤により被覆された正方晶の酸化ジルコニウムを含む酸化ジルコニウムナノ粒子とその酸化ジルコニウムナノ粒子を含有する塗料組成物等を開示している。例えば、酸化ジルコニウムの製造法では、少なくとも酸化ジルコニウム前駆体と特定の被覆剤から被覆剤－ジルコニウム複合体をあらかじめ調製することで、１ＭＰａＧ未満という比較的温和な条件の水熱反応で酸化ジルコニウムナノ粒子を合成できることが開示されている。 Patent Document 9 discloses a zirconium oxide nanoparticles containing tetragonal zirconium oxide coated with two or more kinds of coating agents, and a coating composition containing the zirconium oxide nanoparticles. For example, in the method for producing zirconium oxide, by preparing a coating agent-zirconium composite in advance from at least a zirconium oxide precursor and a specific coating agent, zirconium oxide nanoparticles are subjected to a hydrothermal reaction under relatively mild conditions of less than 1 MPaG. It is disclosed that can be synthesized.
特公平３－５５４１３号公報Special Fair 3-55413 Gazette 特公平４－７２７６８号公報Special Fair 4-72768 Gazette 特許第５７６０３０１号Patent No. 5760301 特許第５４６７２５５号Patent No. 5467255 特許第５６７９６４０号Patent No. 5679640 特許第５４４５１４０号Patent No. 5445140 特開２０１７－１６５６１６号公報Japanese Unexamined Patent Publication No. 2017-165616 特許第５０１１６９５号Patent No. 501169 特許第５０３０６９４号Patent No. 5030694
　上記の特許文献からジルコニアに要求される特性である微結晶の状態、均一性等を保持する材料やその製造方法を目指した幾多の技術が記載されている。しかし、開発の成果が開示されているにもかかわらず、微粒子が、他の金属元素酸化物を固溶せずに、正方晶ジルコニア単結晶であり、さらにはそれ自体が独立した粒子の形態を確実に示しているナノ材料とコロイド液の作製については依然困難がある。すなわち、他の元素が無添加で、ジルコニア単独で結晶系が正方晶である単結晶状のジルコニアナノ粒子を得る方法は以下のように難点があるためその利用は促進されていない。 From the above patent documents, a number of technologies aimed at materials that maintain the state and uniformity of microcrystals, which are the characteristics required for zirconia, and their manufacturing methods are described. However, despite the disclosure of the results of the development, the fine particles are tetragonal zirconia single crystals without solid solution of other metal element oxides, and even in the form of independent particles themselves. There are still difficulties in producing the nanomaterials and colloidal solutions that are shown for sure. That is, the method of obtaining single crystal zirconia nanoparticles having a tetragonal crystal system with zirconia alone without adding other elements has the following drawbacks, and its use has not been promoted.
　正方晶の無添加ジルコニアが得られること自体は知られており、ジルコニアは低温で単斜晶、温度の上昇とともに正方晶又は立方晶に相変態する。そのため、正方晶は、１２００℃付近では安定である。一方、正方晶は準安定相として沈殿法等による微粒子の凝集体としてその凝集が強い場合に拘束され生成するとされ、加熱等による粒子の粗大化とともに安定な単斜晶に変態することが報告されている。また、ゾルゲル法等の微粒子合成時の固化体内にナノ粒子が拘束されたり、結晶化時に強く凝集した多結晶粒子として、さらにはそれらの低温で焼成した塊状物に存在する。すなわち、単独のナノ粒子の結晶として正方晶ジルコニアは生成しがたいと考えらえる。 It is known that tetragonal additive-free zirconia can be obtained, and zirconia undergoes phase transformation into monoclinic crystals at low temperatures and into tetragonal or cubic crystals as the temperature rises. Therefore, the tetragonal crystal is stable at around 1200 ° C. On the other hand, it is reported that tetragonal crystals are generated as metastable phases as aggregates of fine particles by the precipitation method, etc., when the aggregation is strong, and they are transformed into stable monoclinic crystals as the particles become coarser due to heating or the like. ing. Further, nanoparticles are constrained in the solidified body at the time of fine particle synthesis such as the sol-gel method, or exist as polycrystalline particles strongly aggregated at the time of crystallization, and further in the agglomerates fired at a low temperature. That is, it can be considered that tetragonal zirconia is difficult to be produced as a single nanoparticle crystal.
　例えば、特許文献８では、この生成の困難に対するため複雑で多段階の処理工程を必要とする製造法を開示している。その中に、添加剤除去のためにやむをえず５００℃の焼成工程があるが、これによって焼結現象が起こり、すべてのジルコニアがナノ粒子状態で得られにくいことが考えられる。実施例では７ｎｍの分散粒径が得られたとされているが、記載と同様にして作製したナノ粒子の焼成後粉末を市販分散剤とともに溶媒に混合する処理によっては、一部の粒子しか溶媒内に分散せずに多くが凝集したままとなりジルコニアナノ粒子を得る収率は低い。さらには、それらの粒子が単結晶状であるかについては、焼成時の凝集のため単結晶を維持することが困難であることが容易に推定される。 For example, Patent Document 8 discloses a manufacturing method that requires a complicated and multi-step processing process in order to deal with this difficulty in production. Among them, there is an unavoidable firing step at 500 ° C. for removing additives, which causes a sintering phenomenon, and it is considered that it is difficult to obtain all zirconia in the nanoparticle state. In the examples, it is said that a dispersed particle size of 7 nm was obtained, but depending on the treatment of mixing the calcined powder of the nanoparticles produced in the same manner as described in the solvent together with a commercially available dispersant, only some of the particles are contained in the solvent. The yield of obtaining zirconia nanoparticles is low because many of them remain agglomerated without being dispersed in the solvent. Furthermore, it is easily presumed that it is difficult to maintain a single crystal due to aggregation during firing as to whether the particles are single crystal.
　特許文献９には、水熱法を用いた方法が開示されている。しかしながらその処理温度は１８０℃以下とされているものの、実施例では１８０℃まで加熱されているように、高温加熱を必要としている。また、ジルコニア粒子の沈殿物除去のため、濾過で粗大粒子を除去する工程を有しているため、このような微粒子の選別に多大な時間と設備を要する。 Patent Document 9 discloses a method using a hydrothermal method. However, although the treatment temperature is 180 ° C. or lower, high-temperature heating is required as in the examples where the temperature is 180 ° C. or lower. In addition, since it has a step of removing coarse particles by filtration for removing the precipitate of zirconia particles, it takes a lot of time and equipment to select such fine particles.
　すなわち、正方晶ジルコニアナノ粒子は、単斜晶ジルコニアナノ粒子よりもナノ粒子の生成が困難であるため、その製造には多段、複雑な工程を要しており、広い応用に向けた素材となっていない問題があった。 That is, since tetragonal zirconia nanoparticles are more difficult to generate nanoparticles than monoclinic zirconia nanoparticles, their production requires multiple steps and complicated steps, and is a material for a wide range of applications. There was a problem that was not.
　一方、背景技術で示したようなナノレベルの大きさの微粒子については、非常に小さいため、その形態に関する知見が不明である。最近の研究では、特異形態がもたらす効果が注目されており、ロッドやナノシート等の形態、花弁状等の複雑な形状等の生成に関心が払われている。しかしながら、上記のような開発においては、複雑で特異な形状は開発されておらず、微粒子の触媒や吸着剤、また担体としての利用には限界があった。 On the other hand, the nano-level size fine particles as shown in the background technology are very small, so the knowledge about their morphology is unknown. In recent studies, attention has been paid to the effects of peculiar morphology, and attention has been paid to the generation of morphology such as rods and nanosheets, and complex shapes such as petals. However, in the above-mentioned development, a complicated and peculiar shape has not been developed, and there is a limit to the use of fine particles as a catalyst, an adsorbent, and a carrier.
　微粒子がもつ形態の制御する技術には依然困難がある。すなわち、ジルコニア単独で複雑形状、シート状等である形態、状態のジルコニアナノ粒子及びその製造法は、これまで知られていないため、ジルコニアの有効性の範囲が限られ、ナノ粒子の利用は促進されていない。 There are still difficulties in the technology for controlling the morphology of fine particles. That is, since zirconia nanoparticles having a complicated shape, a sheet shape, or the like and a method for producing the same have not been known so far, the range of effectiveness of zirconia is limited and the use of nanoparticles is promoted. It has not been.
　単斜晶の無添加ジルコニアが得られること自体は知られており、ジルコニアは低温で単斜晶、温度の上昇とともに正方晶又は立方晶に相変態する。沈殿法等による微粒子の凝集体としてその凝集が強い場合に加熱等による粒子の粗大化とともに塊状の粒子に変化する。薄膜の形成に適するとされるゾルゲル法等合成時でも、前駆体の結晶化をともなう熱変化が必要なため、３ｎｍ以下の厚みのナノ粒子を形成、維持することは困難であり、多くは結晶化時に強く凝集した多結晶粒子として塊状物となる。すなわち、単独のナノ粒子の結晶として複雑形状あるいはナノシート状のジルコニアは生成しがたく、いまだにそのような例を見ない。 It is known that monoclinic additive-free zirconia can be obtained, and zirconia undergoes phase transformation into monoclinic crystals at low temperatures and into tetragonal or cubic crystals as the temperature rises. When the agglomeration of fine particles is strong as agglomerates of fine particles by a precipitation method or the like, the particles change to agglomerate particles as the particles become coarse due to heating or the like. Even during synthesis such as the sol-gel method, which is considered to be suitable for forming thin films, it is difficult to form and maintain nanoparticles with a thickness of 3 nm or less because thermal changes are required with crystallization of the precursor, and most of them are crystals. It becomes a mass as polycrystalline particles that are strongly aggregated during crystallization. That is, it is difficult to form zirconia having a complicated shape or a nanosheet shape as a crystal of a single nanoparticle, and such an example has not been seen yet.
　純粋な正方晶ジルコニア単結晶微粒子やその分散液は、ガス処理に有効な触媒担体やセラミックス前駆体として有用であるにもかかわらず、ナノレベルの単結晶状粒子として得られにくいため、これらの応用に関する正方晶ジルコニアの利用を妨げられていた。単分散で単結晶のナノサイズの正方晶ジルコニア粒子は、デバイス用に配列可能な原料として、また、ネックでのロスがなくすべてが表面として露出している吸着材や触媒材料として、さらに成形体の充填剤としてなど、広い範囲で応用可能な素材として期待される。一方、純粋なジルコニア微粒子及びその分散液は、ガス処理に有効な触媒担体やセラミックス前駆体として有用であるにもかかわらず、ナノレベルの粒子として得られにくい。さらには、１つの粒子が複雑形状を有する場合には、活性部位が特異的に現れ、さらにはナノシート形状となるとそれ自体が異方性による特異性をもつことが予想される。さらには、基板上にナノシートを設置すれば極薄膜材の利用が広がる。このような特異な形状を有するジルコニア粒子を製造することができれば、デバイス用に配列可能な原料として応用可能な素材として期待される。 Although pure tetragonal zirconia single crystal fine particles and their dispersions are useful as catalyst carriers and ceramic precursors effective for gas treatment, they are difficult to obtain as nano-level single crystal particles, so these applications The use of tetragonal zirconia was hindered. Monodisperse, single crystal nano-sized tetragonal zirconia particles can be used as raw materials that can be arranged for devices, as adsorbents and catalyst materials that are all exposed as a surface without loss at the neck, and as a molded product. It is expected to be a material that can be applied in a wide range, such as as a filler for. On the other hand, pure zirconia fine particles and a dispersion thereof are difficult to obtain as nano-level particles, although they are useful as catalyst carriers and ceramic precursors effective for gas treatment. Furthermore, when one particle has a complex shape, the active site appears specifically, and when it becomes a nanosheet shape, it is expected that the particle itself has anisotropy specificity. Furthermore, if nanosheets are placed on the substrate, the use of ultra-thin film materials will expand. If zirconia particles having such a peculiar shape can be produced, it is expected as a material that can be applied as a raw material that can be arranged for a device.
　また、一般の従来の技術では強く凝集した状態として得られたので、その表面の性質を十全には利用できない材料となっていた。特に高活性をもたらそうとする触媒材料の開発ではその効果が粒子表面すべてにわたっては元来期待できなかった。また、その改善のための技術にあっても、上記のようにナノ粒子状態を得るのに複雑で多段の工程を有し、さ　らにはそのナノ粒子が単結晶状である状態と確定する技術はこれまで知られていない。また、特異表面として露出している吸着材や触媒材料として、さらに成形体の充填剤として等、広い範囲があるにもかかわらず、その状態を確定する技術はこれまで知られていない。 In addition, since it was obtained as a strongly aggregated state by general conventional technology, it was a material that could not fully utilize the surface properties. Especially in the development of catalyst materials that are intended to bring about high activity, the effect could not be expected from the beginning over the entire particle surface. In addition, even with the technology for improving it, it has a complicated and multi-step process to obtain the nanoparticle state as described above, and further, it is determined that the nanoparticle is in a single crystal state. The technology has never been known. Further, although there is a wide range such as an adsorbent or a catalyst material exposed as a peculiar surface and a filler for a molded product, a technique for determining the state has not been known so far.
　本発明は、このような単結晶状の正方晶の無添加ジルコニアナノ粒子、およびその簡便な製造方法、その触媒材としての利用法を提供することを課題とする。本発明は、さらに、単独のナノ粒子の結晶として複雑形状あるいはナノシート状のジルコニア微粒子、及びその簡便な製造方法、その触媒材としての利用法を提供することも課題とする。 An object of the present invention is to provide such single crystal tetragonal additive-free zirconia nanoparticles, a simple method for producing the same, and a method for using the same as a catalyst material. Another object of the present invention is to provide zirconia fine particles having a complicated shape or nanosheets as crystals of single nanoparticles, a simple method for producing the same, and a method for using the zirconia as a catalyst material.
　本発明者は、鋭意努力した結果、含有する単斜晶ジルコニア結晶相の割合が１０％以下であり、平均粒子径が２０ｎｍ以下であり、単結晶の割合が９０％以上であるジルコニア微粒子材料を得ることに成功した。このジルコニア微粒子材料は、例えば、ジルコニウム塩を含む水溶液を中和して沈殿物を得てさらに温和な条件で水熱反応を行う簡略な処理をほどこすことにより、正方晶ジルコニアが単結晶状ナノ粒子として得られ、さらには性能に優れた高い触媒用担体としても利用できる技術を開発し、上記課題が解決しうることを見出した。一方、本発明者は、全結晶相を１００％として含有する正方晶の割合が２０％以下であり、粒径が５～３０ｎｍの粒子の割合が６０％以上である、単斜晶ジルコニア微粒子材料を得ることに成功した。このジルコニア微粒子材料は、例えば、ジルコニウム塩を含む水溶液を中和して沈殿物を得てさらに温和な条件で水熱反応を行う簡略な処理をほどこすことにより、単斜晶ジルコニアが特異形状のナノ粒子として得られ、さらには性能に優れた高い触媒用担体としても利用できる技術を開発し、上記課題が解決しうることを見出した。すなわち、本発明によれば、以下のジルコニア微粒子材料、ガス処理用触媒、水溶液若しくはコロイド溶液及びこれらの製造方法を包含する。 As a result of diligent efforts, the present inventor has produced a zirconia fine particle material having a monoclinic zirconia crystal phase content of 10% or less, an average particle size of 20 nm or less, and a single crystal ratio of 90% or more. I succeeded in getting it. In this zirconia fine particle material, for example, a simple treatment of neutralizing an aqueous solution containing a zirconium salt to obtain a precipitate and conducting a hydrothermal reaction under mild conditions is performed to obtain a single crystal nano of square zirconia. We have developed a technology that can be obtained as particles and can also be used as a carrier for catalysts with excellent performance, and found that the above problems can be solved. On the other hand, the present inventor is a monoclinic zirconia fine particle material in which the proportion of tetragonal crystals containing 100% of the total crystal phase is 20% or less, and the proportion of particles having a particle size of 5 to 30 nm is 60% or more. Succeeded in getting. This zirconia fine particle material has a unique shape of monoclinic zirconia by, for example, subjecting a simple treatment of neutralizing an aqueous solution containing a zirconium salt to obtain a precipitate and conducting a hydrothermal reaction under milder conditions. We have developed a technology that can be obtained as nanoparticles and can also be used as a carrier for catalysts with excellent performance, and found that the above problems can be solved. That is, the present invention includes the following zirconia fine particle materials, gas treatment catalysts, aqueous solutions or colloidal solutions, and methods for producing these.
　項１．ジルコニア微粒子材料であって、以下の（１）又は（２）：
（１）全結晶相を１００％として含有する単斜晶の割合が１０％以下であり、
平均粒子径が２０ｎｍ以下であり、且つ、
全結晶を１００％として含有する単結晶の割合が９０％以上である正方晶ジルコニア微粒子材料であるか、又は
（２）全結晶相を１００％として含有する正方晶の割合が２０％以下であり、
平均粒子径が５～３０ｎｍである単斜晶ジルコニア微粒子材料である、
のいずれかを満たす、ジルコニア微粒子材料。 Item 1. It is a zirconia fine particle material and has the following (1) or (2):
(1) The proportion of monoclinic crystals containing 100% of the total crystal phase is 10% or less.
The average particle size is 20 nm or less, and
It is a tetragonal zirconia fine particle material in which the proportion of single crystals containing 100% of all crystals is 90% or more, or (2) the proportion of tetragonal crystals containing 100% of all crystal phases is 20% or less. ,
A monoclinic zirconia fine particle material having an average particle size of 5 to 30 nm.
Zirconia fine particle material that meets any of the above.
　項２．前記（１）を満たす、項１に記載のジルコニア微粒子材料。 Item 2. Item 2. The zirconia fine particle material according to Item 1, which satisfies the above (1).
　項３．全結晶相を１００％として含有する単斜晶の割合が５％以下である、項２に記載のジルコニア微粒子材料。 Item 3. Item 2. The zirconia fine particle material according to Item 2, wherein the proportion of monoclinic crystals containing 100% of the total crystal phase is 5% or less.
　項４．平均粒子径が０．１～１０ｎｍである、項２又は３に記載のジルコニア微粒子材料。 Item 4. Item 2. The zirconia fine particle material according to Item 2 or 3, wherein the average particle size is 0.1 to 10 nm.
　項５．平均粒子径が０．２～５ｎｍである、項２～４のいずれか１項に記載のジルコニア微粒子材料。 Item 5. Item 2. The zirconia fine particle material according to any one of Items 2 to 4, wherein the average particle size is 0.2 to 5 nm.
　項６．含有する単結晶の割合が９５％以上である、項２～５のいずれか１項に記載のジルコニア微粒子材料。 Item 6. Item 2. The zirconia fine particle material according to any one of Items 2 to 5, wherein the ratio of the single crystal contained is 95% or more.
　項７．前記（２）を満たす、項１に記載のジルコニア微粒子材料。 Item 7. Item 2. The zirconia fine particle material according to Item 1, which satisfies the above (2).
　項８．全粒子数を１００％として、厚みが３ｎｍ以下であるシート状材料の割合が５０％以上である、項７に記載のジルコニア微粒子材料。 Item 8. Item 2. The zirconia fine particle material according to Item 7, wherein the ratio of the sheet-like material having a thickness of 3 nm or less is 50% or more, where the total number of particles is 100%.
　項９．全粒子数を１００％として、不定形な形状を有する粒子の割合が６０％以上である、項７又は８に記載の単斜晶ジルコニア微粒子材料。 Item 9. Item 2. The monoclinic zirconia fine particle material according to Item 7 or 8, wherein the proportion of particles having an amorphous shape is 60% or more, where the total number of particles is 100%.
　項１０．全粒子数を１００％として、不規則な方向に複数の突起が伸びる形状を有する粒子の割合が５０％以上である、項７～９のいずれか１項に記載のジルコニア微粒子材料。 Item 10. Item 2. The zirconia fine particle material according to any one of Items 7 to 9, wherein the proportion of particles having a shape in which a plurality of protrusions extend in irregular directions is 50% or more, assuming that the total number of particles is 100%.
　項１１．項１～１０のいずれか１項に記載のジルコニア微粒子材料を含むガス処理用触媒。 Item 11. A catalyst for gas treatment containing the zirconia fine particle material according to any one of Items 1 to 10.
　項１２．前記ジルコニア微粒子材料にＰｔ、Ｐｄ、Ｒｈ、Ａｕ、Ｃｕ、Ｆｅ、Ｎｉ、Ａｇ及びＣｅから選択された金属、前記金属を含む合金、並びに前記金属の酸化物よりなる群から選ばれる少なくとも１種の微粒子を担持する、項１１に記載のガス処理用触媒。 Item 12. At least one selected from the group consisting of a metal selected from Pt, Pd, Rh, Au, Cu, Fe, Ni, Ag and Ce, an alloy containing the metal, and an oxide of the metal in the zirconia fine particle material. Item 2. The gas treatment catalyst according to Item 11, which carries fine particles.
　項１３．項１～１０のいずれか１項に記載の正方晶ジルコニア微粒子材料、又は項１１若しくは１２に記載のガス処理用触媒を含有する、水溶液又はコロイド溶液。 Item 13. An aqueous solution or a colloidal solution containing the tetragonal zirconia fine particle material according to any one of Items 1 to 10 or the gas treatment catalyst according to Item 11 or 12.
　項１４．項７～１０のいずれか１項に記載のジルコニア微粒子材料、又は項１１若しくは１２に記載のガス処理用触媒を含有する、ジルコニアナノシート材料。 Item 14. The zirconia nanosheet material containing the zirconia fine particle material according to any one of Items 7 to 10 or the gas treatment catalyst according to Item 11 or 12.
　項１５．項２～６のいずれか１項に記載のジルコニア微粒子材料、項１１若しくは１２に記載のガス処理用触媒、又は項１３に記載の水溶液又はコロイド溶液の製造方法であって、
水溶性ジルコニウム塩及び水溶性界面活性剤を含む水溶液をアルカリ性として沈殿物含有水溶液を得る第１工程と、
前記沈殿物含有水溶液を９０℃～１７０℃で加熱する第２工程と、
を備える、製造方法。 Item 15. Item 2. The method for producing a zirconia fine particle material according to any one of Items 2 to 6, the gas treatment catalyst according to Item 11 or 12, or the aqueous solution or colloidal solution according to Item 13.
The first step of obtaining a precipitate-containing aqueous solution by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline.
The second step of heating the precipitate-containing aqueous solution at 90 ° C. to 170 ° C.
A manufacturing method.
　項１６．前記第２工程における加熱保持時間が１０分以上２４時間以下である、項１５に記載の製造方法。 Item 16. Item 2. The production method according to Item 15, wherein the heating holding time in the second step is 10 minutes or more and 24 hours or less.
　項１７．項７～１０のいずれか１項に記載の単斜晶ジルコニア微粒子材料、項１１若しくは１２に記載のガス処理用触媒、項１３に記載の水溶液若しくはコロイド溶液、又は項１４に記載のジルコニアナノシート材料の製造方法であって、
水溶性ジルコニウム塩及び水溶性界面活性剤を含む水溶液をアルカリ性として沈殿物含有水溶液を得る第１工程と、
前記沈殿物含有水溶液を１８０℃～６００℃で１２時間以上加熱する第２工程と、
を備える、製造方法。 Item 17. Item 7. Monoclinic zirconia fine particle material according to any one of Items 7 to 10, gas treatment catalyst according to Item 11 or 12, aqueous solution or colloidal solution according to Item 13, or zirconia nanosheet material according to Item 14. It is a manufacturing method of
The first step of obtaining a precipitate-containing aqueous solution by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline.
The second step of heating the precipitate-containing aqueous solution at 180 ° C. to 600 ° C. for 12 hours or more, and
A manufacturing method.
　項１８．前記第２工程の後、
該水溶液内の固形分を分離後、有機溶媒に分散させることで前記コロイド溶液を得る第３工程
を備える、項１５～１７のいずれか１項に記載の製造方法。 Item 18. After the second step,
Item 6. The production method according to any one of Items 15 to 17, further comprising a third step of obtaining the colloidal solution by separating the solid content in the aqueous solution and then dispersing it in an organic solvent.
　項１９．前記第２工程又は第３工程の後、溶液の溶媒を除去することで前記ジルコニア微粒子材料又は前記ガス処理用触媒を得る、項１５～１８のいずれか１項に記載の製造方法。 Item 19. The production method according to any one of Items 15 to 18, wherein the zirconia fine particle material or the catalyst for gas treatment is obtained by removing the solvent of the solution after the second step or the third step.
　項２０．前記第２工程又は第３工程の後、溶液を基板上に添加又は溶液内に基板を浸漬し取り出すことで前記ジルコニアナノシート材料を得る、項１５～１８のいずれか１項に記載の製造方法。 Item 20. Item 2. The production method according to any one of Items 15 to 18, wherein after the second step or the third step, the zirconia nanosheet material is obtained by adding a solution onto a substrate or immersing the substrate in the solution and taking it out.
　本発明の正方晶ジルコニア微粒子材料は、単結晶状の正方晶の無添加ジルコニアナノ粒子であり、特に高活性をもたらそうとする触媒材料の開発、ガス処理に有効な触媒担体やセラミックス原料として有用であり、正方晶ナノ粒子ジルコニアの応用に関する範囲を大幅に広げることができる。また、本発明の単斜晶ジルコニア微粒子材料は、全結晶相を１００％として含有する正方晶の割合が２０％以下であり、粒径が５～３０ｎｍの粒子の割合が６０％以上である。この本発明の単斜晶ジルコニア微粒子材料は、厚みが３ｎｍ以下のシート状材料とすることも、不定形な形状を有する粒子とすることも可能である。この単斜晶ジルコニア微粒子材料は、特に高活性をもたらそうとする触媒材料の開発、ガス処理に有効な触媒担体やセラミックス原料として有用であり、特異形態のナノ粒子ジルコニアの応用に関する範囲を大幅に広げることができる。 The tetragonal zirconia fine particle material of the present invention is a single crystal tetragonal additive-free zirconia nanoparticles, and is used as a catalyst carrier or a ceramic raw material effective for the development of a catalyst material to bring about particularly high activity and gas treatment. It is useful and can greatly expand the scope of application of tetragonal nanoparticles zirconia. Further, in the monoclinic zirconia fine particle material of the present invention, the proportion of tetragonal crystals containing 100% of the total crystal phase is 20% or less, and the proportion of particles having a particle size of 5 to 30 nm is 60% or more. The monoclinic zirconia fine particle material of the present invention can be a sheet-like material having a thickness of 3 nm or less, or particles having an irregular shape. This monoclinic zirconia fine particle material is particularly useful as a catalyst carrier and a ceramic raw material effective for the development of a catalyst material that is intended to bring about high activity and gas treatment, and greatly expands the range of application of the specific form of nanoparticle zirconia. Can be expanded to.
本発明（実施例１）の正方晶ジルコニア微粒子材料（１００℃）の固体状態における透過電子顕微鏡像である。It is a transmission electron microscope image in a solid state of the tetragonal zirconia fine particle material (100 degreeC) of this invention (Example 1). 本発明（実施例１）の正方晶ジルコニア微粒子材料（１００℃）の固体状態における粒径分布である。It is a particle size distribution in a solid state of the tetragonal zirconia fine particle material (100 ° C.) of this invention (Example 1). 本発明（実施例４）の正方晶ジルコニア微粒子材料（１６０℃）の固体状態における透過電子顕微鏡像である。It is a transmission electron microscope image in a solid state of the tetragonal zirconia fine particle material (160 ° C.) of this invention (Example 4). 本発明（実施例４）の正方晶ジルコニア微粒子材料（１６０℃）の固体状態における粒径分布である。It is a particle size distribution in a solid state of the tetragonal zirconia fine particle material (160 ° C.) of this invention (Example 4). 実施例１～４及び比較例１のジルコニア微粒子材料のＸ線回折図形である。5 is an X-ray diffraction pattern of the zirconia fine particle material of Examples 1 to 4 and Comparative Example 1. 実施例１～４及び比較例１のジルコニア微粒子材料（６００℃焼成後）のＸ線回折図形である。5 is an X-ray diffraction pattern of the zirconia fine particle material (after firing at 600 ° C.) of Examples 1 to 4 and Comparative Example 1. 本発明（実施例１２及び１３）の単斜晶ジルコニア微粒子材料（２００℃）のＸ線回折図形である。6 is an X-ray diffraction pattern of the monoclinic zirconia fine particle material (200 ° C.) of the present invention (Examples 12 and 13). 本発明（実施例１３）の単斜晶ジルコニア微粒子材料（２００℃４８時間）の固体状態における透過電子顕微鏡像である。It is a transmission electron microscope image in a solid state of the monoclinic zirconia fine particle material (200 degreeC 48 hours) of this invention (Example 13). 本発明（実施例１３）の単斜晶ジルコニア微粒子材料（２００℃４８時間）の固体状態における粒径分布であるIt is a particle size distribution in the solid state of the monoclinic zirconia fine particle material (200 ° C. for 48 hours) of the present invention (Example 13). 本発明（実施例１４）のジルコニアナノ粒子材料（２００℃４８時間）のSi単結晶板上に担持した後の固体状態における原子間力顕微鏡像と高さ計測結果である。It is an atomic force microscope image and a height measurement result in a solid state after supporting the zirconia nanoparticle material (200 degreeC 48 hours) of this invention (Example 14) on a Si single crystal plate.
　本明細書において、「含有」は、「含む（comprise）」、「実質的にのみからなる（consist essentially of）」、及び「のみからなる（consist of）」のいずれも包含する概念である。また、本明細書において、数値範囲を「Ａ～Ｂ」で示す場合、Ａ以上Ｂ以下を意味する。 In the present specification, "contains" is a concept that includes any of "comprise", "consist essentially of", and "consist of". Further, in the present specification, when the numerical range is indicated by "A to B", it means A or more and B or less.
　本発明は、以下の実施形態に限定されるものではなく、発明の範囲を逸脱しない限りにおいて、変更、修正、改良を加え得るものである。 The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be made without departing from the scope of the invention.
　本発明のジルコニア微粒子材料は、以下の（１）又は（２）：
（１）全結晶相を１００％として含有する単斜晶の割合が１０％以下であり、
平均粒子径が２０ｎｍ以下であり、且つ、
全結晶を１００％として含有する単結晶の割合が９０％以上である正方晶ジルコニア微粒子材料であるか、又は
（２）全結晶相を１００％として含有する正方晶の割合が２０％以下であり、
平均粒子径が５～３０ｎｍである単斜晶ジルコニア微粒子材料である、
のいずれかを満たす。 The zirconia fine particle material of the present invention has the following (1) or (2):
(1) The proportion of monoclinic crystals containing 100% of the total crystal phase is 10% or less.
The average particle size is 20 nm or less, and
It is a tetragonal zirconia fine particle material in which the proportion of single crystals containing 100% of all crystals is 90% or more, or (2) the proportion of tetragonal crystals containing 100% of all crystal phases is 20% or less. ,
A monoclinic zirconia fine particle material having an average particle size of 5 to 30 nm.
Satisfy either.
　１．正方晶ジルコニア微粒子材料、並びにその水溶液及びコロイド溶液
　本発明は、第一に、正方晶ジルコニア微粒子材料であって、全結晶相を１００％として含有する単斜晶の割合が１０％以下であり、平均粒子径が２０ｎｍ以下であり、全結晶を１００％として単結晶の割合が９０％以上である、正方晶ジルコニア微粒子材料である。 1. 1. Tetragonal zirconia fine particle material, and its aqueous solution and colloidal solution First, the present invention is a tetragonal zirconia fine particle material in which the proportion of monoclinic crystals containing 100% of the total crystal phase is 10% or less. It is a tetragonal zirconia fine particle material having an average particle size of 20 nm or less and a ratio of single crystals of 90% or more with all crystals as 100%.
　本発明の正方晶ジルコニア微粒子材料は、他の元素（ジルコニウム及び酸素以外の元素）を積極的に添加しない状態で正方晶をもつジルコニア微粒子とすることができる。本発明の正方晶ジルコニア微粒子材料で正方晶ならびに正方晶内に原子の変位を異なる状態を持つ結晶や、さらには欠陥を有しその欠陥は無秩序あるいは秩序をもって分布するかは問わない。本発明の正方晶ジルコニア微粒子材料は、平均粒子径が２０ｎｍ以下という特に小さい結晶であるため、いわゆる従来の大型単結晶や焼成したセラミックスでの温度と相の関係が成立しないことが予想される。 The tetragonal zirconia fine particle material of the present invention can be zirconia fine particles having tetragonal crystals without positively adding other elements (elements other than zirconium and oxygen). It does not matter whether the tetragonal zirconia fine particle material of the present invention has a tetragonal crystal or a crystal having different atomic displacements in the tetragonal crystal, or has a defect and the defect is distributed in a disordered or ordered manner. Since the tetragonal zirconia fine particle material of the present invention is a particularly small crystal having an average particle diameter of 20 nm or less, it is expected that the relationship between the temperature and the phase of the so-called conventional large single crystal or fired ceramics will not be established.
　なお、ジルコニア（ＺｒＯ２）には次のような構造相転移があることが知られている。すなわち、室温で安定な単斜晶から約１１７０℃で正方晶に、さらには約２２００℃で立方晶に変化する。また、室温で準安定相として正方晶があるときには、応力等で誘起された無拡散型の相転移により単斜晶に変化するとされている。これまでに室温付近で比較的な純粋なＺｒＯ２で立方晶が生成したという例はないと考えられる。Ｘ線回折（ＸＲＤ）で十分な解析を行わず、見掛けの回折線パターンのみで立方晶として説明されている場合であっても、ラマン分光法によらなければ正方晶と立方晶の区別がつかず、さらには、ＸＲＤでの判別が困難であることに配慮しない誤った研究報告がみられ、査読付き研究論文に記載があるとの理由で先行例があるとする判断にはしばしば注意を要するものである。本来、正方晶と立方晶の区別は、その構造上のｃ軸、ａ軸方向の単位胞の（００１）面間隔（ｃ）、（１００）面間隔（ａ）から、ｃ／ａが１のとき立方晶、１より大きいとき正方晶とするのが正確な表現となる。また、酸素の変位のみを考慮する正方晶も考えらえる。しかし、各回折線が幅広でその回折角度（面間隔）の測定誤差が、ｃ／ａ比の相による違いの値を超える場合には、このような測定法が適応できない。本発明では、その粒径が従来知られていない程度にきわめて小さい材料となっており、ｃ／ａの測定がさらに困難であったのが実情である。一方、単斜晶との区別は比較的容易であり、その残部がブロードな立方晶又は正方晶類似の回折線を示すと判断されることから、単斜晶量が少ないことをもって準安定な正方晶の存在量とすることができる。したがって、本発明での正方晶との記述において立方晶の混在を拒むものではない。しかしながら、２２００℃以上という極めて高温で安定な相が、室温付近及び本発明で説明される温和な条件で存在するとは推察できない。すでに知られている室温付近及び温和な条件での正方晶と単斜晶の混在の事実をもって、すなわち技術的には既知の知識の援用により、本発明においては、単斜晶の残部を正方晶として記載している。 It is known that zirconia (ZrO 2 ) has the following structural phase transitions. That is, it changes from a monoclinic crystal stable at room temperature to a tetragonal crystal at about 1170 ° C. and further to a cubic crystal at about 2200 ° C. Further, when there is a tetragonal crystal as a metastable phase at room temperature, it is said that it changes to a monoclinic crystal due to a non-diffusion type phase transition induced by stress or the like. It is considered that there has been no example of cubic crystals formed by comparatively pure ZrO 2 near room temperature. Even if X-ray diffraction (XRD) is not sufficiently analyzed and only the apparent diffraction line pattern is explained as cubic, it is possible to distinguish between tetragonal and cubic without Raman spectroscopy. Furthermore, it is often necessary to pay attention to the judgment that there is a precedent because there are erroneous research reports that do not consider the difficulty of discrimination by XRD and they are described in peer-reviewed research papers. It is a thing. Originally, the distinction between a tetragonal crystal and a cubic crystal is that c / a is 1 from the (001) plane spacing (c) and (100) plane spacing (a) of the unit cells in the c-axis and a-axis directions in the structure. The correct expression is when it is cubic, and when it is larger than 1, it is tetragonal. Also, a tetragonal crystal that considers only the displacement of oxygen can be considered. However, when each diffraction line is wide and the measurement error of the diffraction angle (plane spacing) exceeds the value of the difference due to the phase of the c / a ratio, such a measurement method cannot be applied. In the present invention, the particle size of the material is extremely small to the extent that it has not been known so far, and it is a fact that it is more difficult to measure c / a. On the other hand, it is relatively easy to distinguish it from monoclinic crystals, and it is judged that the rest shows broad cubic or tetragonal-like diffraction lines. Therefore, a small amount of monoclinic crystals is a metastable square. It can be the abundance of crystals. Therefore, the description of tetragonal crystals in the present invention does not reject the mixture of cubic crystals. However, it cannot be inferred that a phase stable at an extremely high temperature of 2200 ° C. or higher exists near room temperature and under the mild conditions described in the present invention. With the fact of the mixture of tetragonal and monoclinic crystals at around room temperature and in mild conditions, which is already known, that is, with the help of technically known knowledge, in the present invention, the rest of the monoclinic crystal is tetragonal. It is described as.
　本発明の正方晶ジルコニア微粒子材料は、全結晶相を１００％として単斜晶の存在割合が１０％以下（０～１０％）、好ましくは５％以下（０～５％）である。単斜晶の存在割合が１０％をこえると十分な触媒活性が得られない。このため、本発明の正方晶ジルコニア微粒子材料において、正方晶の存在割合は、全結晶相を１００％として９０％以上（９０～１００％）が好ましく、９５％以上（９５～１００％）がより好ましい。単斜晶の存在割合が１０％以下であることは、該正方晶ジルコニア微粒子材料のなかで，室温付近で安定な構造の相が非常に少ない材料であることを指している。異なる結晶相（特に正方晶）のジルコニアが共存することはＸ線回折図形において説明される。具体的には、Ｘ線回折図形において明確に示されるピークから検出される結晶相のうち、単斜晶の存在割合は１０％以下（特に５％以下）が好ましく、正方晶の存在割合は９０％以上（特に９５％以上）が好ましい。 The tetragonal zirconia fine particle material of the present invention has a monoclinic crystal abundance ratio of 10% or less (0 to 10%), preferably 5% or less (0 to 5%), with the total crystal phase as 100%. If the abundance ratio of monoclinic crystals exceeds 10%, sufficient catalytic activity cannot be obtained. Therefore, in the tetragonal zirconia fine particle material of the present invention, the abundance ratio of tetragonal crystals is preferably 90% or more (90 to 100%), more preferably 95% or more (95 to 100%), with the total crystal phase as 100%. preferable. The abundance ratio of monoclinic crystals of 10% or less means that among the tetragonal zirconia fine particle materials, there are very few phases having a stable structure near room temperature. The coexistence of zirconia in different crystalline phases (particularly tetragonal) is explained in the X-ray diffraction pattern. Specifically, among the crystal phases detected from the peaks clearly shown in the X-ray diffraction pattern, the abundance ratio of monoclinic crystals is preferably 10% or less (particularly 5% or less), and the abundance ratio of tetragonal crystals is 90. % Or more (particularly 95% or more) is preferable.
　本発明の正方晶ジルコニア微粒子材料は、平均粒子径が２０ｎｍ以下、好ましくは０．１～１０ｎｍ、より好ましくは０．２～５ｎｍである。平均粒子径が２０ｎｍをこえると、十分に微細化することができず十分な触媒活性が得られない。また、同様に、本発明の正方晶ジルコニア微粒子材料は、粒子径が１０ｎｍ以下の存在割合が９０％以上（９０～１００％）であることが好ましく、粒子径が５ｎｍ以下の存在割合が９５％以上（９５～１００％）であることが好ましい。本発明の正方晶ジルコニア微粒子材料は、全結晶を１００％として含有する単結晶の割合が９０％以上（９０～１００％）、好ましくは９５％以上（９５～１００％）である。単結晶の割合が９０％未満では、単結晶の割合が少なく十分な触媒活性が得られない。また、平均粒子径が２０ｎｍ以下であり、単結晶の存在割合が９０％以上である微粒子材料であることは、固体状態においては、透過型電子顕微鏡法によって粒子の大きさを調べることによって直接的に判別する。粒子は１つ１つが独立した状態で存在して、その粒径を計測すれば、単結晶であることを判別することができる。場合により、Ｘ線回折で測定される結晶子径が参照されるが、電子顕微鏡法での粒子が独立した大きさにおいて結晶子径と一致するようであれば、これらの独立粒子が単結晶であると認識してよい。さらに、溶液中のコロイドにあっては、マルバーン製ゼータサイザーナノＳを用いた動的光散乱法により、その分散状態を判別し、平均粒子径を算出する。なお、本発明において、平均粒子径とは、固体状態においては電子顕微鏡像において、ｉｍａｇｅＪを用いて個々の粒子の円相当径から算出した面積長さ平均径を意味し、溶液中のコロイドにあっては動的光散乱法により算出する拡散係数相当径であり、散乱光強度基準により測定される平均粒子径を意味する。なお、粒子形状は電子顕微鏡によってのみ明らかに観察され、平均粒子径の測定方法による多少の違いはやむを得ない。 The tetragonal zirconia fine particle material of the present invention has an average particle diameter of 20 nm or less, preferably 0.1 to 10 nm, and more preferably 0.2 to 5 nm. If the average particle size exceeds 20 nm, it cannot be sufficiently miniaturized and sufficient catalytic activity cannot be obtained. Similarly, in the tetragonal zirconia fine particle material of the present invention, the abundance ratio of the particle diameter of 10 nm or less is preferably 90% or more (90 to 100%), and the abundance ratio of the particle diameter of 5 nm or less is 95%. The above (95 to 100%) is preferable. In the tetragonal zirconia fine particle material of the present invention, the proportion of single crystals containing 100% of all crystals is 90% or more (90 to 100%), preferably 95% or more (95 to 100%). If the proportion of single crystals is less than 90%, the proportion of single crystals is small and sufficient catalytic activity cannot be obtained. Further, the fact that the fine particle material has an average particle diameter of 20 nm or less and a single crystal abundance ratio of 90% or more can be directly determined by examining the particle size by a transmission electron microscope in a solid state. To determine. Each particle exists in an independent state, and if the particle size is measured, it can be determined that the particle is a single crystal. In some cases, the crystallite diameter measured by X-ray diffraction is referred to, but if the particles in electron microscopy match the crystallite diameter in independent size, then these independent particles are single crystals. You may recognize that there is. Further, for the colloid in the solution, the dispersion state is determined by the dynamic light scattering method using the Zetasizer Nano S manufactured by Malvern, and the average particle size is calculated. In the present invention, the average particle size means the average area length average diameter calculated from the circle equivalent diameter of each particle using imageJ in the electron microscope image in the solid state, and is found in the colloid in the solution. Is the diameter equivalent to the diffusion coefficient calculated by the dynamic light scattering method, and means the average particle diameter measured by the scattered light intensity standard. The particle shape is clearly observed only by an electron microscope, and it is unavoidable that there is a slight difference depending on the method of measuring the average particle size.
　本発明の正方晶ジルコニア微粒子材料は、後述の製造方法であれば、別の元素（ジルコニウム及び酸素以外の元素）を含まない状態で得ることができる。つまり、本発明の正方晶ジルコニア微粒子材料は、他の元素を含まない無添加ジルコニアナノ粒子とすることもできる。 The tetragonal zirconia fine particle material of the present invention can be obtained in a state of not containing another element (elements other than zirconium and oxygen) by the production method described later. That is, the tetragonal zirconia fine particle material of the present invention can also be additive-free zirconia nanoparticles containing no other element.
　一方、本発明の正方晶ジルコニア微粒子材料には、不純物元素を含むこともできる。具体的には、本発明の正方晶ジルコニア微粒子材料があらかじめジルコニア以外の金属、例えば白金、ロジウム、パラジウム、金、銀等の貴金属；Ｃｕ、Ｆｅ、Ｎｉ等の遷移金属；希土類元素；アルカリ土類金属等の１種又は２種以上の金属を含んでいてもよい。希土類金属としては、イットリウム、スカンジウム、ランタン、プラセオジム、ネオジム、プロメチウム、サマリウム、ユーロピウム、ガドリニウム、テルビウム、ジスプロシウム、ホルミウム、エルビウム、ツリウム、イッテルビウム、ルテチウム等が挙げられる。なかでも、触媒活性の観点からは、貴金属や、遷移金属、さらにはランタン（Ｌａ）、ネオジム（Ｎｄ）、プラセオジム（Ｐｒ）、イットリウム（Ｙ）等を単独もしくは混合状態で、ジルコニア粒子と共存して含むことがより好ましい。これらは、混合状態であって結晶相に影響するいわゆる固溶状態ではないことが好ましいが、固溶が少ない場合には性能上で問題はない。このような不純物元素を含む場合、その含有量は、本発明の正方晶ジルコニア微粒子材料の総量を１００質量％として、２質量％以下が好ましい。 On the other hand, the tetragonal zirconia fine particle material of the present invention can also contain an impurity element. Specifically, the square zirconia fine particle material of the present invention is a metal other than zirconia, for example, a noble metal such as platinum, rhodium, palladium, gold, silver; a transition metal such as Cu, Fe, Ni; a rare earth element; an alkaline earth. It may contain one kind or two or more kinds of metals such as metal. Examples of rare earth metals include ytterbium, scandium, lantern, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and the like. Among them, from the viewpoint of catalytic activity, precious metals, transition metals, lanthanum (La), neodymium (Nd), praseodymium (Pr), yttrium (Y), etc. coexist with zirconia particles alone or in a mixed state. It is more preferable to include. It is preferable that these are in a mixed state and not in a so-called solid solution state that affects the crystal phase, but there is no problem in performance when the solid solution is small. When such an impurity element is contained, the content thereof is preferably 2% by mass or less, with the total amount of the tetragonal zirconia fine particle material of the present invention being 100% by mass.
　上記した本発明の正方晶ジルコニア微粒子材料の形態は特に制限はなく、粉末状態でもよいが、水溶液又はコロイド溶液とすることもできる。具体的には、後述の製造方法において、水熱反応直後は水溶液として得ることができ、その後有機溶媒に分散させた場合にはコロイド溶液として得ることができる。 The form of the tetragonal zirconia fine particle material of the present invention described above is not particularly limited and may be in a powder state, but may be an aqueous solution or a colloidal solution. Specifically, in the production method described later, it can be obtained as an aqueous solution immediately after the hydrothermal reaction, and then as a colloidal solution when dispersed in an organic solvent.
　コロイド溶液を採用する場合に使用できる有機溶媒は、非極性溶媒が好ましく、トルエン、ベンゼン、石油エーテル、シクロヘキサン、ヘプタン、ドデカン、シクロヘキセン、メシチレン（1,3,5-トリメチルベンゼン）、エチルベンゼン、ジュレン（1,2,4,5-テトラメチルベンゼン）、ジエチルエーテル等が挙げられる。また、テトラクロロメタン、クロロホルム、クロロベンゼン、ジクロロベンゼン等も使用することができる。また、極性溶媒を使用こともでき、プロパノール、エタノール等アルコール類、アセトン等のケトン類、ジメチルスルホキシド、テトラヒドロフランやジメチルホルムアミド等を使用してもよい。 The organic solvent that can be used when the colloidal solution is adopted is preferably a non-polar solvent, such as toluene, benzene, petroleum ether, cyclohexane, heptane, dodecane, cyclohexene, mesitylene (1,3,5-trimethylbenzene), ethylbenzene, and jurene (1,3,5-trimethylbenzene). 1,2,4,5-Tetramethylbenzene), diethyl ether and the like. Further, tetrachloromethane, chloroform, chlorobenzene, dichlorobenzene and the like can also be used. Further, a polar solvent may be used, and alcohols such as propanol and ethanol, ketones such as acetone, dimethyl sulfoxide, tetrahydrofuran, dimethylformamide and the like may be used.
　上記した本発明の正方晶ジルコニア微粒子材料を水溶液又はコロイド溶液とする場合、本発明の正方晶ジルコニア微粒子材料の濃度は特に制限されず、例えば、０．０００１～４０質量％、特に０．０１～１０質量％とすることができる。 When the tetragonal zirconia fine particle material of the present invention is used as an aqueous solution or a colloidal solution, the concentration of the tetragonal zirconia fine particle material of the present invention is not particularly limited, and is, for example, 0.0001 to 40% by mass, particularly 0.01 to. It can be 10% by mass.
　２．単斜晶ジルコニア微粒子材料、並びにその水溶液、コロイド溶液及びジルコニアナノシート材料
　本発明は、第二に、単斜晶ジルコニア微粒子材料であって、全結晶相を１００％として含有する正方晶の割合が２０％以下であり、平均粒子径が５～３０ｎｍである、単斜晶ジルコニア微粒子材料である。 2. 2. Monoclinic zirconia fine particle material, and its aqueous solution, colloidal solution and zirconia nanosheet material The present invention is secondly a monoclinic zirconia fine particle material in which the proportion of square crystals containing 100% of the total crystal phase is 20. A monoclinic zirconia fine particle material having an average particle size of 5 to 30 nm or less.
　本発明の単斜晶ジルコニア微粒子材料は、他の元素（ジルコニウム及び酸素以外の元素）を積極的に添加しない状態で単斜晶をもつジルコニア微粒子とすることができ、シート形状を有することも特異形状を有することもできる。 The monoclinic zirconia fine particle material of the present invention can be made into zirconia fine particles having monoclinic crystals without actively adding other elements (elements other than zirconium and oxygen), and it is also peculiar to have a sheet shape. It can also have a shape.
　本発明の単斜晶ジルコニア微粒子材料は、全結晶相を１００％として正方晶の存在割合が２０％以下（０～２０％）、好ましくは１０％以下（０～１０％）である。正方晶の存在割合が２０％をこえると、触媒担体として高活性が期待されるシート形状や特異形状を有するジルコニア微粒子を得ることができない。このため、本発明の単斜晶ジルコニア微粒子材料において、単斜晶の存在割合は、全結晶相を１００％として８０％以上（８０～１００％）が好ましく、９０％以上（９０～１００％）がより好ましい。正方晶の存在割合が２０％以下であることは、該単斜晶ジルコニア微粒子材料のなかで，室温付近で安定な構造の相が多い材料であることを指している。異なる結晶相（特に正方晶）のジルコニアが共存することはＸ線回折図形において説明される。具体的には、Ｘ線回折図形において明確に示されるピークから検出される結晶相のうち、正方晶の存在割合は２０％以下（特に１０％以下）が好ましく、単斜晶の存在割合は８０％以上（特に９０％以上）が好ましい。 The monoclinic zirconia fine particle material of the present invention has a tetragonal abundance ratio of 20% or less (0 to 20%), preferably 10% or less (0 to 10%), with the total crystal phase as 100%. If the abundance ratio of tetragonal crystals exceeds 20%, zirconia fine particles having a sheet shape or a peculiar shape expected to have high activity as a catalyst carrier cannot be obtained. Therefore, in the monoclinic zirconia fine particle material of the present invention, the abundance ratio of monoclinic crystals is preferably 80% or more (80 to 100%), and 90% or more (90 to 100%), with the total crystal phase as 100%. Is more preferable. The fact that the abundance ratio of tetragonal crystals is 20% or less means that among the monoclinic zirconia fine particle materials, there are many phases having a stable structure near room temperature. The coexistence of zirconia in different crystalline phases (particularly tetragonal) is explained in the X-ray diffraction pattern. Specifically, among the crystal phases detected from the peaks clearly shown in the X-ray diffraction pattern, the abundance ratio of tetragonal crystals is preferably 20% or less (particularly 10% or less), and the abundance ratio of monoclinic crystals is 80. % Or more (particularly 90% or more) is preferable.
　本発明の単斜晶ジルコニア微粒子材料は、平均粒子径が５～３０ｎｍ、好ましくは１０～２５ｎｍである。平均粒子径が３０ｎｍをこえると、十分に微細化することができず十分な触媒活性が得られない。また、平均粒子径が５ｎｍ未満の単斜晶ジルコニア微粒子材料を得ることは困難である。また、平均粒子径が５～３０ｎｍであることは、固体状態においては、透過型電子顕微鏡法によって粒子の大きさを調べることによって直接的に判別する。粒子は１つ１つが独立した状態で存在して、その粒径を計測すれば判別することができる。場合により、Ｘ線回折で測定される結晶子径が参照されるが、電子顕微鏡法での粒子が独立した大きさにおいて結晶子径と一致するようであれば、これらの独立粒子が単結晶であると認識してよい。さらに、溶液中のコロイドにあっては、マルバーン製ゼータサイザーナノＳを用いた動的光散乱法により、その分散状態を判別し、平均粒子径を算出する。本発明の単斜晶ジルコニア微粒子材料は、平均粒子径が５～３０ｎｍという特に小さい結晶であるため、いわゆる従来の大型単結晶や焼成したセラミックスでの温度と相の関係が成立しないことが予想される。なお、本発明において、平均粒子径とは、固体状態においては電子顕微鏡像において、ｉｍａｇｅＪを用いて個々の粒子の円相当径から算出した面積長さ平均径を意味し、溶液中のコロイドにあっては動的光散乱法により算出する拡散係数相当径であり、散乱光強度基準により測定される平均粒子径を意味する。なお、粒子形状は電子顕微鏡によってのみ明らかに観察され、平均粒子径の測定方法による多少の違いはやむを得ない。 The monoclinic zirconia fine particle material of the present invention has an average particle diameter of 5 to 30 nm, preferably 10 to 25 nm. If the average particle size exceeds 30 nm, it cannot be sufficiently miniaturized and sufficient catalytic activity cannot be obtained. Further, it is difficult to obtain a monoclinic zirconia fine particle material having an average particle diameter of less than 5 nm. Further, the fact that the average particle diameter is 5 to 30 nm is directly determined by examining the particle size by a transmission electron microscope in the solid state. Each particle exists in an independent state, and can be identified by measuring its particle size. In some cases, the crystallite diameter measured by X-ray diffraction is referred to, but if the particles in electron microscopy match the crystallite diameter in independent size, then these independent particles are single crystals. You may recognize that there is. Further, for the colloid in the solution, the dispersion state is determined by the dynamic light scattering method using the Zetasizer Nano S manufactured by Malvern, and the average particle size is calculated. Since the monoclinic zirconia fine particle material of the present invention is a particularly small crystal having an average particle diameter of 5 to 30 nm, it is expected that the relationship between the temperature and the phase of the so-called conventional large single crystal or fired ceramics will not be established. To. In the present invention, the average particle size means the average area length average diameter calculated from the circle equivalent diameter of each particle using imageJ in the electron microscope image in the solid state, and is found in the colloid in the solution. Is the diameter equivalent to the diffusion coefficient calculated by the dynamic light scattering method, and means the average particle diameter measured by the scattered light intensity standard. The particle shape is clearly observed only by an electron microscope, and it is unavoidable that there is a slight difference depending on the method of measuring the average particle size.
　本発明の単斜晶ジルコニア微粒子材料は、粒子径が５～３０ｎｍの存在割合は６０％以上（６０～１００％）が好ましく、７０％以上（７０～１００％）がより好ましい。粒子径が５～３０ｎｍの存在割合が６０％以上とすることで、十分に微細化しやすく、十分な触媒活性が得られやすい。また、粒子径が５～３０ｎｍの存在割合が６０％以上である微粒子材料であることは、透過型電子顕微鏡法によって粒子の大きさを調べることによって直接的に判別する。粒子は１つ１つが独立した状態で存在して、その粒径を計測すれば判別することができる。場合により、Ｘ線回折で測定される結晶子径が参照されるが、電子顕微鏡法での粒子が独立した大きさにおいて結晶子径と一致するようであれば、これらの独立粒子が単結晶であると認識してよい。さらに、溶液中のコロイドにあっては、マルバーン製ゼータサイザーナノＳを用いた動的光散乱法により、その分散状態を判別し、粒子径が５～３０ｎｍの存在割合が６０％以上であることを確認する。 The monoclinic zirconia fine particle material of the present invention preferably has a particle size of 5 to 30 nm and an abundance ratio of 60% or more (60 to 100%), more preferably 70% or more (70 to 100%). When the abundance ratio of the particle size of 5 to 30 nm is 60% or more, it is easy to be sufficiently finely divided and sufficient catalytic activity can be easily obtained. Further, the fine particle material having a particle diameter of 5 to 30 nm and an abundance ratio of 60% or more is directly determined by examining the particle size by a transmission electron microscope method. Each particle exists in an independent state, and can be identified by measuring its particle size. In some cases, the crystallite diameter measured by X-ray diffraction is referred to, but if the particles in electron microscopy match the crystallite diameter in independent size, then these independent particles are single crystals. You may recognize that there is. Furthermore, for colloids in solution, the dispersion state is determined by a dynamic light scattering method using Zetasizer Nano S manufactured by Malvern, and the abundance ratio of a particle size of 5 to 30 nm is 60% or more. To confirm.
　次に、本発明の単斜晶ジルコニア微粒子材料はシート類似形状とすることができ、厚みが３ｎｍ以下であるシート状材料の割合を５０％以上（５０～１００％）とすることができ、厚みが２．５ｎｍ以下であるシート状材料の割合を７０％以上（７０～１００％）とすることが好ましい。このような構成を採用する場合には、異方性による特異性を有し、極薄膜材としてのデバイス用に配列可能な原料として有用である。この本発明の単斜晶ジルコニア微粒子材料の厚みについては、原子間力顕微鏡によって評価する。 Next, the monoclinic zirconia fine particle material of the present invention can have a sheet-like shape, and the proportion of the sheet-like material having a thickness of 3 nm or less can be 50% or more (50 to 100%), and the thickness can be set. The proportion of the sheet-like material having a thickness of 2.5 nm or less is preferably 70% or more (70 to 100%). When such a configuration is adopted, it has anisotropy specificity and is useful as a raw material that can be arranged for a device as an ultrathin film material. The thickness of the monoclinic zirconia fine particle material of the present invention is evaluated by an atomic force microscope.
  本発明の単斜晶ジルコニア微粒子材料は、一般に、不定形の形状を有する粒子の割合が６０％以上（特に７０％以上）であることが好ましい。すなわち、繊維状や、板状や、粒状の形状ではなく、不規則な形状を有する粒子の割合が５０％以上（特に６０％以上）であることが好ましい。具体的には、不規則な方向に複数の突起が延びる形状を有する粒子の割合が５０％以上（特に６０％以上）であることが好ましく、隣り合う突起の先端と単斜晶ジルコニア微粒子材料の中心を結ぶ直線がなす角度が１８０度未満である粒子の割合が５０％以上（特に６０％以上）であることが好ましい。なお、突起は、必ずしも１つの形状ではなく、２以上の形状であってもよい。また、突起は、必ずしも細長い形状である必要はない。より好ましくは、不規則な方向に複数の突起を分岐として、分岐数が３以上である粒子の割合が４０％以上（特に４５％以上）であることが好ましい。すなわち、アメーバ状の形状や、ジグソーパズルのピースのような形状を有しているものであることが好ましい。 In the monoclinic zirconia fine particle material of the present invention, it is generally preferable that the proportion of particles having an amorphous shape is 60% or more (particularly 70% or more). That is, it is preferable that the proportion of particles having an irregular shape rather than a fibrous, plate-like, or granular shape is 50% or more (particularly 60% or more). Specifically, the proportion of particles having a shape in which a plurality of protrusions extend in irregular directions is preferably 50% or more (particularly 60% or more), and the tips of adjacent protrusions and the monoclinic zirconia fine particle material. It is preferable that the proportion of particles in which the angle formed by the straight line connecting the centers is less than 180 degrees is 50% or more (particularly 60% or more). The protrusions do not necessarily have one shape, but may have two or more shapes. Further, the protrusion does not necessarily have to have an elongated shape. More preferably, the proportion of particles having a number of branches of 3 or more is 40% or more (particularly 45% or more) by branching a plurality of protrusions in irregular directions. That is, it is preferable that it has an amoeba-like shape or a shape like a jigsaw puzzle piece.
　本発明の単斜晶ジルコニア微粒子材料は、後述の製造方法であれば、別の元素（ジルコニウム及び酸素以外の元素）を含まない状態で得ることができる。つまり、本発明の単斜晶ジルコニア微粒子材料は、他の元素を含まない無添加ジルコニアナノ粒子とすることもできる。 The monoclinic zirconia fine particle material of the present invention can be obtained in a state of not containing another element (elements other than zirconium and oxygen) by the production method described later. That is, the monoclinic zirconia fine particle material of the present invention can also be additive-free zirconia nanoparticles containing no other element.
　一方、本発明の単斜晶ジルコニア微粒子材料には、不純物元素を含むこともできる。具体的には、本発明の単斜晶ジルコニア微粒子材料があらかじめジルコニア以外の金属、例えば白金、ロジウム、パラジウム、金、銀等の貴金属；Ｃｕ、Ｆｅ、Ｎｉ等の遷移金属；希土類元素；アルカリ土類金属等の１種又は２種以上の金属を含んでいてもよい。希土類金属としては、イットリウム、スカンジウム、ランタン、プラセオジム、ネオジム、プロメチウム、サマリウム、ユーロピウム、ガドリニウム、テルビウム、ジスプロシウム、ホルミウム、エルビウム、ツリウム、イッテルビウム、ルテチウム等が挙げられる。なかでも、触媒活性の観点からは、貴金属や、遷移金属、さらにはランタン（Ｌａ）、ネオジム（Ｎｄ）、プラセオジム（Ｐｒ）、イットリウム（Ｙ）等を単独もしくは混合状態で、ジルコニア粒子と共存して含むことがより好ましい。これらは、混合状態であって結晶相に影響するいわゆる固溶状態ではないことが好ましいが、固溶が少ない場合には性能上で問題はない。このような不純物元素を含む場合、その含有量は、本発明の単斜晶ジルコニア微粒子材料の総量を１００質量％として、２質量％以下が好ましい。 On the other hand, the monoclinic zirconia fine particle material of the present invention may also contain an impurity element. Specifically, the monoclinic zirconia fine particle material of the present invention is a metal other than zirconia, for example, a precious metal such as platinum, rhodium, palladium, gold, silver; a transition metal such as Cu, Fe, Ni; a rare earth element; an alkaline soil. It may contain one kind or two or more kinds of metals such as a kind metal. Examples of rare earth metals include ytterbium, scandium, lantern, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and the like. Among them, from the viewpoint of catalytic activity, precious metals, transition metals, lanthanum (La), neodymium (Nd), praseodymium (Pr), yttrium (Y), etc. coexist with zirconia particles alone or in a mixed state. It is more preferable to include. It is preferable that these are in a mixed state and not in a so-called solid solution state that affects the crystal phase, but there is no problem in performance when the solid solution is small. When such an impurity element is contained, the content thereof is preferably 2% by mass or less, with the total amount of the monoclinic zirconia fine particle material of the present invention being 100% by mass.
　上記した本発明の単斜晶ジルコニア微粒子材料の形態は特に制限はなく、粉末状態でもよいが、水溶液又はコロイド溶液とすることもできる。具体的には、後述の製造方法において、水熱反応直後は水溶液として得ることができ、その後有機溶媒に分散させた場合にはコロイド溶液として得ることができる。 The form of the monoclinic zirconia fine particle material of the present invention described above is not particularly limited and may be in a powder state, but may be an aqueous solution or a colloidal solution. Specifically, in the production method described later, it can be obtained as an aqueous solution immediately after the hydrothermal reaction, and then as a colloidal solution when dispersed in an organic solvent.
　コロイド溶液を採用する場合に使用できる有機溶媒は、非極性溶媒が好ましく、トルエン、ベンゼン、石油エーテル、シクロヘキサン、ヘプタン、ドデカン、シクロヘキセン、メシチレン（1,3,5-トリメチルベンゼン）、エチルベンゼン、ジュレン（1,2,4,5-テトラメチルベンゼン）、ジエチルエーテル等が挙げられる。また、テトラクロロメタン、クロロホルム、クロロベンゼン、ジクロロベンゼン等も使用することができる。また、極性溶媒を使用こともでき、プロパノール、エタノール等アルコール類、アセトン等のケトン類、ジメチルスルホキシド、テトラヒドロフランやジメチルホルムアミド等を使用してもよい。 The organic solvent that can be used when the colloidal solution is adopted is preferably a non-polar solvent, such as toluene, benzene, petroleum ether, cyclohexane, heptane, dodecane, cyclohexene, mesitylene (1,3,5-trimethylbenzene), ethylbenzene, and jurene (1,3,5-trimethylbenzene). 1,2,4,5-Tetramethylbenzene), diethyl ether and the like. Further, tetrachloromethane, chloroform, chlorobenzene, dichlorobenzene and the like can also be used. Further, a polar solvent may be used, and alcohols such as propanol and ethanol, ketones such as acetone, dimethyl sulfoxide, tetrahydrofuran, dimethylformamide and the like may be used.
　上記した本発明の単斜晶ジルコニア微粒子材料を水溶液又はコロイド溶液とする場合、本発明の単斜晶ジルコニア微粒子材料の濃度は特に制限されず、例えば、０．０００１～４０質量％、特に０．０１～１０質量％とすることができる。 When the monoclinic zirconia fine particle material of the present invention is used as an aqueous solution or a colloidal solution, the concentration of the monoclinic zirconia fine particle material of the present invention is not particularly limited, and is, for example, 0.0001 to 40% by mass, particularly 0. It can be 01 to 10% by mass.
　また、上記した本発明の単斜晶ジルコニア微粒子材料の水溶液又はコロイド溶液を基板上に添加もしくは溶液内に基板を浸漬し取り出すことによってジルコニアナノシート材料とすることもできる。本発明の単斜晶ジルコニア微粒子材料は上記のように、厚みが３ｎｍ以下であるシート状材料の割合を５０％以上とすることができるため、全体として厚みの薄いナノシート材料とすることが可能である。この際、本発明のジルコニアナノシート材料の厚みは、０．５～５０ｎｍ（±０．３ｎｍ）が好ましく、０．５～５ｎｍ（±０．３ｎｍ）がより好ましい。 Further, the zirconia nanosheet material can also be obtained by adding the aqueous solution or colloidal solution of the monoclinic zirconia fine particle material of the present invention described above onto the substrate or immersing the substrate in the solution and taking it out. As described above, the monoclinic zirconia fine particle material of the present invention can have a sheet-like material having a thickness of 3 nm or less of 50% or more, and thus can be a nanosheet material having a thin thickness as a whole. is there. At this time, the thickness of the zirconia nanosheet material of the present invention is preferably 0.5 to 50 nm (± 0.3 nm), more preferably 0.5 to 5 nm (± 0.3 nm).
　３．ガス処理用触媒
　本発明は、第三に、上記載の正方晶ジルコニア微粒子材料又は単斜晶ジルコニア微粒子材料を含むガス処理用触媒である。 3. 3. Gas Treatment Catalyst The present invention is, thirdly, a gas treatment catalyst containing the above-mentioned tetragonal zirconia fine particle material or monoclinic zirconia fine particle material.
　ジルコニアの主要な用途として、触媒担体、特に自動車等排ガス浄化触媒材料があり、本発明のジルコニア微粒子材料を担体として含むガス処理用触媒が、とくにその有効性を発揮する。なお、本発明のジルコニア微粒子材料を使用する態様は、触媒担体として使用する場合に限定されない。例えば、公知の触媒担体（ジルコニア、希土類等が添加されたジルコニア、アルミナ、チタニア、セリア、ジルコニア含有セリア、セリア添加ジルコニア、セリアジルコニア固溶体等）を本発明のジルコニア微粒子材料で被覆することや付着させることもできる。この場合、本発明のジルコニア微粒子材料は、ガス処理用触媒の担体を被覆、付着するための添加剤又はコーティング剤として機能する。 The main use of zirconia is a catalyst carrier, especially an exhaust gas purification catalyst material for automobiles, etc., and the catalyst for gas treatment containing the zirconia fine particle material of the present invention as a carrier is particularly effective. The mode in which the zirconia fine particle material of the present invention is used is not limited to the case where it is used as a catalyst carrier. For example, a known catalyst carrier (zirconia, alumina, titania, ceria, zirconia-containing ceria, ceria-added zirconia, ceria zirconia solid solution, etc. to which zirconia, rare earths, etc. are added) is coated or adhered to the zirconia fine particle material of the present invention. You can also do it. In this case, the zirconia fine particle material of the present invention functions as an additive or a coating agent for coating and adhering the carrier of the gas treatment catalyst.
　本発明の正方晶ジルコニア微粒子材料を使用する場合、正方晶ジルコニアは単斜晶ジルコニアに比べ結晶構造の特徴から原子レベルで平坦な表面構造を維持しやすく電子的相互作用がしやすく金属触媒に対して良好な担体として働く。一方、本発明の単斜晶ジルコニア微粒子材料を使用する場合、ジルコニアがナノ粒子で、複雑形状をもつ場合はその表面に特異的に活性な部位が発現し得る。また、ナノシート状粒子にあっては、その上に金属クラスター等の特に活性な材料を一様に担持でき、有効に利用できる担体となる。結晶構造の特徴から原子レベルで平坦な表面構造を維持しやすく電子的相互作用がしやすく金属触媒対して良好な担体として働く。さらには、単斜晶は安定な構造であり、各種の応用に対してもその経時的な変化をおこしにくい。 When the tetragonal zirconia fine particle material of the present invention is used, the tetragonal zirconia has a crystal structure characteristic as compared with the monoclinic zirconia, so that it is easy to maintain a flat surface structure at the atomic level and electronic interaction is easy to occur with respect to the metal catalyst. Works as a good carrier. On the other hand, when the monoclinic zirconia fine particle material of the present invention is used, when the zirconia is nanoparticles and has a complicated shape, a site specifically active can be expressed on the surface thereof. Further, in the case of nanosheet-like particles, a particularly active material such as a metal cluster can be uniformly supported on the nanosheet-like particles, and the carrier can be effectively used. Due to the characteristics of the crystal structure, it is easy to maintain a flat surface structure at the atomic level and electronic interaction is easy, and it works as a good carrier for metal catalysts. Furthermore, the monoclinic crystal has a stable structure and is unlikely to change over time for various applications.
　本発明のジルコニア微粒子材料を使用する場合、さらに、前記ジルコニア微粒子材料に対して、Ｐｔ、Ｐｄ、Ｒｈ、Ａｕ、Ｃｕ、Ｆｅ、Ｎｉ、Ａｇ、Ｃｅ等の金属、これら金属を含む合金、これら金属の酸化物等の１種又は２種以上を担持するガス処理用触媒は、その金属状態維持に対して反応性の低いジルコニア質が有効に利用できる。特に自動車等排ガス浄化に多用されるジルコニア上担持ロジウム金属触媒による窒素酸化物浄化に関して高性能である。 When the zirconia fine particle material of the present invention is used, further, with respect to the zirconia fine particle material, metals such as Pt, Pd, Rh, Au, Cu, Fe, Ni, Ag, and Ce, alloys containing these metals, and these metals As the gas treatment catalyst carrying one or more of the oxides of the above, a zirconia substance having low reactivity with respect to maintaining the metallic state can be effectively used. In particular, it has high performance regarding nitrogen oxide purification using a rhodium metal catalyst supported on zirconia, which is often used for exhaust gas purification of automobiles.
　４．製造方法（その１）
　次に、本発明の正方晶ジルコニア微粒子材料や本発明の正方晶ジルコニア微粒子材料を含む水溶液又はコロイド溶液および微粒子の製造方法について説明する。本発明の正方晶ジルコニア微粒子材料は、上述したように正方晶ジルコニア粒子であり、本発明の製造方法によれば、それらが有機物等と複合化され微粒子が分散しているコロイド溶液として得ることもできる。 4. Manufacturing method (1)
Next, an aqueous solution or colloidal solution containing the tetragonal zirconia fine particle material of the present invention and the tetragonal zirconia fine particle material of the present invention, and a method for producing fine particles will be described. The tetragonal zirconia fine particle material of the present invention is tetragonal zirconia particles as described above, and according to the production method of the present invention, they can be obtained as a colloidal solution in which fine particles are dispersed by being composited with an organic substance or the like. it can.
　このような本発明の製造方法は、水溶性ジルコニウム塩及び水溶性界面活性剤を含む水溶液をアルカリ性として沈殿物含有水溶液を得る第１工程と、前記沈殿物含有水溶液を９０℃～１７０℃で加熱する第２工程とを備える。 Such a production method of the present invention comprises a first step of making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline to obtain a precipitate-containing aqueous solution, and heating the precipitate-containing aqueous solution at 90 ° C to 170 ° C. A second step is provided.
　水溶性ジルコニウム塩及び水溶性界面活性剤を含む水溶液をアルカリ性としてその沈殿物含有水溶液を得る第１工程において、その原料となるジルコニウム塩水溶液の作製方法そのものについては特に制限されることなく公知の方法を用いることができる。本発明で推奨する方法を述べれば、水溶性ジルコニウム塩と水溶性界面活性剤との混合水溶液を塩基で中和すると、沈殿したジルコニアが水中でゲル状とすることができる。 In the first step of obtaining an aqueous solution containing a precipitate by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline, the method itself for producing the zirconium salt aqueous solution as a raw material thereof is not particularly limited and is known. Can be used. Described in the method recommended in the present invention, when a mixed aqueous solution of a water-soluble zirconium salt and a water-soluble surfactant is neutralized with a base, the precipitated zirconia can be gelled in water.
　水溶性ジルコニウム塩としては、例えば、硝酸ジルコニウム、塩化ジルコニウム、硝酸酸化ジルコニウム、酸化ジルコニウム塩化物等を例示することができる。更に本発明でアルカリ性とするために用い得る塩基としては、例えば、アンモニア、尿素、水酸化ナトリウム、水酸化カリウム等を例示することができる。このようなジルコニアゲルの作製方法は知られており、中和して沈殿が生成するときにジルコニウムが共存していれば塩基にジルコニウム塩水溶液を加えても、またジルコニウム塩水溶液に塩基を加えてもよい。また、中和時の温度や中和時の混合時間、添加速度を変更することでその性状を変化させることもできるが、いずれの場合でも本発明に使用できる。例えば、添加する塩基の量は水溶性ジルコニム１モルに対して１～１００モルとすることができ、中和時の温度は０～９９℃とすることができ、中和時の混合時間は１分～１００時間とすることができ、添加速度は０．００１～１００ｍＬ／秒とすることができる。 Examples of the water-soluble zirconium salt include zirconium nitrate, zirconium chloride, zirconium nitrate oxide, zirconium chloride chloride and the like. Further, examples of the base that can be used to make the base alkaline in the present invention include ammonia, urea, sodium hydroxide, potassium hydroxide and the like. A method for producing such a zirconia gel is known, and if zirconium coexists when neutralized to form a precipitate, a zirconium salt aqueous solution may be added to the base, or a base may be added to the zirconium salt aqueous solution. May be good. Further, the properties can be changed by changing the temperature at the time of neutralization, the mixing time at the time of neutralization, and the addition rate, and in any case, it can be used in the present invention. For example, the amount of base to be added can be 1 to 100 mol per 1 mol of water-soluble zirconim, the temperature at the time of neutralization can be 0 to 99 ° C., and the mixing time at the time of neutralization is 1. It can be from 1 minute to 100 hours, and the addition rate can be 0.001 to 100 mL / sec.
　前記ジルコニウム塩を含む水溶液と塩基とを混合する前に、前記ジルコニウム塩と水溶性有機剤とを混合することが好ましく、水溶性有機剤としていわゆる界面活性剤を利用することが好ましい。界面活性剤としては、例えば、オレイン酸、リノール酸、ルウリン酸等の不飽和脂肪酸及びその塩（ナトリウム塩、カリウム塩等のアルカリ金属塩）；その他のカルボン酸として、飽和脂肪酸、メチルタウリン酸、スルホコハク酸及びその塩（ナトリウム塩、カリウム塩等のアルカリ金属塩）；アルキルベンゼンスルホン酸及びその塩（ナトリウム塩、カリウム塩等のアルカリ金属塩）；αオレフィンスルホン酸（テトラデセンスルホン酸等）及びその塩（ナトリウム塩、カリウム塩等のアルカリ金属塩）；アルキル硫酸エステル酸、アルキルエーテル硫酸エステル塩、フェニルエーテル硫酸エステル塩、エーテル硫酸塩、アルキル硫酸塩、エーテルスルホン酸塩等が挙げられ、分子内に親水性と疎水性の官能基をもつ有機剤であれば広く利用できる。これらは、沈殿する無機成分に吸着している状態を具現すればよいため、ミセルを形成する必要はなく、臨界ミセル濃度等、有機剤の添加濃度の制限がない。正方晶ジルコニア微粒子材料、水溶液及びコロイド溶液の製造に使用するジルコニウムの含量を原子数であらわすとき添加する有機分子数との比が０．００１から１０００の広い範囲が適用可能である。 Before mixing the aqueous solution containing the zirconium salt with the base, it is preferable to mix the zirconium salt with the water-soluble organic agent, and it is preferable to use a so-called surfactant as the water-soluble organic agent. Examples of the surfactant include unsaturated fatty acids such as oleic acid, linoleic acid and ruuric acid and salts thereof (alkali metal salts such as sodium salt and potassium salt); and other carboxylic acids include saturated fatty acids and methyl tauric acid. Sulfosuccinic acid and its salts (alkali metal salts such as sodium salt and potassium salt); alkylbenzene sulfonic acid and its salts (alkali metal salts such as sodium salt and potassium salt); α-olefin sulfonic acid (tetradecene sulfonic acid and the like) and their salts. Salts (alkali metal salts such as sodium salt and potassium salt); alkyl sulfate ester acid, alkyl ether sulfate ester salt, phenyl ether sulfate ester salt, ether sulfate salt, alkyl sulfate salt, ether sulfonate and the like can be mentioned in the molecule. Any organic agent having hydrophilic and hydrophobic functional groups can be widely used. Since these may be realized in a state of being adsorbed on the precipitated inorganic component, it is not necessary to form micelles, and there is no limitation on the concentration of the organic agent added such as the critical micelle concentration. A wide range of 0.001 to 1000 is applicable in which the ratio of the content of zirconium used in the production of tetragonal zirconia fine particle materials, aqueous solutions and colloidal solutions to the number of organic molecules added when expressed in atomic numbers is 0.001 to 1000.
　第２工程では、第１工程を経た沈殿物を含む水溶液を水熱条件に置くことに特徴を有するが９０℃～１７０℃の条件で、特に１００℃～１６０℃で、が好ましい。保持時間は特に制限されるわけではないが、１０分以上が好ましく、１時間以上がより好ましく、６時間以上がさらに好ましい。また、保持時間は２４時間以下が好ましい。容器は自然的に発生する圧力と温度に耐える状態の材質と形状が好ましいが、容器の耐久性の観点からテフロン（登録商標）等の耐腐食性材を内容器に用いることが適当である。この第２工程を経ることで、上記した本発明の水溶液を得ることができる。 The second step is characterized in that the aqueous solution containing the precipitate that has undergone the first step is placed under hydrothermal conditions, but the conditions are 90 ° C. to 170 ° C., particularly preferably 100 ° C. to 160 ° C. The holding time is not particularly limited, but is preferably 10 minutes or more, more preferably 1 hour or more, and even more preferably 6 hours or more. The holding time is preferably 24 hours or less. The container is preferably made of a material and shape that can withstand naturally generated pressure and temperature, but from the viewpoint of container durability, it is appropriate to use a corrosion-resistant material such as Teflon (registered trademark) for the inner container. By going through this second step, the aqueous solution of the present invention described above can be obtained.
　次に、第３工程として、第２工程で得られた水溶液内の固形分を分離後、有機溶媒に分散させることもできる。これにより、上記した本発明のコロイド溶液を得ることができる。第２工程で得られた水溶液内の固形分を分離する手法は特に制限しないが、遠心分離法後にろ過する方法、通常の室温から１００℃程度で乾燥する操作、凍結して真空条件に置く操作、他の媒体と置換する操作等を行い固形物とすることができる。このときにいかなる態様でも見かけ上固形物となっていれば、個々のナノ粒子の独立した結晶の状態は保持される。 Next, as the third step, the solid content in the aqueous solution obtained in the second step can be separated and then dispersed in an organic solvent. Thereby, the above-mentioned colloidal solution of the present invention can be obtained. The method for separating the solid content in the aqueous solution obtained in the second step is not particularly limited, but the method for filtering after the centrifugation method, the operation for drying at about 100 ° C. from normal room temperature, and the operation for freezing and placing in vacuum conditions. , It can be made into a solid by performing an operation of replacing it with another medium. At this time, if the nanoparticles are apparently solid in any aspect, the independent crystalline state of the individual nanoparticles is maintained.
　次に、該固形物を有機溶媒に分散させる。有機溶媒は、非極性溶媒が好ましく、トルエン、ベンゼン、石油エーテル、シクロヘキサン、ヘプタン、ドデカン、シクロヘキセン、メシチレン（1,3,5-トリメチルベンゼン）、エチルベンゼン、ジュレン（1,2,4,5-テトラメチルベンゼン）等が挙げられる。また、テトラクロロメタン、クロロホルム、クロロベンゼン、ジクロロベンゼン等も使用することができる。 Next, the solid matter is dispersed in an organic solvent. The organic solvent is preferably a non-polar solvent, preferably toluene, benzene, petroleum ether, cyclohexane, heptane, dodecane, cyclohexene, mesitylene (1,3,5-trimethylbenzene), ethylbenzene, and jurene (1,2,4,5-tetra). Methylbenzene) and the like. Further, tetrachloromethane, chloroform, chlorobenzene, dichlorobenzene and the like can also be used.
　なお、前記第２工程以後の溶液（第２工程で得られた水溶液又は第３工程で得られたコロイド溶液）の溶媒を除去すれば本発明の正方晶ジルコニア微粒子材料及びそれを用いたガス処理用触媒を製造できる。また、第３工程の後に、溶媒を除去すると、本発明の正方晶ジルコニア微粒子材料の独立した結晶の状態は保持されジルコニア微粒子の製造法としてさらに好ましい。 If the solvent of the solution after the second step (the aqueous solution obtained in the second step or the colloidal solution obtained in the third step) is removed, the square zirconia fine particle material of the present invention and gas treatment using the same are used. Can produce a solvent for use. Further, when the solvent is removed after the third step, the independent crystalline state of the tetragonal zirconia fine particle material of the present invention is maintained, which is more preferable as a method for producing zirconia fine particles.
　５．製造方法
　次に、本発明の単斜晶ジルコニア微粒子材料や本発明の単斜晶ジルコニア微粒子材料を含む水溶液又はコロイド溶液、本発明の単斜晶ジルコニア微粒子材料を含むナノシート材料、並びに本発明の単斜晶ジルコニア微粒子材料の製造方法について説明する。本発明の単斜晶ジルコニア微粒子材料は、上述したように単斜晶ジルコニア粒子であり、本発明の製造方法によれば、それらが有機物等と複合化され微粒子が分散しているコロイド溶液として得ることもできる。 5. Production Method Next, an aqueous solution or colloidal solution containing the monoclinic zirconia fine particle material of the present invention or the monoclinic zirconia fine particle material of the present invention, a nanosheet material containing the monoclinic zirconia fine particle material of the present invention, and a single of the present invention. A method for producing a monoclinic zirconia fine particle material will be described. The monoclinic zirconia fine particle material of the present invention is monoclinic zirconia particles as described above, and according to the production method of the present invention, they are combined with an organic substance or the like to obtain a colloidal solution in which the fine particles are dispersed. You can also do it.
　このような本発明の製造方法は、水溶性ジルコニウム塩及び水溶性界面活性剤を含む水溶液をアルカリ性として沈殿物含有水溶液を得る第１工程と、前記沈殿物含有水溶液を１８０℃～６００℃で１２時間以上加熱する第２工程と、を備える。 Such a production method of the present invention comprises a first step of obtaining a precipitate-containing aqueous solution by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline, and the precipitate-containing aqueous solution at 180 ° C. to 600 ° C. 12 A second step of heating for an hour or longer is provided.
　水溶性ジルコニウム塩及び水溶性界面活性剤を含む水溶液をアルカリ性として沈殿物含有水溶液を得る第１工程において、その原料となるジルコニウム塩水溶液の作製方法そのものについては特に制限されることなく公知の方法を用いることができる。本発明で推奨する方法を述べれば、水溶性ジルコニウム塩と水溶性界面活性剤との混合水溶液を塩基で中和すると、ジルコニアが沈殿して水中でゲル状とすることができる。 In the first step of obtaining a precipitate-containing aqueous solution by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline, a known method is used without particular limitation on the method itself for producing the zirconium salt aqueous solution as a raw material. Can be used. Described in the method recommended in the present invention, when a mixed aqueous solution of a water-soluble zirconium salt and a water-soluble surfactant is neutralized with a base, zirconia can be precipitated to form a gel in water.
　水溶性ジルコニウム塩としては、例えば、硝酸ジルコニウム、塩化ジルコニウム、硝酸酸化ジルコニウム、酸化ジルコニウム塩化物等を例示することができる。更に本発明でアルカリ性とするために用い得る塩基としては、例えば、アンモニア、尿素、水酸化ナトリウム、水酸化カリウム等を例示することができる。この共沈法によるジルコニアゲルの作製方法は知られており、中和して沈殿が生成するときにジルコニウムが共存していれば塩基にジルコニウム塩水溶液を加えても、またジルコニウム塩水溶液に塩基を加えてもよい。また、中和時の温度や中和時の混合時間、添加速度を変更することでその性状を変化させることもできるが、いずれの場合でも本発明に使用できる。例えば、添加する塩基の量は水溶性ジルコニム１モルに対して１～１００モルとすることができ、中和時の温度は０～９９℃とすることができ、中和時の混合時間は１分～１００時間とすることができ、添加速度は０．００１～１００ｍＬ／秒とすることができる。 Examples of the water-soluble zirconium salt include zirconium nitrate, zirconium chloride, zirconium nitrate oxide, zirconium chloride chloride and the like. Further, examples of the base that can be used to make the base alkaline in the present invention include ammonia, urea, sodium hydroxide, potassium hydroxide and the like. A method for producing a zirconia gel by this coprecipitation method is known. May be added. Further, the properties can be changed by changing the temperature at the time of neutralization, the mixing time at the time of neutralization, and the addition rate, and in any case, it can be used in the present invention. For example, the amount of base to be added can be 1 to 100 mol per 1 mol of water-soluble zirconim, the temperature at the time of neutralization can be 0 to 99 ° C., and the mixing time at the time of neutralization is 1. It can be from 1 minute to 100 hours, and the addition rate can be 0.001 to 100 mL / sec.
　前記ジルコニウム塩を含む水溶液と塩基とを混合する前に、前記ジルコニウム塩と水溶性有機剤とを混合することが好ましく、水溶性有機剤としていわゆる界面活性剤を利用することが好ましい。界面活性剤としては、例えば、オレイン酸、リノール酸、ルウリン酸等の不飽和脂肪酸及びその塩（ナトリウム塩、カリウム塩等のアルカリ金属塩）；その他のカルボン酸として、飽和脂肪酸、メチルタウリン酸、スルホコハク酸及びその塩（ナトリウム塩、カリウム塩等のアルカリ金属塩）；アルキルベンゼンスルホン酸及びその塩（ナトリウム塩、カリウム塩等のアルカリ金属塩）；αオレフィンスルホン酸（テトラデセンスルホン酸等）及びその塩（ナトリウム塩、カリウム塩等のアルカリ金属塩）；アルキル硫酸エステル酸、アルキルエーテル硫酸エステル塩、フェニルエーテル硫酸エステル塩、エーテル硫酸塩、アルキル硫酸塩、エーテルスルホン酸塩等が挙げられ、分子内に親水性と疎水性の官能基をもつ有機剤であれば広く利用できる。これらは、沈殿する無機成分に吸着している状態を具現すればよいため、ミセルを形成する必要はなく、臨界ミセル濃度など、有機剤の添加濃度の制限がない。単斜晶ジルコニア微粒子材料、水溶液、コロイド溶液及びナノシート材料の製造に使用するジルコニウムの含量を原子数であらわすとき添加する有機分子数との比が０．００１から１０００の広い範囲が適用可能である。 Before mixing the aqueous solution containing the zirconium salt with the base, it is preferable to mix the zirconium salt with the water-soluble organic agent, and it is preferable to use a so-called surfactant as the water-soluble organic agent. Examples of the surfactant include unsaturated fatty acids such as oleic acid, linoleic acid and ruuric acid and salts thereof (alkali metal salts such as sodium salt and potassium salt); and other carboxylic acids include saturated fatty acids and methyl tauric acid. Sulfosuccinic acid and its salts (alkali metal salts such as sodium salt and potassium salt); alkylbenzene sulfonic acid and its salts (alkali metal salts such as sodium salt and potassium salt); α-olefin sulfonic acid (tetradecene sulfonic acid and the like) and their salts. Salts (alkali metal salts such as sodium salt and potassium salt); alkyl sulfate ester acid, alkyl ether sulfate ester salt, phenyl ether sulfate ester salt, ether sulfate salt, alkyl sulfate salt, ether sulfonate and the like can be mentioned in the molecule. Any organic agent having hydrophilic and hydrophobic functional groups can be widely used. Since these may be realized in a state of being adsorbed on the precipitated inorganic component, it is not necessary to form micelles, and there is no limitation on the concentration of the organic agent added such as the critical micelle concentration. A wide range of 0.001 to 1000 is applicable in which the ratio of the content of zirconium used in the production of monoclinic zirconia fine particle materials, aqueous solutions, colloidal solutions and nanosheet materials to the number of organic molecules added when expressed in atomic numbers is 0.001 to 1000. ..
　第２工程では、第１工程を経た沈殿物を含む水溶液を水熱条件に置くことに特徴を有するが１８０℃～６００℃の条件、特に２００℃～５００℃が好ましい。保持時間は１２時間以上であればよく、好ましくは１８時間以上、より好ましくは２４時間以上であることである。保持時間については、経済的に許す範囲で長時間の保持が好ましく、上限値は特に制限はないが、通常１０００時間以下が好ましい。容器は自然的に発生する圧力と温度に耐える状態の材質と形状が好ましいが、容器の耐久性の観点からテフロン（登録商標）等の耐腐食性材を内容器に用いることが適当である。この第２工程を経ることで、上記した本発明の水溶液を得ることができる。 The second step is characterized in that the aqueous solution containing the precipitate that has undergone the first step is placed under hydrothermal conditions, but the conditions of 180 ° C to 600 ° C, particularly 200 ° C to 500 ° C are preferable. The holding time may be 12 hours or more, preferably 18 hours or more, and more preferably 24 hours or more. The holding time is preferably held for a long time within an economically permissible range, and the upper limit is not particularly limited, but is usually preferably 1000 hours or less. The container is preferably made of a material and shape that can withstand naturally generated pressure and temperature, but from the viewpoint of container durability, it is appropriate to use a corrosion-resistant material such as Teflon (registered trademark) for the inner container. By going through this second step, the aqueous solution of the present invention described above can be obtained.
　次に、第３工程として、第２工程で得られた水溶液内の固形分を分離後、有機溶媒に分散させることもできる。これにより、上記した本発明のコロイド溶液を得ることができる。第２工程で得られた水溶液内の固形分を分離する手法は特に制限しないが、遠心分離法後にろ過する方法、通常の室温から１００℃程度で乾燥する操作、あるいは凍結して真空条件に置く操作、他の媒体と置換する操作等を行い固形物とすることができる。このときにいかなる態様でも見かけ上固形物となっていれば、個々のナノ粒子の独立した結晶の状態は保持される。 Next, as the third step, the solid content in the aqueous solution obtained in the second step can be separated and then dispersed in an organic solvent. Thereby, the above-mentioned colloidal solution of the present invention can be obtained. The method for separating the solid content in the aqueous solution obtained in the second step is not particularly limited, but the method of filtering after the centrifugation method, the operation of drying at about 100 ° C. from normal room temperature, or freezing and placing in vacuum conditions. It can be made into a solid by performing an operation, an operation of replacing it with another medium, or the like. At this time, if the nanoparticles are apparently solid in any aspect, the independent crystalline state of the individual nanoparticles is maintained.
　次に、該固形物を有機溶媒に分散させる。有機溶媒は、非極性溶媒が好ましく、トルエン、ベンゼン、石油エーテル、シクロヘキサン、ヘプタン、ドデカン、シクロヘキセン、メシチレン（1,3,5-トリメチルベンゼン）、エチルベンゼン、ジュレン（1,2,4,5-テトラメチルベンゼン）等が挙げられる。また、テトラクロロメタン、クロロホルム、クロロベンゼン、ジクロロベンゼン等も使用することができる。 Next, the solid matter is dispersed in an organic solvent. The organic solvent is preferably a non-polar solvent, preferably toluene, benzene, petroleum ether, cyclohexane, heptane, dodecane, cyclohexene, mesitylene (1,3,5-trimethylbenzene), ethylbenzene, and jurene (1,2,4,5-tetra). Methylbenzene) and the like. Further, tetrachloromethane, chloroform, chlorobenzene, dichlorobenzene and the like can also be used.
　なお、前記第２工程以後の溶液（第２工程で得られた水溶液又は第３工程で得られたコロイド溶液）の溶媒を除去すればジルコニア微粒子を製造できる。また、第３工程の後に、溶媒を除去すると、本発明の単斜晶ジルコニア微粒子材料の独立した結晶の状態は保持されジルコニア微粒子の製造法としてさらに好ましい。さらに、前記第２工程以後の溶液（第２工程で得られた水溶液又は第３工程で得られたコロイド溶液）を基板上に添加もしくは溶液内に基板を浸漬し取り出すことによってジルコニアナノシート材料とすることもできる。 The zirconia fine particles can be produced by removing the solvent of the solution after the second step (the aqueous solution obtained in the second step or the colloidal solution obtained in the third step). Further, when the solvent is removed after the third step, the independent crystalline state of the monoclinic zirconia fine particle material of the present invention is maintained, which is more preferable as a method for producing zirconia fine particles. Further, the solution after the second step (the aqueous solution obtained in the second step or the colloidal solution obtained in the third step) is added to the substrate or the substrate is immersed in the solution and taken out to obtain a zirconia nanosheet material. You can also do it.
　以下、この発明を更に説明するために実施例を示すが、この発明は実施例に限定されるものではない。 Hereinafter, examples will be shown for further explaining the present invention, but the present invention is not limited to the examples.
　（実施例１）
　試薬特級の硝酸酸化ジルコニウム（富士フイルム和光純薬（株））及びオレイン酸カリウム（富士フイルム和光純薬（株））を所定量秤量して、それぞれ30mLの蒸留水に溶解しジルコニウム塩7mmol/L水溶液及び7mmol/Lオレイン酸塩水溶液を調製した。室温でジルコニウム塩水溶液中にオレイン酸塩水溶液を強く攪拌しながら加え、さらに25質量%のアンモニア水を10mL添加して中和することで沈殿を生成させた。次に、この混合溶液を入れたテフロン（登録商標）容器をステンレス製の加圧容器内に入れ、500rpmで攪拌しながら１００℃で２４時間の水熱処理を行った。その後、室温まで自然冷却し、試料を回収し、反応後の溶液を3000rpmで30分間で遠心分離し、内容物を試料管の下部に濃縮させて上澄みを蒸留水で洗浄する操作を行った後、沈殿物を90℃で24時間、大気中で乾燥後、トルエン中に分散させた。これをSi無反射試料台に滴下して粒子を固定させ、波長0.15418nmのCu-Kα線を出力40mA、40kVで用いて、Ｘ線回折（XRD; MiniFlex II, （株）リガク）分析を行った。粒子形態観察には透過型電子顕微鏡（TEM; JEM2100, 日本電子（株））を200kVで用いた。粒子を含むトルエン溶液を室温でカーボン支持膜上に滴下乾燥して作製した。このとき、また、マルバーン製ゼータサイザーナノSにて溶液内分散粒子の粒径を測定した。 (Example 1)
Reagent special grade zirconium nitrate (Fujifilm Wako Pure Chemical Industries, Ltd.) and potassium oleate (Fujifilm Wako Pure Chemical Industries, Ltd.) are weighed in predetermined amounts, dissolved in 30 mL of distilled water, and zirconium salt 7 mmol / L. An aqueous solution and a 7 mmol / L oleate aqueous solution were prepared. An aqueous solution of oleate was added to the aqueous solution of zirconium salt at room temperature with strong stirring, and 10 mL of 25% by mass aqueous ammonia was added to neutralize the mixture to form a precipitate. Next, a Teflon (registered trademark) container containing this mixed solution was placed in a stainless steel pressurized container, and hydrothermal treatment was performed at 100 ° C. for 24 hours while stirring at 500 rpm. After that, the sample is naturally cooled to room temperature, the sample is collected, the solution after the reaction is centrifuged at 3000 rpm for 30 minutes, the contents are concentrated in the lower part of the sample tube, and the supernatant is washed with distilled water. The precipitate was dried in the air at 90 ° C. for 24 hours and then dispersed in toluene. This is dropped on a Si non-reflective sample table to fix particles, and X-ray diffraction (XRD; MiniFlex II, Rigaku Co., Ltd.) analysis is performed using Cu-Kα rays with a wavelength of 0.15418 nm at an output of 40 mA and 40 kV. It was. A transmission electron microscope (TEM; JEM2100, JEOL Ltd.) was used at 200 kV for particle morphology observation. A toluene solution containing particles was dropped and dried on a carbon support membrane at room temperature to prepare a mixture. At this time, the particle size of the dispersed particles in the solution was also measured with Zetasizer Nano S manufactured by Malvern.
　図１に、本実施例１で作製した粒子の固体状態における透過型電子顕微鏡像を示す。この観察において、それぞれの粒子が独立して、互いに連結することがないことがわかる。それぞれの組成について５観察視野の計１００個の粒子観察において計数したところ、連結した粒子群の数は２個以内であった。また、連結していてもその中の粒子数は２以内であり、その粒径は５ナノメートルを超えることがなかった。すなわち、９５％以上の粒子は独立した状態で存在しており、単結晶の存在割合が９５％以上であることが理解できる。また、高分解能の観察によって格子像が見られ、粒子全体にわたって区切られることなく格子像が観測され粒子全体が１つの結晶であることがわかった。 FIG. 1 shows a transmission electron microscope image of the particles produced in Example 1 in a solid state. In this observation, it can be seen that the particles do not independently connect to each other. When counting each composition in a total of 100 particle observations in 5 observation fields, the number of connected particle groups was 2 or less. Further, even if they were connected, the number of particles in the particles was within 2, and the particle size did not exceed 5 nanometers. That is, it can be understood that 95% or more of the particles exist in an independent state, and the abundance ratio of the single crystal is 95% or more. In addition, a lattice image was seen by high-resolution observation, and the lattice image was observed without being divided over the entire particle, and it was found that the entire particle was one crystal.
　図２に、図１の視野から求めた粒径の分布図を示す。平均粒子径は、２ｎｍで、９５％以上の粒子が５ｎｍ以下にあった。 FIG. 2 shows a distribution map of the particle size obtained from the field of view of FIG. The average particle size was 2 nm, and 95% or more of the particles were 5 nm or less.
　（実施例２～４）
　水熱処理温度を１２０℃（実施例２）、１４０℃（実施例３）、１６０℃（実施例４）とするほか、実施例１と同様の操作で実施例２～４の試料を作製した。 (Examples 2 to 4)
In addition to setting the hydrothermal treatment temperature to 120 ° C. (Example 2), 140 ° C. (Example 3), and 160 ° C. (Example 4), samples of Examples 2 to 4 were prepared by the same operation as in Example 1.
　図３に、本実施例４の１６０℃で作製した粒子の固体状態における透過型電子顕微鏡像を示す。この観察において、それぞれの粒子が独立して、互いに連結することがないことがわかる。それぞれの組成について、５観察視野の計１００個の粒子観察において計数したところ、連結した粒子群の数は５個以内であった。また、連結していてもその粒子数は２個以内であり、その粒径は１０ナノメートルを超えることがなかった。すなわち、９５％以上の粒子は独立した状態で存在ししており、単結晶の存在割合が９５％以上であることが理解できる。また、高分解能の観察によって格子像が見られ、粒子全体にわたって区切られることなく格子像が観測され粒子全体が１つの結晶であることがわかった。 FIG. 3 shows a transmission electron microscope image of the particles produced at 160 ° C. in Example 4 in a solid state. In this observation, it can be seen that the particles do not independently connect to each other. When each composition was counted in a total of 100 particle observations in 5 observation fields, the number of connected particle groups was 5 or less. Further, even if they were connected, the number of particles was 2 or less, and the particle size did not exceed 10 nanometers. That is, it can be understood that 95% or more of the particles exist in an independent state, and the abundance ratio of the single crystal is 95% or more. In addition, a lattice image was seen by high-resolution observation, and the lattice image was observed without being divided over the entire particle, and it was found that the entire particle was one crystal.
　図４に、図３の視野から求めた粒子径の分布図を示す。平均粒径は、２ｎｍで、９５％以上の粒子が５ｎｍ以下にあった。 FIG. 4 shows a distribution map of the particle size obtained from the field of view of FIG. The average particle size was 2 nm, and 95% or more of the particles were 5 nm or less.
　図５に、実施例１～４において１００℃、１２０℃、１４０℃、１６０℃で作製した粒子の粉末Ｘ線回折図形を後述する比較例１の試料（２００℃）とともに示す。実施例１～４の１００℃～１６０℃の条件ではいずれも正方晶ZrO2の回折図形を示し、単斜晶がこれらの試料には見られなかった。なお、Ｘ線回折図形は、実施例１～４の水熱処理後に水溶液を乾燥した状態の試料で測定しても同様であった。 FIG. 5 shows the powder X-ray diffraction pattern of the particles prepared at 100 ° C., 120 ° C., 140 ° C., and 160 ° C. in Examples 1 to 4 together with the sample (200 ° C.) of Comparative Example 1 described later. All of Examples 1 to 4 showed a diffraction pattern of tetragonal ZrO 2 under the conditions of 100 ° C. to 160 ° C., and no monoclinic crystal was observed in these samples. The X-ray diffraction pattern was the same even when the aqueous solution was measured in a dried sample after the hydrothermal treatment of Examples 1 to 4.
　結晶測定としてしばしば利用されるシェラーの式で見積もった結晶子径は組成により実施例１～４のいずれも約２ｎｍであり極微小結晶は測定できないことから数値は信頼できるとは限らないが微小結晶の存在を示した。 The crystallite diameter estimated by Scheller's formula, which is often used for crystal measurement, is about 2 nm in each of Examples 1 to 4 depending on the composition, and very small crystals cannot be measured. Therefore, the numerical values are not always reliable, but fine crystals. Showed the existence of.
　実施例１でのトルエン溶液についてマルバーン製ゼータサイザーナノSにて液中における平均粒子径を測定したところ３ｎｍの平均粒子径であることを示した。すなわち、上記でのナノ結晶は個々に分散して溶液中にあり、ジルコニア単結晶が２０ｎｍ以下の粒径で分散したコロイド溶液となっていることが理解できる。このコロイド溶液は2か月を経てもその特性に変化はなかった。 The average particle size of the toluene solution in Example 1 was measured with the Zetasizer Nano S manufactured by Malvern in the solution, and it was shown that the average particle size was 3 nm. That is, it can be understood that the nanocrystals described above are individually dispersed in the solution, and the zirconia single crystal is a colloidal solution dispersed in a particle size of 20 nm or less. The properties of this colloidal solution did not change after 2 months.
　（実施例５～７）
　界面活性剤をオレイン酸カリウムではなく、リノール酸（実施例５）、メチルタウリン酸（実施例６）又はテトラデセンスルホン酸ナトリウム（αオレフィンスルホン酸）（実施例７）とするほか、１２０℃で実施例２と同様の操作で試料を作製した。いずれの作製試料の粉末Ｘ線回折図形からも、正方晶ZrO2のみの回折図形がみられた。なお、Ｘ線回折図形で水熱処理後に水溶液を乾燥した状態の試料を再度600℃加熱後で測定しても正方晶ZrO2のみであった。 (Examples 5 to 7)
The surfactant is not potassium oleate but linoleic acid (Example 5), methyl tauric acid (Example 6) or sodium tetradecene sulfonate (α-olefin sulfonic acid) (Example 7), and at 120 ° C. A sample was prepared by the same operation as in Example 2. From the powder X-ray diffraction pattern of each of the prepared samples, a diffraction pattern of only tetragonal ZrO 2 was observed. In addition, even when the sample in the state where the aqueous solution was dried after the hydrothermal treatment by the X-ray diffraction pattern was measured again after heating at 600 ° C., only tetragonal ZrO 2 was found.
　（実施例８～１１）
　水熱処理温度を２４時間ではなく、１２時間とするほか、１００℃（実施例８）、１２０℃（実施例９）、１４０℃（実施例１０）又は１６０℃（実施例１１）で、実施例１～４と同様の操作で試料を作製した。粉末Ｘ線回折図形からいずれの作製試料も正方晶ZrO2のみの回折図形を示し、単斜晶の生成は見られなかった。なお、Ｘ線回折図形で水熱処理後に水溶液を乾燥した状態の試料を再度600℃で加熱して試料を測定しても正方晶ZrO2のみであった。 (Examples 8 to 11)
In addition to setting the hydrothermal treatment temperature to 12 hours instead of 24 hours, Examples are performed at 100 ° C. (Example 8), 120 ° C. (Example 9), 140 ° C. (Example 10) or 160 ° C. (Example 11). Samples were prepared in the same manner as in steps 1 to 4. From the powder X-ray diffraction pattern, all the prepared samples showed a diffraction pattern of only tetragonal ZrO 2 , and no formation of monoclinic crystals was observed. It should be noted that even when the sample in which the aqueous solution was dried after hydrothermal treatment using an X-ray diffraction pattern was heated again at 600 ° C. and the sample was measured, only tetragonal ZrO 2 was found.
　（比較例１）
　水熱処理温度を２００℃とするほか、実施例１と同様の操作で比較例１の試料を作製した。図５にこの試料の粉末Ｘ線回折図形を実施例１～４とともに示す。単斜晶ZrO2の回折図形を示し、正方晶ZrO2の回折図形は見られなかったことから、この条件で作製したジルコニアでは正方晶として得られなかった。 (Comparative Example 1)
In addition to setting the hydrothermal treatment temperature to 200 ° C., a sample of Comparative Example 1 was prepared by the same operation as in Example 1. FIG. 5 shows a powder X-ray diffraction pattern of this sample together with Examples 1 to 4. Since the diffraction pattern of the monoclinic ZrO 2 was shown and the diffraction pattern of the tetragonal ZrO 2 was not seen, the zirconia produced under these conditions could not be obtained as a tetragonal crystal.
　また、図６に実施例１～４及び比較例１のジルコニア微粒子材料を大気中６００℃、3時間加熱したのちの粉末Ｘ線回折図形を示す。これらの図形は結晶相が熱処理前後で変わらないことを示しており、正方晶ジルコニアが加熱処理後そのまま利用できることを示している。 Further, FIG. 6 shows a powder X-ray diffraction pattern of the zirconia fine particle materials of Examples 1 to 4 and Comparative Example 1 after being heated in the air at 600 ° C. for 3 hours. These figures show that the crystal phase does not change before and after the heat treatment, and that the tetragonal zirconia can be used as it is after the heat treatment.
　（試験例１：触媒試験１）
　本発明の正方晶ジルコニア微粒子材料の触媒特性を評価するため、実施例２（１２０℃）及び比較例１（２００℃）と同じ操作で作製した微粒子を１００℃大気中で一夜乾燥後４００℃大気中で３時間熱処理したのち、それぞれ硝酸ロジウム水溶液（田中貴金属工業（株）製）を用いてロジウム０．４重量％を含浸担持し、６００℃大気中で３時間で熱処理して、ロジウム担持触媒A（実施例２から）及びB（比較例１から）を作製した。試料の排ガス浄化性能を評価するため、固定床流通触媒試験装置により排気モデルガスを流通させ触媒浄化性能を評価した。測定操作は、試料０．１グラムを秤量しペレット状にした後に粗破砕し石英試験管に入れ、排ガスを模擬したガス組成の混合ガスを５００ml/minで流し、昇温速度１０℃/minで６００℃まで昇温し、６００℃で1時間保持を行った後、冷却し、再び同条件で昇温し、その昇温時のガス組成を測定して、一酸化炭素（CO）、炭化水素（HC）、窒素酸化物（NO）の浄化特性（ライトオフ特性）を評価した。使用した混合ガス組成（体積%）は、C3H6 0.04%、NO 0.1%、CO 0.3%、O2 0.33%、H2 0.1%、H2O 2%でその他はN2とした。 (Test Example 1: Catalyst test 1)
In order to evaluate the catalytic properties of the rectangular zirconia fine particle material of the present invention, the fine particles prepared by the same operation as in Example 2 (120 ° C.) and Comparative Example 1 (200 ° C.) were dried in the air at 100 ° C. overnight and then at 400 ° C. After heat-treating in 3 hours, each is impregnated with 0.4% by weight of rhodium using an aqueous solution of rhodium nitrate (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.), and heat-treated in the air at 600 ° C. for 3 hours to carry a rhodium-supporting catalyst. A (from Example 2) and B (from Comparative Example 1) were prepared. In order to evaluate the exhaust gas purification performance of the sample, the exhaust model gas was circulated by a fixed bed flow catalyst test device to evaluate the catalyst purification performance. The measurement operation is as follows: 0.1 g of sample is weighed into pellets, coarsely crushed and placed in a quartz test tube, a mixed gas having a gas composition simulating exhaust gas is flowed at 500 ml / min, and the temperature rise rate is 10 ° C./min. The temperature is raised to 600 ° C., held at 600 ° C. for 1 hour, then cooled, the temperature is raised again under the same conditions, the gas composition at the time of the temperature rise is measured, and carbon monoxide (CO) and hydrocarbons are measured. The purification characteristics (light-off characteristics) of (HC) and nitrogen oxides (NO) were evaluated. The mixed gas composition (volume%) used was C 3 H 6 0.04%, NO 0.1%, CO 0.3%, O 2 0.33%, H 2 0.1%, H 2 O 2%, and the others were N 2 .
　（試験例２：触媒試験２）
　触媒の作製時の最終の熱処理温度を６００℃ではなく８００℃とするほか、試験例１と同様の操作により、ロジウム担持触媒C（実施例２から）及びD（比較例１から）を作製し、評価試験を行った。 (Test Example 2: Catalyst test 2)
The final heat treatment temperature at the time of producing the catalyst was set to 800 ° C. instead of 600 ° C., and rhodium-supported catalysts C (from Example 2) and D (from Comparative Example 1) were produced by the same operation as in Test Example 1. , An evaluation test was conducted.
　表１に、一酸化炭素（CO）、炭化水素（HC）、窒素酸化物（NO）の浄化率が８０％となる温度をまとめて比較した。温度が低いほど低温で浄化できる、すなわち触媒が高い活性をもつことを示している。AとBを比較すると、正方晶ジルコニアを担体として用いた触媒のほうが高活性であった。また、同様に、CとDを比較すると、正方晶ジルコニアを担体として用いた触媒のほうが高活性であった。このときのCとDの触媒の比表面積に差はなく、また、Cの比表面積はDに比べて低く、これらの活性の違いは異なる結晶相のジルコニア上でのロジウムの状態によるものであると推察される。 Table 1 summarizes the temperatures at which the purification rates of carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NO) are 80%. The lower the temperature, the lower the temperature that can be purified, that is, the higher the activity of the catalyst. Comparing A and B, the catalyst using tetragonal zirconia as a carrier was more active. Similarly, when C and D were compared, the catalyst using tetragonal zirconia as a carrier had higher activity. At this time, there is no difference in the specific surface area of the catalysts of C and D, and the specific surface area of C is lower than that of D, and the difference in their activities is due to the state of rhodium on zirconia of different crystal phases. It is inferred that.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　これらの触媒試料の粉末Ｘ線回折図形を調べたところ、AとCでは正方晶、BとDでは単斜晶であり、ジルコニア各相が安定に存在する触媒であった。このような活性な金属を担持する性能は結晶構造からくる表面構造と相互作用に依存するので、他の貴金属ならびに活性金属でも同様な正方晶相の効果が期待できる。 Examination of the powder X-ray diffraction pattern of these catalyst samples revealed that A and C were tetragonal crystals, and B and D were monoclinic crystals, and each phase of zirconia was stably present. Since the ability to support such an active metal depends on the surface structure and interaction of the crystal structure, the same tetragonal phase effect can be expected for other noble metals and active metals.
　（実施例１２～１３）
　試薬特級の硝酸酸化ジルコニウム（富士フイルム和光純薬（株））及びオレイン酸カリウム（富士フイルム和光純薬（株））を所定量秤量して、それぞれ30mLの蒸留水に溶解しジルコニウム塩7mmol/L水溶液及び7mmol/Lオレイン酸塩水溶液を調製した。室温でジルコニウム塩水溶液中にオレイン酸塩水溶液を強く攪拌しながら加え、さらに25質量%のアンモニア水を10mL添加して中和することで沈殿を生成させた。次に、この混合溶液を入れたテフロン（登録商標）容器をステンレス製の加圧容器内に入れ、500rpmで攪拌しながら２００℃で１２時間（実施例１２）又は４８時間（実施例１３）の水熱処理を行った。その後、室温まで自然冷却し、試料を回収し、反応後の溶液を3000rpmで30分間で遠心分離し、内容物を試料管の下部に濃縮させて上澄みを蒸留水で洗浄する操作を行った後、沈殿物を90℃で24時間、大気中で乾燥後、トルエン中に分散させた。 (Examples 12 to 13)
Reagent special grade zirconium nitrate (Fujifilm Wako Pure Chemical Industries, Ltd.) and potassium oleate (Fujifilm Wako Pure Chemical Industries, Ltd.) are weighed in predetermined amounts, dissolved in 30 mL of distilled water, and zirconium salt 7 mmol / L. An aqueous solution and a 7 mmol / L oleate aqueous solution were prepared. An aqueous solution of oleate was added to the aqueous solution of zirconium salt at room temperature with strong stirring, and 10 mL of 25% by mass aqueous ammonia was added to neutralize the mixture to form a precipitate. Next, a Teflon (registered trademark) container containing this mixed solution is placed in a stainless steel pressurized container, and the mixture is stirred at 500 rpm for 12 hours (Example 12) or 48 hours (Example 13) at 200 ° C. Hydrothermal treatment was performed. After that, the sample is naturally cooled to room temperature, the sample is collected, the solution after the reaction is centrifuged at 3000 rpm for 30 minutes, the contents are concentrated in the lower part of the sample tube, and the supernatant is washed with distilled water. The precipitate was dried in the air at 90 ° C. for 24 hours and then dispersed in toluene.
　これをSi無反射試料台に滴下して粒子を固定させ、波長0.15418nmのCu-Kα線を出力40mA、40kVで用いて、Ｘ線回折（XRD; MiniFlex II, （株）リガク）分析を行った。粒子形態観察には透過型電子顕微鏡（TEM; JEM2100, 日本電子（株））を200kVで用いた。粒子を含むトルエン溶液を室温でカーボン支持膜上に滴下乾燥して作製した。このとき、また、マルバーン製ゼータサイザーナノSにて溶液内分散粒子の粒径を測定した。 This is dropped on a Si non-reflective sample table to fix particles, and X-ray diffraction (XRD; MiniFlex II, Rigaku Co., Ltd.) analysis is performed using Cu-Kα rays with a wavelength of 0.15418 nm at an output of 40 mA and 40 kV. It was. A transmission electron microscope (TEM; JEM2100, JEOL Ltd.) was used at 200 kV for particle morphology observation. A toluene solution containing particles was dropped and dried on a carbon support membrane at room temperature to prepare a mixture. At this time, the particle size of the dispersed particles in the solution was also measured with Zetasizer Nano S manufactured by Malvern.
　図７に、実施例１２（１２時間）及び１３（４８時間）において２００℃で作製した粒子の粉末Ｘ線回折図形を示す。いずれも単斜晶ZrO2の回折図形を示した。なお、Ｘ線回折図形は、水熱処理後に水溶液を乾燥した状態の試料で測定しても同様であった。 FIG. 7 shows a powder X-ray diffraction pattern of particles prepared at 200 ° C. in Examples 12 (12 hours) and 13 (48 hours). Both showed a diffraction pattern of monoclinic ZrO 2 . The X-ray diffraction pattern was the same even when the aqueous solution was measured with a sample in a dried state after the hydrothermal treatment.
　図８に、本実施例１３（４８時間）で作製した粒子の固体状態における透過型電子顕微鏡像を示す。この観察において、全ての粒子が、一般的な形状を示さず、分岐があることに特徴を有する材料であった。計５０個の粒子観察において観察したところ、不規則な方向に複数の突起が伸びる形状を有する粒子の数が全体の８５％を占めており、分岐が３つ以上ある粒子の数が全体の６０％を占めていた。その粒径は５ナノメートル以下の粒子も存在していた。また、高分解能の観察によって格子像が見られ、粒子全体にわたって区切られることなく格子像が観測され粒子全体が１つの結晶である場合や、分岐した領域ごとに別の結晶である場合もあった。実施例１２（１２時間）の試料についても同様に測定したところ、全ての粒子が、一般的な形状を示さず、分岐があることに特徴を有する材料であり、不規則な方向に複数の突起が伸びる形状を有する粒子の数が全体の７５％を占めており、分岐が３つ以上ある粒子の数が全体の５５％を占めていた。図８から得られた粒子の平均粒子径を算出したところ、１３．２ｎｍであった。なお、平均粒子径とは、固体状態においては電子顕微鏡像において、ｉｍａｇｅＪを用いて個々の粒子の円相当径から算出した面積長さ平均径を意味する。 FIG. 8 shows a transmission electron microscope image of the particles produced in Example 13 (48 hours) in a solid state. In this observation, all particles were materials that did not show a general shape and were characterized by branching. When observed in a total of 50 particles, the number of particles having a shape in which a plurality of protrusions extend in irregular directions accounts for 85% of the total, and the number of particles having three or more branches is 60 in the total. Occupied%. Some particles had a particle size of 5 nanometers or less. In addition, a lattice image was seen by high-resolution observation, and the lattice image was observed without being divided over the entire particle, and the entire particle was one crystal, or it was a different crystal for each branched region. .. When the sample of Example 12 (12 hours) was also measured in the same manner, all the particles did not show a general shape and were characterized by having branches, and a plurality of protrusions in irregular directions. The number of particles having an elongated shape accounted for 75% of the total, and the number of particles having three or more branches accounted for 55% of the total. The average particle size of the particles obtained from FIG. 8 was calculated to be 13.2 nm. In the solid state, the mean particle diameter means the area length mean diameter calculated from the circle equivalent diameter of each particle using imageJ in the electron microscope image.
　図９に、図８の視野から求めた粒子径の分布図を示す。この結果、粒径が５～３０ｎｍの粒子の割合が８０％以上であるジルコニア微粒子材料であった。また、トルエン溶液についてマルバーン製ゼータサイザーナノＳにて平均粒子径を測定したところ約１２ｎｍであることを示した。すなわち、上記でのナノ結晶は個々に分散して溶液中にあり、分散したコロイド溶液となっている。この液は２か月を経てもその特性に変化はなかった。実施例１２（１２時間）の試料についても同様に測定したところ、固体状態において、粒径が５～３０ｎｍの粒子の割合は７５％であり、トルエン溶液についてマルバーン製ゼータサイザーナノＳにて平均粒子径を測定したところ約１０ｎｍであった。なお、平均粒子径とは、溶液中のコロイドにあっては動的光散乱法により算出する拡散係数相当径であり、散乱光強度基準により測定される平均粒子径を意味する。 FIG. 9 shows a distribution map of the particle size obtained from the field of view of FIG. As a result, it was a zirconia fine particle material in which the proportion of particles having a particle size of 5 to 30 nm was 80% or more. Further, when the average particle size of the toluene solution was measured with Zetasizer Nano S manufactured by Malvern, it was shown to be about 12 nm. That is, the nanocrystals described above are individually dispersed and present in the solution, forming a dispersed colloidal solution. The characteristics of this solution did not change even after 2 months. When the sample of Example 12 (12 hours) was also measured in the same manner, the proportion of particles having a particle size of 5 to 30 nm was 75% in the solid state, and the average particles of the toluene solution were averaged with Zetasizer Nano S manufactured by Malvern. The diameter was measured and found to be about 10 nm. The average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
　（実施例１４）
　実施例１３で作製したトルエン分散液（水熱条件、２００℃、４８時間で作製）を用いてSi単結晶板上にジルコニアナノ粒子を担持した。１００℃一夜大気中で乾燥後、（株）島津製作所製SPM9700原子間力顕微鏡によって固体状態の表面形態を観察した。同時に、同機により基板から粒子表面までの厚さを計測した。図１０に、本実施例１４の観察像を示す。この観察において、厚みが平均で１±０．３ｎｍであるそれぞれの粒子が観察され、また基板上では部分的に連結して膜状となっていた。特異的に堆積した小さい粒子の場所を除いて、粒子は基板に沿って存在し、その厚みを計測したところ、この視野内ではすべて３ｎｍ以下であった。さらに、A-B間で示される膜形態で、厚み２±０．３ｎｍで３００ｎｍの距離にわたって基板上を覆ったナノシート材料が形成されていた。すなわち、この粒子はシート類似形状を特徴として、全ての粒子の厚みが３ｎｍ以下であるシート状材料である。また、溶液を基板上に添加もしくは溶液内に基板を浸漬し取り出すことによるジルコニアナノシート材料の形成が実現した。実施例１２（１２時間）の試料についても同様に測定したところ、厚みが平均で１±０．３ｎｍである粒子が観察され、また、厚みが２±０．３ｎｍであるナノシート材料が形成されていた。 (Example 14)
Zirconia nanoparticles were supported on a Si single crystal plate using the toluene dispersion prepared in Example 13 (prepared under hydrothermal conditions at 200 ° C. for 48 hours). After drying in the air at 100 ° C. overnight, the surface morphology in the solid state was observed with an SPM9700 atomic force microscope manufactured by Shimadzu Corporation. At the same time, the thickness from the substrate to the particle surface was measured by the same machine. FIG. 10 shows an observation image of the 14th embodiment. In this observation, each particle having an average thickness of 1 ± 0.3 nm was observed, and was partially connected to form a film on the substrate. Except for the location of the specifically deposited small particles, the particles existed along the substrate, and the thickness of the particles was measured and found to be 3 nm or less in this field of view. Further, in the film form shown between AB, a nanosheet material having a thickness of 2 ± 0.3 nm and covering the substrate over a distance of 300 nm was formed. That is, these particles are a sheet-like material characterized by a sheet-like shape and having a thickness of all particles of 3 nm or less. Further, the formation of the zirconia nanosheet material was realized by adding the solution onto the substrate or immersing the substrate in the solution and taking it out. When the sample of Example 12 (12 hours) was also measured in the same manner, particles having an average thickness of 1 ± 0.3 nm were observed, and a nanosheet material having a thickness of 2 ± 0.3 nm was formed. It was.
　（実施例１５～１７）
　界面活性剤をオレイン酸カリウムではなく、リノール酸（実施例１５）、メチルタウリン酸（実施例１６）又はテトラデセンスルホン酸ナトリウム（αオレフィンスルホン酸）（実施例１７）とするほか、２００℃、４８時間で作製条件、実施例１２～１４と同様の操作で試料を作製した。いずれの作製試料の粉末Ｘ線回折図形からも、単斜晶ZrO2の回折図形がみられた。 (Examples 15 to 17)
The surfactant is not potassium oleate but linoleic acid (Example 15), methyl tauric acid (Example 16) or sodium tetradecene sulfonate (α-olefin sulfonic acid) (Example 17), and at 200 ° C. A sample was prepared in 48 hours under the same preparation conditions as in Examples 12 to 14. From the powder X-ray diffraction pattern of each of the prepared samples, a diffraction pattern of monoclinic ZrO 2 was observed.
　実施例１５では、全ての粒子が、一般的な形状を示さず、分岐があることに特徴を有する材料であり、不規則な方向に複数の突起が伸びる形状を有する粒子の数が全体の８０％を占めており、分岐が３つ以上ある粒子の数が全体の５０％を占めており、粒径が５～３０ｎｍの粒子の割合は８０％であり、トルエン溶液についてマルバーン製ゼータサイザーナノＳにて粒径を測定したところ平均粒子径約１２ｎｍであった。また、厚みが平均で１±０．３ｎｍである粒子が観察され、また、厚みが２±０．３ｎｍであるナノシート材料も形成された。なお、平均粒子径とは、溶液中のコロイドにあっては動的光散乱法により算出する拡散係数相当径であり、散乱光強度基準により測定される平均粒子径を意味する。 In Example 15, all the particles are materials that do not show a general shape and are characterized by having branches, and the total number of particles having a shape in which a plurality of protrusions extend in irregular directions is 80 in total. The number of particles with 3 or more branches accounts for 50% of the total, the proportion of particles with a particle size of 5 to 30 nm is 80%, and the Zetasizer Nano S manufactured by Malvern is used for the toluene solution. When the particle size was measured with, the average particle size was about 12 nm. In addition, particles having an average thickness of 1 ± 0.3 nm were observed, and nanosheet materials having a thickness of 2 ± 0.3 nm were also formed. The average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
　実施例１６では、全ての粒子が、一般的な形状を示さず、分岐があることに特徴を有する材料であり、不規則な方向に複数の突起が伸びる形状を有する粒子の数が全体の７５％を占めており、分岐が３つ以上ある粒子の数が全体の４５％を占めており、粒径が５～３０ｎｍの粒子の割合は８０％であり、トルエン溶液についてマルバーン製ゼータサイザーナノＳにて粒径を測定したところ平均粒子径約１４ｎｍであった。また、厚みが平均で１±０．３ｎｍである粒子が観察され、また、厚みが２±０．３ｎｍであるナノシート材料も形成された。なお、平均粒子径とは、溶液中のコロイドにあっては動的光散乱法により算出する拡散係数相当径であり、散乱光強度基準により測定される平均粒子径を意味する。 In Example 16, all the particles are materials that do not show a general shape and are characterized by having branches, and the total number of particles having a shape in which a plurality of protrusions extend in irregular directions is 75 in total. The number of particles with 3 or more branches accounts for 45% of the total, the proportion of particles with a particle size of 5 to 30 nm is 80%, and the Zetasizer Nano S manufactured by Malvern is used for the toluene solution. When the particle size was measured with, the average particle size was about 14 nm. In addition, particles having an average thickness of 1 ± 0.3 nm were observed, and nanosheet materials having a thickness of 2 ± 0.3 nm were also formed. The average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
　実施例１７では、全ての粒子が、一般的な形状を示さず、分岐があることに特徴を有する材料であり、不規則な方向に複数の突起が伸びる形状を有する粒子の数が全体の７０％を占めており、分岐が３つ以上ある粒子の数が全体の４５％を占めており、粒径が５～３０ｎｍの粒子の割合は８０％であり、トルエン溶液についてマルバーン製ゼータサイザーナノＳにて粒径を測定したところ平均粒子径約１４ｎｍであった。また、厚みが平均で１±０．３ｎｍである粒子が観察され、また、厚みが２±０．３ｎｍであるナノシート材料も形成された。なお、平均粒子径とは、溶液中のコロイドにあっては動的光散乱法により算出する拡散係数相当径であり、散乱光強度基準により測定される平均粒子径を意味する。 In Example 17, all the particles do not show a general shape and are characterized by having branches, and the total number of particles having a shape in which a plurality of protrusions extend in irregular directions is 70 in total. The number of particles with 3 or more branches accounts for 45% of the total, the proportion of particles with a particle size of 5 to 30 nm is 80%, and the Zetasizer Nano S manufactured by Malvern is used for the toluene solution. When the particle size was measured with, the average particle size was about 14 nm. In addition, particles having an average thickness of 1 ± 0.3 nm were observed, and nanosheet materials having a thickness of 2 ± 0.3 nm were also formed. The average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
　（実施例１８）
　水熱処理温度を２００℃、７２時間とするほか、実施例１２～１４と同様の操作で試料を作製した。作製試料の粉末Ｘ線回折図形から単斜晶ZrO2であり、さらには分岐の粒子材料が形成された。全ての粒子が、一般的な形状を示さず、分岐があることに特徴を有する材料であり、不規則な方向に複数の突起が伸びる形状を有する粒子の数が全体の７０％を占めており、分岐が３つ以上ある粒子の数が全体の６０％を占めており、粒径が５～３０ｎｍの粒子の割合は８０％であり、トルエン溶液についてマルバーン製ゼータサイザーナノＳにて粒径を測定したところ平均粒子径約１６ｎｍであった。また、厚みが平均で１±０．３ｎｍである粒子が観察され、また、厚みが２±０．３ｎｍであるナノシート材料も形成された。なお、平均粒子径とは、溶液中のコロイドにあっては動的光散乱法により算出する拡散係数相当径であり、散乱光強度基準により測定される平均粒子径を意味する。 (Example 18)
The hydrothermal treatment temperature was set to 200 ° C. for 72 hours, and a sample was prepared by the same operation as in Examples 12 to 14. From the powder X-ray diffraction pattern of the prepared sample, a monoclinic ZrO 2 and a branched particle material were formed. All particles do not show a general shape and are characterized by having branches, and the number of particles having a shape in which multiple protrusions extend in irregular directions accounts for 70% of the total. The number of particles having three or more branches accounts for 60% of the total, and the proportion of particles having a particle size of 5 to 30 nm is 80%. The particle size of the toluene solution is determined by Malvern Zetasizer Nano S. When measured, the average particle size was about 16 nm. In addition, particles having an average thickness of 1 ± 0.3 nm were observed, and nanosheet materials having a thickness of 2 ± 0.3 nm were also formed. The average particle size is a diffusion coefficient equivalent diameter calculated by a dynamic light scattering method for a colloid in a solution, and means an average particle size measured by a scattered light intensity standard.
　（試験例３）
　本発明の単斜晶ジルコニア微粒子材料の触媒担体として特性を評価するため、２００℃で加熱し４８時間保持して作製した実施例１３の微粒子材と、特許文献４を参考にしてオキシ塩化ジルコニウム塩溶液にアンモニア水を加え混合物を加熱乾燥後、固形物を粉砕して大気中５００℃１時間焼成することにより正方晶ジルコニアを作製して比較材（比較例２）とした。これらの試料を６００℃、3時間大気中で焼成して単斜晶（実施例１３）と正方晶（比較例２）の粉末を得た。これらそれぞれ硝酸ロジウム水溶液（田中貴金属製）を用いてロジウム０．４重量％を含浸担持し、再度６００℃大気中で３時間で熱処理して、ロジウム担持触媒A（実施例１３から）及びB（比較例２から）を作製した。He希釈水素５体積％ガスを流通させ４００℃で３０分処理したのち室温まで冷やし、さらにHeに切り替え後COガスをパルス状に導入し触媒上へのCO吸着量を調べ、CO／Rh原子比率（分散度）を計算した。比較例２からの触媒では、分散度が０．２、実施例１３からの試料では０．５５であった。実施例１３の材料は、Rh触媒の分散性向上に優れていた。これは、特異形状の単斜晶ジルコニア粒子であることのよるものと考えられる。金属成分の分散性能は、触媒の活性向上に効果があることが知られ、結晶構造と形状からくる表面構造に依存する相互作用の影響であるので、他の貴金属及び活性金属でも同様な本材の効果が期待できる。 (Test Example 3)
In order to evaluate the characteristics of the monoclinic zirconia fine particle material of the present invention as a catalyst carrier, the fine particle material of Example 13 prepared by heating at 200 ° C. and holding for 48 hours and the zirconium oxychloride salt with reference to Patent Document 4. Tetragonal zirconia was prepared by adding aqueous ammonia to the solution, heating and drying the mixture, crushing the solid, and calcining the mixture in the air at 500 ° C. for 1 hour to prepare a comparative material (Comparative Example 2). These samples were calcined in the air at 600 ° C. for 3 hours to obtain powders of monoclinic crystals (Example 13) and tetragonal crystals (Comparative Example 2). Each of these was impregnated and supported with 0.4% by weight of rhodium using an aqueous solution of rhodium nitrate (manufactured by Tanaka Kikinzoku), and heat-treated again in the air at 600 ° C. for 3 hours to carry rhodium-supporting catalysts A (from Example 13) and B (from Example 13). (From Comparative Example 2) was prepared. He diluted hydrogen 5% by volume gas was circulated and treated at 400 ° C. for 30 minutes, then cooled to room temperature, and after switching to He, CO gas was introduced in a pulse shape to examine the amount of CO adsorbed on the catalyst, and the CO / Rh atomic ratio was examined. (Dispersity) was calculated. The dispersity of the catalyst from Comparative Example 2 was 0.2, and that of the sample from Example 13 was 0.55. The material of Example 13 was excellent in improving the dispersibility of the Rh catalyst. This is considered to be due to the monoclinic zirconia particles having a peculiar shape. The dispersion performance of metal components is known to be effective in improving the activity of catalysts, and is the effect of interactions that depend on the surface structure that comes from the crystal structure and shape. Therefore, the same material can be used with other precious metals and active metals. The effect of can be expected.
　（試験例４）
　本発明の単斜晶ジルコニア微粒子材料の触媒担体として特性を評価するため、実施例１２の微粒子溶液を洗浄、乾燥後に、６００℃、3時間大気中で焼成して粉末を得た。市販の酸化セリウムゾル（日産化学製）を６００℃、3時間大気中で焼成して作製した粉末を比較材（比較例３）とした。これらそれぞれに硝酸パラジウム水溶液（田中貴金属製）を用いてパラジウム１重量％を含浸担持し、再度６００℃大気中で３時間で熱処理して、パラジウム担持触媒E（実施例１２から）及びF（比較例３から）を作製した。試験例１と同様の操作により、一酸化炭素（CO）、炭化水素（HC）、窒素酸化物（NO）の浄化率が８０％となる温度を測定した結果を表２に比較した。温度が低いほど低温で浄化できる、すなわち触媒が高い活性をもつことを示している。CとDを比較すると、本発明のジルコニアを担体として用いた触媒のほうが、一般的に高活性とされる酸化セリウムゾル材を用いたよりも、NOとHCの浄化に対して高活性であった。また、アルミナゾルから作製した粉末を用いた触媒の活性はこれらよりもはるかに低かった。したがって、本発明のジルコニアは有用である。 (Test Example 4)
In order to evaluate the characteristics of the monoclinic zirconia fine particle material of the present invention as a catalyst carrier, the fine particle solution of Example 12 was washed and dried, and then calcined in the air at 600 ° C. for 3 hours to obtain a powder. A powder prepared by firing a commercially available cerium oxide sol (manufactured by Nissan Chemical Industries, Ltd.) in the air at 600 ° C. for 3 hours was used as a comparative material (Comparative Example 3). Each of these was impregnated with 1% by weight of palladium using an aqueous solution of palladium nitrate (manufactured by Tanaka Kikinzoku), and heat-treated again in the air at 600 ° C. for 3 hours to carry palladium-supporting catalysts E (from Example 12) and F (comparative). (From Example 3) was prepared. Table 2 compares the results of measuring the temperature at which the purification rate of carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NO) becomes 80% by the same operation as in Test Example 1. The lower the temperature, the lower the temperature that can be purified, that is, the higher the activity of the catalyst. Comparing C and D, the catalyst using the zirconia of the present invention as a carrier was more active in purifying NO and HC than the catalyst using the cerium oxide sol material, which is generally considered to be highly active. In addition, the activity of the catalyst using the powder prepared from alumina sol was much lower than these. Therefore, the zirconia of the present invention is useful.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　本発明の正方晶ジルコニア微粒子材料及びその製造方法では、従来法に比べて工程が少なく、操作は容易であり該材料が簡易に得られる。また、低温でも良好な排ガス浄化特性を有する金属担持触媒の担体や添加剤として、正方晶ナノ粒子特性を利用し、環境浄化材に利用することができる。さらに、コロイド溶液自体は長期間保存しても安定であり、充填剤としてナノ粒子を利用する際、その原料として利用できる。ジルコニアを含む各種材料の化学的、光学的、物理的性質を利用した添加剤として種々の成分としてナノ粒子が応用できる。 The tetragonal zirconia fine particle material of the present invention and the method for producing the same have fewer steps than the conventional method, are easy to operate, and the material can be easily obtained. Further, as a carrier or an additive for a metal-supported catalyst having good exhaust gas purification characteristics even at a low temperature, tetragonal nanoparticles can be utilized and used as an environmental purification material. Furthermore, the colloidal solution itself is stable even when stored for a long period of time, and can be used as a raw material when nanoparticles are used as a filler. Nanoparticles can be applied as various components as additives that utilize the chemical, optical, and physical properties of various materials including zirconia.
　本発明の単斜晶ジルコニア微粒子材料は、全結晶相を１００％として含有する正方晶の割合が２０％以下であり、平均粒子径が５～３０ｎｍである材料であり、そのコロイド溶液自体は長期間保存しても安定である。充填剤や吸着剤としてナノ粒子を利用する際にはその原料として利用でき、またジルコニアを含む各種材料の化学的、光学的、電気磁気的、物理的、機械的性質を利用した材料であり、種々の成分とともに、ナノ粒子材の応用が可能である。さらには、その金属担持触媒の担体や添加剤としてナノ粒子及び膜特性を利用して、環境浄化材や機能材料に利用することができる。その製造方法は簡易であり、広く応用できる汎用性を有する。 The monoclinic zirconia fine particle material of the present invention is a material in which the proportion of tetragonal crystals containing 100% of the total crystal phase is 20% or less and the average particle size is 5 to 30 nm, and the colloidal solution itself is long. It is stable even if it is stored for a period of time. When nanoparticles are used as fillers and adsorbents, they can be used as raw materials, and are materials that utilize the chemical, optical, electromagnetic, physical, and mechanical properties of various materials including zirconia. Nanoparticle materials can be applied together with various components. Furthermore, nanoparticles and film properties can be utilized as carriers and additives for the metal-supporting catalyst, and can be used as environmental purification materials and functional materials. The manufacturing method is simple and has versatility that can be widely applied.

Claims (20)

  1. ジルコニア微粒子材料であって、以下の（１）又は（２）：
    （１）全結晶相を１００％として含有する単斜晶の割合が１０％以下であり、
    平均粒子径が２０ｎｍ以下であり、且つ、
    全結晶を１００％として含有する単結晶の割合が９０％以上である正方晶ジルコニア微粒子材料であるか、又は
    （２）全結晶相を１００％として含有する正方晶の割合が２０％以下であり、
    平均粒子径が５～３０ｎｍである単斜晶ジルコニア微粒子材料である、
    のいずれかを満たす、ジルコニア微粒子材料。     It is a zirconia fine particle material and has the following (1) or (2):
    (1) The proportion of monoclinic crystals containing 100% of the total crystal phase is 10% or less.
    The average particle size is 20 nm or less, and
    It is a tetragonal zirconia fine particle material in which the proportion of single crystals containing 100% of all crystals is 90% or more, or (2) the proportion of tetragonal crystals containing 100% of all crystal phases is 20% or less. ,
    A monoclinic zirconia fine particle material having an average particle size of 5 to 30 nm.
    Zirconia fine particle material that meets any of the above.
  2. 前記（１）を満たす、請求項１に記載のジルコニア微粒子材料。 The zirconia fine particle material according to claim 1, which satisfies the above (1).
  3. 全結晶相を１００％として含有する単斜晶の割合が５％以下である、請求項２に記載のジルコニア微粒子材料。 The zirconia fine particle material according to claim 2, wherein the proportion of monoclinic crystals containing 100% of the total crystal phase is 5% or less.
  4. 平均粒子径が０．１～１０ｎｍである、請求項２又は３に記載のジルコニア微粒子材料。 The zirconia fine particle material according to claim 2 or 3, wherein the average particle size is 0.1 to 10 nm.
  5. 平均粒子径が０．２～５ｎｍである、請求項２～４のいずれか１項に記載のジルコニア微粒子材料。 The zirconia fine particle material according to any one of claims 2 to 4, which has an average particle size of 0.2 to 5 nm.
  6. 含有する単結晶の割合が９５％以上である、請求項２～５のいずれか１項に記載のジルコニア微粒子材料。 The zirconia fine particle material according to any one of claims 2 to 5, wherein the ratio of the single crystal contained is 95% or more.
  7. 前記（２）を満たす、請求項１に記載のジルコニア微粒子材料。 The zirconia fine particle material according to claim 1, which satisfies the above (2).
  8. 全粒子数を１００％として、厚みが３ｎｍ以下であるシート状材料の割合が５０％以上である、請求項７に記載のジルコニア微粒子材料。 The zirconia fine particle material according to claim 7, wherein the ratio of the sheet-like material having a thickness of 3 nm or less is 50% or more, where the total number of particles is 100%.
  9. 全粒子数を１００％として、不定形な形状を有する粒子の割合が６０％以上である、請求項７又は８に記載の単斜晶ジルコニア微粒子材料。 The monoclinic zirconia fine particle material according to claim 7 or 8, wherein the proportion of particles having an amorphous shape is 60% or more, where the total number of particles is 100%.
  10. 全粒子数を１００％として、不規則な方向に複数の突起が伸びる形状を有する粒子の割合が５０％以上である、請求項７～９のいずれか１項に記載のジルコニア微粒子材料。 The zirconia fine particle material according to any one of claims 7 to 9, wherein the proportion of particles having a shape in which a plurality of protrusions extend in irregular directions is 50% or more, assuming that the total number of particles is 100%.
  11. 請求項１～１０のいずれか１項に記載のジルコニア微粒子材料を含むガス処理用触媒。 A catalyst for gas treatment containing the zirconia fine particle material according to any one of claims 1 to 10.
  12. 前記ジルコニア微粒子材料にＰｔ、Ｐｄ、Ｒｈ、Ａｕ、Ｃｕ、Ｆｅ、Ｎｉ、Ａｇ及びＣｅから選択された金属、前記金属を含む合金、並びに前記金属の酸化物よりなる群から選ばれる少なくとも１種の微粒子を担持する、請求項１１に記載のガス処理用触媒。 At least one selected from the group consisting of a metal selected from Pt, Pd, Rh, Au, Cu, Fe, Ni, Ag and Ce, an alloy containing the metal, and an oxide of the metal in the zirconia fine particle material. The gas treatment catalyst according to claim 11, which carries fine particles.
  13. 請求項１～１０のいずれか１項に記載の正方晶ジルコニア微粒子材料、又は請求項１１若しくは１２に記載のガス処理用触媒を含有する、水溶液又はコロイド溶液。 An aqueous solution or a colloidal solution containing the tetragonal zirconia fine particle material according to any one of claims 1 to 10 or the gas treatment catalyst according to claim 11 or 12.
  14. 請求項７～１０のいずれか１項に記載のジルコニア微粒子材料、又は請求項１１若しくは１２に記載のガス処理用触媒を含有する、ジルコニアナノシート材料。 A zirconia nanosheet material containing the zirconia fine particle material according to any one of claims 7 to 10 or the gas treatment catalyst according to claim 11 or 12.
  15. 請求項２～６のいずれか１項に記載のジルコニア微粒子材料、請求項１１若しくは１２に記載のガス処理用触媒、又は請求項１３に記載の水溶液又はコロイド溶液の製造方法であって、
    水溶性ジルコニウム塩及び水溶性界面活性剤を含む水溶液をアルカリ性として沈殿物含有水溶液を得る第１工程と、
    前記沈殿物含有水溶液を９０℃～１７０℃で加熱する第２工程と、
    を備える、製造方法。     The method for producing a zirconia fine particle material according to any one of claims 2 to 6, the gas treatment catalyst according to claim 11 or 12, or the aqueous solution or colloidal solution according to claim 13.
    The first step of obtaining a precipitate-containing aqueous solution by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline.
    The second step of heating the precipitate-containing aqueous solution at 90 ° C. to 170 ° C.
    A manufacturing method.
  16. 前記第２工程における加熱保持時間が１０分以上２４時間以下である、請求項１５に記載の製造方法。 The production method according to claim 15, wherein the heating holding time in the second step is 10 minutes or more and 24 hours or less.
  17. 請求項７～１０のいずれか１項に記載の単斜晶ジルコニア微粒子材料、請求項１１若しくは１２に記載のガス処理用触媒、請求項１３に記載の水溶液若しくはコロイド溶液、又は請求項１４に記載のジルコニアナノシート材料の製造方法であって、
    水溶性ジルコニウム塩及び水溶性界面活性剤を含む水溶液をアルカリ性として沈殿物含有水溶液を得る第１工程と、
    前記沈殿物含有水溶液を１８０℃～６００℃で１２時間以上加熱する第２工程と、
    を備える、製造方法。     The monoclinic zirconia fine particle material according to any one of claims 7 to 10, the gas treatment catalyst according to claim 11 or 12, the aqueous solution or colloidal solution according to claim 13, or claim 14. This is a method for manufacturing zirconia nanosheet materials.
    The first step of obtaining a precipitate-containing aqueous solution by making an aqueous solution containing a water-soluble zirconium salt and a water-soluble surfactant alkaline.
    The second step of heating the precipitate-containing aqueous solution at 180 ° C. to 600 ° C. for 12 hours or more, and
    A manufacturing method.
  18. 前記第２工程の後、
    該水溶液内の固形分を分離後、有機溶媒に分散させることで前記コロイド溶液を得る第３工程
    を備える、請求項１５～１７のいずれか１項に記載の製造方法。     After the second step,
    The production method according to any one of claims 15 to 17, further comprising a third step of obtaining the colloidal solution by separating the solid content in the aqueous solution and then dispersing it in an organic solvent.
  19. 前記第２工程又は第３工程の後、溶液の溶媒を除去することで前記ジルコニア微粒子材料又は前記ガス処理用触媒を得る、請求項１５～１８のいずれか１項に記載の製造方法。 The production method according to any one of claims 15 to 18, wherein the zirconia fine particle material or the catalyst for gas treatment is obtained by removing the solvent of the solution after the second step or the third step.
  20. 前記第２工程又は第３工程の後、溶液を基板上に添加又は溶液内に基板を浸漬し取り出すことで前記ジルコニアナノシート材料を得る、請求項１５～１８のいずれか１項に記載の製造方法。 The production method according to any one of claims 15 to 18, wherein after the second step or the third step, the zirconia nanosheet material is obtained by adding a solution onto the substrate or immersing the substrate in the solution and taking it out. ..
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