WO2016143385A1 - Hydrogen gas detecting member, method for manufacturing same, and hydrogen gas detecting system - Google Patents

Hydrogen gas detecting member, method for manufacturing same, and hydrogen gas detecting system Download PDF

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Publication number
WO2016143385A1
WO2016143385A1 PCT/JP2016/051200 JP2016051200W WO2016143385A1 WO 2016143385 A1 WO2016143385 A1 WO 2016143385A1 JP 2016051200 W JP2016051200 W JP 2016051200W WO 2016143385 A1 WO2016143385 A1 WO 2016143385A1
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Prior art keywords
hydrogen gas
containing layer
gas detection
detection member
tungsten oxide
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PCT/JP2016/051200
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French (fr)
Japanese (ja)
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高橋　篤
啓介 溝口
前澤　明弘
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コニカミノルタ株式会社
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Publication of WO2016143385A1 publication Critical patent/WO2016143385A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G01N31/10—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using catalysis
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G01N31/22—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators

Definitions

  • the present invention relates to a hydrogen gas detection member, a manufacturing method thereof, and a hydrogen gas detection system. More specifically, the present invention relates to a hydrogen gas detection member using a gas chromic material for hydrogen gas detection, a manufacturing method thereof, and a hydrogen gas detection system.
  • Hydrogen is a clean energy source that does not emit carbon dioxide, harmful sulfides, and nitrides, and only produces water when burned. Hydrogen gas can be easily produced in various ways. Can do. Therefore, in the near future, hydrogen gas is expected to be supplied as an important energy source to ordinary households, hydrogen gas stations, and industrial facilities.
  • hydrogen as a clean energy source has a risk of explosion in an atmosphere in which oxygen is present. For example, in the air, there is a possibility of explosion when the hydrogen gas concentration reaches about 4% by volume (volume percentage) or more. It is said that.
  • hydrogen gas sensors used for detecting hydrogen gas include semiconductor sensors, solid electrolyte sensors, contact heat conversion sensors, thermal conduction sensors, light detection sensors, point sensors, optical waveguides, and optical fibers.
  • a planar sensor having a detection film for optically detecting hydrogen in the cladding of the metal it is difficult to find a gas leaking portion containing hydrogen.
  • a hydrogen sensor such as a semiconductor sensor using tin oxide is originally a sensor for quantitatively measuring the hydrogen concentration in the atmosphere, and is not suitable for use in finding a leak point of hydrogen gas.
  • the structure is complicated and the price is high.
  • Japanese Patent Application Laid-Open No. 2004-53540 discloses a hydrogen sensor material in which a catalytic metal element-containing layer is formed on the surface of a magnesium thin film, and is based on the fact that the electrical resistance or optical properties change by reacting with hydrogen. Hydrogen sensor materials that detect hydrogen are disclosed.
  • the hydrogen concentration is determined based on the resistance detector that measures the electrical resistance of the hydrogen sensor or the detection result of the resistance detector.
  • An arithmetic processing device to be derived is required, and when measuring optical properties, a measurement system using a semiconductor laser or a photodiode is required, and the structure becomes complicated.
  • a photodetection type hydrogen sensor using a transition metal oxide (WO 3 , MoO 3 , TiO 2, etc.) having a gas chromic property that is colored by hydrogen gas adsorption is, for example, -67218.
  • a tungsten oxide (HxWO 3 ) thin film having platinum or platinum deposited on its surface as a catalyst metal is colored and exhibits gaschromic properties when exposed to an atmosphere containing hydrogen at room temperature (around 20 ° C.).
  • the coloring rate by hydrogen adsorption of the tungsten oxide thin film is 50% or more for visible light (red light) having a wavelength of 630 nm. Therefore, hydrogen can be detected by utilizing the change in optical transmittance due to hydrogen adsorption of the tungsten oxide thin film, and the tungsten oxide thin film is expected to be an alternative material for tin oxide.
  • the hydrogen detection material composed of the above-described tungsten oxide thin film has a problem in that the hydrogen detection performance is remarkably deteriorated due to adhesion of organic substances or the like to the surface of the catalyst metal layer when left in the air for a long period of time.
  • the coating is applied to the surface of a structure (for example, a gas tank, a gas pipe, etc.) that handles a fuel gas such as hydrogen gas, and changes its color when it comes into contact with the leaking fuel gas.
  • a fuel gas leak detection coating film using powder, alkoxysilane as a binder, hydrochloric acid as a catalyst, and ethyl alcohol, water and isopropyl alcohol as a solvent is disclosed (for example, see Patent Document 1).
  • Patent Document 1 has a low detection sensitivity for leakage of hydrogen gas and an extremely slow response speed for detection of hydrogen gas in an environment near room temperature, which causes a problem for practical use. I have it.
  • a coating film pigment for hydrogen gas detection in which the temperature changes is known.
  • the pigment is composed of an aggregate of crystalline fine particles mainly composed of tungsten oxide, and a coating film pigment for detecting hydrogen gas containing a catalytic metal in an oxidized state on the surface of the crystalline fine particle tungsten oxide and a hydrogen gas applied with the same.
  • a detection tape is disclosed (for example, refer to Patent Document 2).
  • the present invention has been made in view of the above-mentioned problems, and a solution to the problem is a hydrogen gas detection member having a large change in light transmittance and hue with respect to the hydrogen gas concentration, a high detection sensitivity, and a method for manufacturing the same. It is providing the hydrogen gas detection system which equipped.
  • the inventor has a cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer, and the cerium oxide-containing layer and the tungsten oxide-containing layer are adjacent to each other.
  • the catalytic metal element-containing layer is disposed on the opposite side of the tungsten oxide-containing layer from the surface facing the cerium oxide-containing layer, and the light absorption characteristics change according to the change in hydrogen gas concentration. It has been found that the hydrogen gas detection member can provide a hydrogen gas detection member having a high detection sensitivity with a large change in light transmittance and hue with respect to the hydrogen gas concentration.
  • a member for detecting hydrogen gas wherein light absorption characteristics change according to a change in hydrogen gas concentration.
  • the catalytic metal element-containing layer contains a metal element selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, cobalt, nickel and copper.
  • the hydrogen gas detection member composed of the cerium oxide-containing layer, the tungsten oxide-containing layer, and the catalytic metal element-containing layer is in the form of a thin film sheet, any one of items 1 to 3 The hydrogen gas detection member according to item.
  • the hydrogen gas detection member composed of the cerium oxide-containing layer, the tungsten oxide-containing layer, and the catalytic metal element-containing layer is in the form of particles, and the catalytic metal element-containing layer is outside the tungsten oxide-containing layer.
  • the particulate hydrogen gas detection member has a core-shell structure consisting of three layers, the core part is composed of a cerium oxide-containing layer, and the shell part is composed of a tungsten oxide-containing layer and a catalytic metal element-containing layer. 6.
  • a hydrogen gas detection member according to any one of items 1 to 6, A light source unit for irradiating the hydrogen gas detection member with a specific wavelength; An optical measuring device for measuring the light passing through the hydrogen gas detecting member; A detection device for detecting whether or not the light absorption characteristic measured by the optical measurement device exceeds a specified value; An alarm device that issues an alarm based on information detected by the detection device; and A hydrogen gas detection system comprising:
  • the hydrogen gas detection system further comprising a gas supply control unit that blocks supply of hydrogen gas based on information detected by the detection device.
  • a hydrogen gas detection member having a large light transmittance change and hue change with respect to the hydrogen gas concentration and having a high detection sensitivity, a manufacturing method thereof, and a hydrogen gas detection system including the same are provided. can do.
  • a catalyst for example, , Palladium, platinum, etc.
  • a coating liquid containing the hydrogen gas detection member of the present invention is prepared and applied to a tank, cylinder, equipment used, pump, valve, piping, or storage container containing hydrogen gas to form a hydrogen gas detection coating film.
  • the light absorption spectrum (light absorption characteristics) of the coating film for hydrogen gas detection changes greatly. Therefore, hydrogen can be detected visually or by optical inspection means (eg, camera, spectrophotometer, etc.). It can detect gas quickly and take quick measures against hydrogen gas leakage.
  • Schematic sectional view showing an example of the configuration of the hydrogen gas detection member Schematic sectional view showing another example of the configuration of the hydrogen gas detection member
  • Schematic sectional view showing another example of the configuration of the hydrogen gas detection member Diagram showing an example of the production flow of core / shell type hydrogen gas detection particles
  • the figure which shows an example of the manufacturing process of the particle for hydrogen gas detection of a core shell type Schematic showing an example of the basic configuration of the hydrogen gas detection system (light transmission type)
  • Schematic showing an example of the basic configuration of the hydrogen gas detection system (reflection type) Schematic showing an example of a hydrogen gas detection system using a hydrogen gas detection member
  • ⁇ is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
  • the hydrogen gas detection member of the present embodiment includes a cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer, wherein the cerium oxide-containing layer and the tungsten oxide-containing layer are disposed adjacent to each other, and the catalyst
  • the metal element-containing layer is disposed on the opposite side of the tungsten oxide-containing layer from the surface facing the cerium oxide-containing layer, and the light absorption characteristic changes according to a change in hydrogen gas concentration.
  • hydrogen gas detection methods using gas chromic materials that react with hydrogen are roughly classified as follows: 1) A combination of a hydrogenation catalyst and a metal oxide, and a method of detecting a change in the transmittance of the metal oxide and color shading when reacting with hydrogen gas, 2) A combination of a hydrogenation catalyst and a metal alloy, and a method for detecting by a change in the transmittance of the metal alloy when reacting with hydrogen gas, 3) A combination of a hydrogenation catalyst and an organic dye, and a method of detecting by a shift in the absorption wavelength of the organic dye (change in hue) when reacting with hydrogen gas,
  • the hydrogen gas detection member of this embodiment is a method in which the hydrogenation catalyst described in the above item 1) is combined with a metal oxide.
  • the tungsten oxide is supplied into a tungsten oxide-containing layer disposed therebelow, and the tungsten oxide has a pentavalent structure called a so-called tungsten bronze structure in which protons (H + ) are inserted from a normal hexavalent state. Change to state.
  • the hydrogen gas detecting member absorbs visible light in the wavelength range of 600 to 800 nm by the intervalence transfer absorption by the electrons transitioning between the hexavalent state and the pentavalent state. It changes to the coloring state which has. At this time, the tungsten oxide-containing layer, which is colorless and transparent in the normal state, is in a state of exhibiting blue (tungsten bronze).
  • the cerium oxide-containing layer in the lower part adjacent to the tungsten oxide-containing layer, oxygen atoms of tungsten oxide are introduced when hydrogen gas is introduced. Is easily attracted to cerium atoms existing in adjacent layers, the structure becomes unstable, and easily changes from a colorless tungsten oxide (H x WO 3 ) to a blue tungsten oxide (H y WO 3 ) as a crystal structure. It is assumed that the hydrogen gas detection sensitivity has greatly increased.
  • x is a numerical value within a range of 0.5 or more and less than 0.8
  • y is within a numerical value range of 0.8 or more and 1.0 or less.
  • the hydrogen gas detection member of the present embodiment includes a cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer, and the cerium oxide-containing layer and the tungsten oxide-containing layer are disposed adjacent to each other,
  • the catalytic metal element-containing layer is disposed on the opposite side of the tungsten oxide-containing layer from the surface facing the cerium oxide-containing layer.
  • the preferable form of the member for hydrogen gas detection is a member of a particle form or a thin film sheet form.
  • FIG. 1A and FIG. 1B are schematic sectional views showing an example of the configuration of a conventional hydrogen gas detection member in the form of a thin film sheet and the hydrogen gas detection member of the present embodiment.
  • a thin-film sheet-like hydrogen gas detection member (1A) shown in FIG. 1A is a conventional hydrogen gas detection member, and a tungsten oxide-containing layer (4) for detecting hydrogen gas and a catalyst on a substrate (2).
  • the metal element-containing layer (5) is configured to be laminated, the hydrogen gas detection member having such a configuration has a problem that the detection sensitivity with respect to the leaked hydrogen gas concentration is low.
  • the thin-film sheet-shaped hydrogen gas detection member (1B) shown in FIG. 1B increases the gaschromic effect of the tungsten oxide-containing layer (4) on the substrate (2), thereby increasing the detection sensitivity.
  • a cerium oxide-containing layer (3) is disposed, and a tungsten oxide-containing layer (4) for detecting hydrogen gas and a catalytic metal element-containing layer (5) are laminated thereon.
  • the hydrogen gas detecting member (1B) configured to provide such a cerium oxide-containing layer (3), in the tungsten oxide-containing layer (4) when hydrogen gas is detected, H x WO 3 (light yellow ) To H y WO 3 (blue) can be increased, and as a result, the detection sensitivity to the hydrogen gas concentration can be increased.
  • the cerium oxide-containing layer (3) and the tungsten oxide-containing layer (4) are adjacent to each other, and the crystal grain boundary ( It is characteristic that Gb) is formed.
  • FIG. 2 is a schematic cross-sectional view of a particulate hydrogen gas detection member having a core-shell structure as another example of the configuration of the hydrogen gas detection member.
  • a cerium oxide-containing layer (3) is formed on the core portion, and a tungsten oxide-containing layer (4) is coated on the surface portion as a first shell portion. Further, the catalyst-metal element-containing layer (5) is supported as a second shell portion on the surface portion, in other words, outside the tungsten oxide-containing layer (4), and particles having a core-shell type structure are supported.
  • the cerium oxide-containing layer (3) and the tungsten oxide-containing layer (4) are disposed adjacent to each other, and the grain boundary It is important to form (Gb).
  • the member for hydrogen gas detection has a thin film sheet-like hydrogen gas detection member as shown in the said FIG. 1B, or a core-shell type structure as shown in FIG. It is preferably in the form of particles.
  • the manufacturing method of the member for hydrogen gas detection faces the cerium oxide containing layer of the process of arrange
  • particulate hydrogen gas detection member having a thin film sheet shape and a core / shell structure
  • the thin-film sheet-like hydrogen gas detection member (1B) has, on the substrate (2), a cerium oxide-containing layer (3), a tungsten oxide-containing layer (4) for detecting hydrogen gas, and The catalyst metal element-containing layer (5) is laminated in this order.
  • Suitable substrates for such conditions include, for example, polyester (for example, polyethylene terephthalate), polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, polyamide, nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, Polyether sulfone, silicon resin, polyacetal resin, fluororesin, cellulose derivatives, polymer films such as polyolefin, plate substrates, glass substrates such as quartz glass, and the like are preferably used.
  • polyester for example, polyethylene terephthalate
  • polyimide polymethyl methacrylate
  • polystyrene polypropylene
  • polyethylene polyamide
  • nylon polyvinyl chloride
  • polyvinylidene chloride polycarbonate
  • Polyether sulfone silicon resin
  • polyacetal resin fluororesin
  • cellulose derivatives polymer films
  • polymer films such as polyolefin, plate substrates, glass substrates such as quartz glass, and the
  • the cerium oxide-containing layer (3) and the tungsten oxide-containing layer (4) are each preferably a thin film having a thickness in the range of 25 to 500 nm.
  • the thickness of the tungsten oxide-containing layer (4) is 25 nm or more, it is possible to reliably detect a change in transmittance and a change in hue when in contact with hydrogen gas.
  • each thickness is 500 nm or less, generation
  • the thickness of the catalyst metal element-containing layer (5) to be deposited is preferably in the range of 1 to 20 nm. If the thickness of the catalytic metal element-containing layer (5) is 20 nm or less, the shielding of incident light by the catalyst itself can be suppressed, and discrimination of changes in transmitted light intensity is not hindered. Moreover, if the thickness of the catalyst metal element-containing layer (5) is 1 nm or more, a change in transmitted light intensity that can be easily discriminated by visual observation can be obtained, and hydrogen gas can be detected.
  • the method for forming the cerium oxide-containing layer (3) and the tungsten oxide-containing layer (4) is not particularly limited, and the sputtering method is used in the examples. Methods, DC sputtering methods, vacuum deposition methods, electron beam deposition methods, chemical vapor deposition methods, pulsed laser deposition methods (PLD methods), plating methods, sol-gel methods, and the like can be appropriately selected and applied.
  • the cerium oxide-containing layer (3), the tungsten oxide-containing layer (4), and the catalytic metal element-containing layer (5) are formed by sputtering, sputtering is performed using cerium oxide, tungsten, and catalytic metal as sputtering targets, respectively. Then, a cerium oxide thin film and a tungsten oxide thin film are formed on the surface of the substrate, and then a catalytic metal is deposited on the surface of the tungsten oxide thin film.
  • Sputtering is preferably a mixed atmosphere of argon and oxygen.
  • the substrate temperature at the time of sputtering is preferably room temperature (20 ° C.). Since the leakage of hydrogen gas is detected by a visual color change, the light absorption characteristic required for the hydrogen gas detection member is that the transmittance changes by 50% or more due to hydrogen adsorption. preferable.
  • the oxygen gas pressure is 14 to 80 mPa.
  • the argon gas pressure is preferably 130 to 170 mPa.
  • the oxygen gas pressure is 15 to 40 mPa and the argon gas pressure is 140 to 160 mPa.
  • the ratio of oxygen gas is The gas pressure (the sum of oxygen gas pressure and argon gas pressure) may be controlled within a range of 10 to 30%.
  • the catalyst metal can be deposited by a pulse laser deposition method, a high frequency sputtering method, a direct current sputtering method, a molecular beam epitaxy method, or a vacuum evaporation method, and any metal can be deposited at a temperature lower than the heat resistant temperature of the substrate.
  • the method may be used.
  • the deposition conditions are preferably an atmosphere in which the sputtering power is 25 W to 50 W, the substrate is at room temperature, and the argon gas pressure is 130 to 170 mPa.
  • the metal element forming the catalyst metal is preferably a metal element selected from noble metal elements (specifically, platinum, palladium, rhodium, iridium, ruthenium, and osmium), cobalt, nickel, and copper, It is preferable to use platinum, palladium, cobalt, nickel, or copper from the viewpoint that hydrogen gas can be detected more effectively. Further, among these, a plurality of types of metal elements may be used.
  • the main manufacturing process is to form core particles containing cerium oxide, to form a first shell portion containing tungsten oxide on the core particles, and on the first shell portion.
  • (Process a) A step of crystallizing and growing cerium oxide microcrystals in an aqueous solution using cerium nitrate, nitric acid, ammonia or the like to form core particles (core portion) composed of cerium oxide.
  • Step a The first stage prepares an initial solution that is a solution of a cerium (III) salt.
  • a cerium (III) salt for example, cerium (III) nitrate, cerium (III) chloride, cerium (III) sulfate, cerium carbonate (III) and a mixture of these salts (such as a nitrate / chloride mixture) are used.
  • cerium (III) nitrate for example, cerium (III) nitrate, cerium (III) chloride, cerium (III) sulfate, cerium carbonate (III) and a mixture of these salts (such as a nitrate / chloride mixture) are used.
  • cerium (III) nitrate for example, cerium (III) nitrate, cerium (III) chloride, cerium (III) sulfate, cerium carbonate (III) and a mixture of these salts (such as a nitrate / chloride mixture.
  • cerium (III) nitrate as a representative example of the cerium (III) salt will be described.
  • nitric acid is used to control the pH of the mixed solution that is the starting solution.
  • the mixed liquid prepared in the first stage can be degassed in advance by passing an inert gas.
  • an inert gas for example, nitrogen gas or argon gas can be applied.
  • the mixed solution and the base aqueous solution are reacted.
  • the aqueous base solution include alkali metal or alkaline earth metal hydroxide, and aqueous ammonia. Secondary amines, tertiary amines or quaternary amines can also be used. Among the above, amines or aqueous ammonia is preferable. This reduces the risk of contamination by alkali metal cations or alkaline earth metal cations by using amines and aqueous ammonia.
  • the mixed solution prepared above is added to this base solution (for example, aqueous ammonia) with stirring. Also at this time, degassing can be performed by aeration using an inert gas.
  • the second stage is preferably performed in an inert atmosphere while sweeping with an inert gas in either a closed reactor or a semi-closed reactor. Contact is generally carried out in a stirred reactor.
  • This second stage is generally performed at ambient temperature (20-25 ° C.) or at a maximum temperature of 50 ° C.
  • the prepared cerium oxide suspension is heat-treated. This heat treatment is performed for about 1 to 5 hours while maintaining the temperature in the range of about 60 to 95 ° C. The duration of this process can be from a few minutes to a few hours. This heat treatment is also performed in an inert atmosphere.
  • Acidification is generally performed by adding an acid after cooling the suspension obtained at the end of the third stage.
  • the acid either an inorganic acid or an organic acid can be used, but nitric acid is preferably used.
  • the amount of acid added is such that the pH of the suspension after acidification is in the range of 2-4. This operation can be performed in a normal atmospheric environment.
  • Washing is performed following acidification. Its purpose is to remove soluble species, in principle salts, from the suspension, which can be carried out in various ways, with or without separating the solid / liquid.
  • Step b As a first step, an aqueous solution containing tungstate is added to a suspension containing core particles composed of the prepared cerium oxide to prepare a suspension.
  • an acid is added to the suspension containing the cerium oxide core particles and the tungstate.
  • the acid to be used either an inorganic acid or an organic acid can be used, but nitric acid is preferably used.
  • the amount of acid added is such that the pH of the suspension after acidification is 1 or less.
  • the acid is slowly added over 20 to 60 minutes with stirring at room temperature to form a first shell layer of tungstic acid (H 2 WO 4 ) on the surface of the cerium oxide core particles.
  • step c a compound containing a catalytic metal element, such as H 2 PtCl 6 / 6H 2 O, PdCl, is added to the suspension containing the core-shell particles A composed of the cerium oxide / tungstic acid (H 2 WO 4 ). 2 , an aqueous solution containing Co (NO 3 ) 2 , Ni (NO 3 ) 2 , Cu (NO 3 ) 2, etc.
  • a compound containing a catalytic metal element such as H 2 PtCl 6 / 6H 2 O, PdCl
  • tungstic acid H 2 WO 3
  • a second shell layer supporting a catalytic metal element is formed on the surface of the layer, the core particles are cerium oxide, the first shell layer is tungstic acid (H 2 WO 4 ), and the second shell layer A suspension containing the core-shell particles B composed of a catalytic metal element is prepared.
  • Step e Conversion of tungstic acid (H 2 WO 4 ) to tungsten oxide (H x WO 3 ) by baking treatment: Step e)
  • the suspension containing the core / shell particles B prepared above was removed of moisture using an evaporator or the like, and the obtained core / shell particles B were dried at 80 to 150 ° C. for 1 to 5 hours.
  • the tungstic acid (H 2 WO 4 ) layer was subjecting the tungstic acid (H 2 WO 4 ) layer to a tungsten oxide (H x WO 3 ) layer by performing a baking treatment for 30 minutes to 3 hours in a temperature range of 150 to 400 ° C.
  • the shell structure hydrogen gas detection member (1P) can be obtained.
  • the diameter of the cerium oxide particles constituting the core is in the range of 50 to 200 nm, the thickness of the tungsten oxide layer is in the range of 25 to 100 nm, and the thickness of the catalytic metal element layer is 1 to 20 nm. It is preferable to be within the range.
  • FIG. 4 is a diagram showing a specific flow of the manufacturing process of core / shell particles of hydrogen gas detection particles.
  • step a and step a1 First, core particles composed of cerium oxide are prepared using step a having the reaction vessel (101) shown in FIG. 4 and step a1 having an additive preparation vessel (105).
  • a cerium nitrate aqueous solution and a nitric acid aqueous solution are added to the preparation kettle (105) of step a1, and the mixture (106) is prepared by stirring with a stirrer (107) while venting with N 2 gas.
  • an aqueous ammonia solution is added as a mother liquor (102) to the reaction kettle (101), and stirred with a stirrer (103) while venting with N 2 gas.
  • the mixed solution (106) of the cerium nitrate aqueous solution and the nitric acid aqueous solution is transferred from the preparation kettle (105) of step a1 into the aqueous ammonia solution in the reaction kettle (101) using an N 2 gas atmosphere. Add with stirring under to prepare a suspension.
  • the suspension is heated to a temperature range of 60 to 90 ° C., and this state is maintained for a certain time.
  • a core-shell type particle is prepared by coating tungstic acid as the first shell layer on the surface of the core particle composed of cerium oxide prepared in a.
  • a sodium tungstate aqueous solution (116) is prepared in a preparation kettle (115). Further, although not shown in the figure, a nitric acid aqueous solution (116b) is prepared in the preparation kettle (115b) of another system.
  • the suspension (104) containing the cerium oxide particles (core particles) prepared above is stored, and while the suspension (104) is stirred, using the liquid feed pump (118), A sodium tungstate aqueous solution (116) is added from the preparation kettle (115).
  • cerium oxide (CeO 2 ) is a core particle, and includes a core-shell particle in which a first shell portion of tungstic acid (H 2 WO 4 ) is formed on the surface.
  • a suspension (112, CeO 2 / H 2 WO 4 suspension) is prepared.
  • step c and step c1 Formation of catalytic metal element-containing layer (second shell part) on outermost surface: step c and step c1)
  • step c having the reaction kettle (121) shown in FIG. 4 and the step c1 having the preparation kettle (125)
  • a catalyst metal element-containing layer is formed on the surface of the prepared core-shell type particles.
  • the final core-shell type particles are prepared by being supported as a shell part.
  • Preparation kettle (125) for example, to prepare a H 2 PtCl 6 ⁇ 6H 2 O aqueous solution as a catalyst metal element-containing compound (126).
  • the CeO 2 / H 2 WO 4 suspension reactor (121) (112), using a feeding pump (128), prepared kettle (125) from H 2 PtCl 6 ⁇ 6H 2 O solution (126 ) Is added over a predetermined time with stirring, and a catalytic metal element-containing layer (second shell part) containing platinum as a catalyst on the tungstic acid (H 2 WO 4 ) layer (first shell part) ) Supported CeO 2 / H 2 WO 4 / Pt suspension (127).
  • the metal element that forms the catalyst metal is preferably a metal element selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, cobalt, nickel, and copper. It is preferable to use palladium, cobalt, nickel, or copper from the viewpoint that hydrogen gas can be detected more effectively. Of these, a plurality of types of metal elements may be used.
  • the powder from which moisture has been removed in the firing step (step e) is heat-dried using a firing device (141), and then subjected to a firing treatment in a temperature range of 150 to 400 ° C., thereby converting H 2 WO 4 into H x converted to WO 3, to prepare a CeO 2 / H x WO 3 / Pt hydrogen gas detecting member is a core-shell particles composed of (1P).
  • x takes a numerical value of 0.5 or more and less than 0.8.
  • ⁇ Basic configuration of hydrogen gas detection system> 5A and 5B show an example of a basic configuration of a hydrogen gas detection system using a hydrogen gas detection member.
  • the hydrogen gas detection and measurement apparatus (50) shown in FIG. 5A shows an example of a hydrogen gas detection system using a light transmission type hydrogen gas detection member (1), and a light transmissive substrate is provided at the center.
  • a hydrogen gas detection member (1) composed of a cerium oxide-containing layer (3), a tungsten oxide-containing layer (4), and a catalytic metal element-containing layer (5) is disposed, and a light source section (51 )
  • a spectrophotometer (52) for measuring the amount of light (transmitted light) that has passed through the hydrogen gas detection member (1) is arranged on the right side.
  • a wavelength measured by the spectrophotometer (52) it is preferable to use light having a wavelength of 600 nm which is highly sensitive for detecting a change in transmittance of the tungsten oxide-containing layer (4).
  • air from which hydrogen gas has been removed flows from the gas inlet (54) into the hydrogen gas detection and measurement device (50), and flows out from the gas outlet (55).
  • Visible light (L) is irradiated, and light transmittance TP1 (ratio of light transmitted light to total irradiated light (%)) in an air atmosphere with light having a wavelength of 600 nm is measured.
  • the gas flowing into the hydrogen gas detection / measurement device (50) is changed to air containing 1% by volume hydrogen gas, and similarly, light is transmitted through light having a wavelength of 600 nm when exposed to 1% by volume hydrogen gas.
  • the rate TP2 is measured, and the change in light transmittance (%) of each hydrogen gas detection member with respect to the hydrogen gas concentration is measured according to the following formula (1). This is a measure of the hydrogen gas detection capability of the hydrogen gas detection member ( Calculated as a calibration curve).
  • the hydrogen gas detection and measurement apparatus (50) shown in FIG. 5B shows an example of a hydrogen gas detection system when the reflective hydrogen gas detection member (1) is used, unlike the configuration shown in FIG. 5A.
  • the substrate (2a) is made of a light-impermeable material and the reflected light is measured by a spectrophotometer (52).
  • FIG. 6 shows an example of a hydrogen gas detection system using a hydrogen gas detection member.
  • the hydrogen gas detection member can be used effectively in an environment where hydrogen gas is used, for example, in an environment where a hydrogen gas cylinder (C) and a hydrogen gas tank (D) are arranged. it can.
  • the member for detecting hydrogen gas is in the form of a thin film sheet, it can be disposed on the wall surface (B) of the room, the surface of the hydrogen gas cylinder (C), the surface of the hydrogen gas tank (D) or the entire surface. .
  • the hydrogen gas detection member of the present invention is in the form of core / shell type particles, it is dispersed in a binder and prepared as a paint, and then the indoor ceiling (A), wall surface (B), hydrogen gas cylinder (C). Or the outer wall of the hydrogen gas tank (D), the pipe (E), the valve (F), the pump (G), etc. of the hydrogen gas tank (D).
  • the hydrogen gas detection system of the present embodiment includes an optical measurement device (62) for detecting a change in light transmittance and hue of a hydrogen gas detection member installed in the hydrogen gas container installation chamber (61), and an optical measurement.
  • leakage of hydrogen gas detected by hydrogen gas detection members installed in various places is detected by the optical measurement device (62) and the detection device (63).
  • the change in the hue of the hydrogen gas detection member is measured by receiving the reflected light using the optical measurement device (62), and the color tone and the amount of reflected light of the reflected light are measured by the detection device (63).
  • the detection device (63) determines that there is a leak
  • the alarm device (64) issues an alarm based on the information transmitted from the detection device (63), and the valve (F) that is the source of hydrogen gas leakage
  • the gas supply control unit (65) transmits a control signal (66) for shutting off the power supply and stopping the pump (G).
  • Example 1 Production of thin-film sheet-like hydrogen gas detection member >> In accordance with the following method, thin film sheet-like hydrogen gas detection members 1 to 6 were produced.
  • a quartz substrate having a size of 10 mm ⁇ 10 mm and a thickness of 1 mm was used as the substrate (2).
  • cerium oxide-containing layer (3) having a layer thickness of 100 nm was deposited on the substrate (2) by sputtering.
  • Sputtering was performed by DC pulse sputtering of cerium oxide (CeO 2 ) with an Ar gas partial pressure of 120 mPa and an oxygen gas partial pressure of 50 mPa, with a power of 50 W at room temperature (25 ° C.) to a layer thickness of 100 nm.
  • the target-substrate distance was 100 mm.
  • tungsten oxide-containing layer (4, H x WO 3 ) having a layer thickness of 100 nm is formed on the formed cerium oxide-containing layer (3) by sputtering similar to the above using metal tungsten (W) as a target.
  • Ar gas partial pressure was 130 mPa and oxygen gas partial pressure was 30 mPa.
  • a catalytic metal element-containing layer (5) composed of Pt having a layer thickness of 10 nm is formed on the tungsten oxide-containing layer (4) thus formed by sputtering similar to the above using platinum (Pt) as a target.
  • the hydrogen gas detection member 1 was produced by depositing.
  • Ar gas partial pressure was 170 mPa.
  • Hydrogen gas detection members 4 to 6 were prepared in the same manner as in the preparation of the hydrogen gas detection members 1 to 3, except that the cerium oxide-containing layer (3) was not formed.
  • the change in light transmittance (%) was measured using the hydrogen gas detection measuring device (50) shown in FIG. 5A.
  • each of the produced hydrogen gas detection members (1) was installed and fixed so that the light source part (51) side was the substrate (2) surface.
  • visible light (L) is irradiated from the light source part (51) while flowing air into the hydrogen gas detection measuring device (50) from the gas inlet (54) and out of the gas outlet (55).
  • the light transmittance TP1 (the ratio (%) of light transmitted light to the total irradiated light) in an air atmosphere with light having a wavelength of 600 nm was measured with a spectrophotometer (52).
  • Table 1 shows the results obtained as described above.
  • the hydrogen gas detection member provided with the cerium oxide-containing layer (3) under the tungsten oxide-containing layer (4) and in which the cerium oxide and tungsten oxide are in contact with each other, Compared to the comparative example, the color change when exposed to hydrogen gas, specifically, from pale yellow-green tungsten oxide (H x WO 3 ) to dark blue (tungsten bronze) tungsten oxide (H y WO 3 ). It can be seen that the decrease in the light transmittance in the visible light region due to the change of is large, and the detection sensitivity of hydrogen gas is high.
  • the hydrogen gas detection member 4 of the comparative example is 40%, whereas the hydrogen gas detection member 1 of the present invention is reduced to 19%.
  • the hydrogen gas detection member 5 is 39%, whereas the hydrogen gas detection member 2 is reduced to 21%.
  • the hydrogen gas detection member 6 is 65%.
  • the hydrogen gas detecting member 3 decreases to 37%, and it can be seen that the hydrogen gas detecting ability is greatly improved by providing the cerium oxide-containing layer in any catalyst system.
  • Example 2 Preparation of core / shell particle hydrogen gas detection member ⁇
  • hydrogen gas detecting members 11 to 15 of core / shell type particles were produced.
  • the mixed solution (106) of the cerium nitrate aqueous solution and the cerium nitrate aqueous solution from the preparation kettle (105) of step a1 is added to the aqueous ammonia solution in the reaction kettle (101) using an N 2 gas.
  • a suspension (104) was prepared by adding at an addition rate of 4 mL / min over 25 minutes while stirring under an atmosphere.
  • the suspension was heated to 80 ° C. while agitating and stirring N 2 gas, and this state was maintained for 3 hours.
  • a suspension (104) containing cerium oxide particles (core particles) was prepared.
  • the first shell layer is formed on the surface of the core particles composed of the cerium oxide prepared above.
  • the core-shell type particles were prepared by coating with tungstic acid.
  • the suspension (104) containing the cerium oxide particles (core particles) prepared above is stored as a mother liquor in the reaction kettle (111), and the tungstic acid is stirred from the preparation kettle (115) while stirring the suspension (104). Aqueous sodium solution (116) was added.
  • an aqueous nitric acid solution (116b) is added to the same suspension (104) from another series of preparation kettles (115b) over 25 minutes, and the pH is lowered to 1.0.
  • the suspension was subjected to washing treatment by repeating centrifugation, decantation of the supernatant liquid and addition of pure water five times.
  • H 2 PtCl 6 ⁇ from the preparation kettle (125) was added to the 5 mass% CeO 2 / H 2 WO 4 suspension (112) of the reaction kettle (121) using the liquid feed pump (128).
  • a 6H 2 O aqueous solution (126) was added with stirring over 30 minutes, and a catalytic metal element-containing layer containing platinum as a catalyst was supported on the H 2 WO 4 layer at a thickness of 2 nm.
  • CeO 2 / H 2 A suspension (127) containing core / shell particles of WO 4 / Pt was prepared by stirring for 5 hours.
  • the powder from which moisture was removed was dried at 100 ° C. for 3 hours, and then subjected to a firing treatment at 200 ° C. for 1 hour to obtain an average particle diameter of 112 nm composed of CeO 2 / H x WO 3 / Pt.
  • a hydrogen gas detection member 11 that is a core-shell type particle was prepared.
  • Example 3 Using the hydrogen gas container installation chamber (61) having the same configuration as described in FIG. 6, the hydrogen gas detection effect by the hydrogen gas detection member against hydrogen gas leakage was demonstrated.
  • a hydrogen gas cylinder (C) and a hydrogen gas tank (D) were arranged as a hydrogen gas source in a hydrogen gas container installation chamber (61) having the configuration shown in FIG.
  • the hydrogen gas detection member in the form of a thin film sheet produced in Example 1 was attached to the wall surface (B) of the test chamber, the surface of the hydrogen gas cylinder (C), and the surface of the hydrogen gas tank (D).
  • an optical measurement device (62) for measuring the hue change of the hydrogen gas detection member in the test chamber a detection device (63) for monitoring the hue change obtained by the optical measurement device (62), and the optical measurement device (62) an alarm device (64) that issues an alarm when the change in the hue of the hydrogen gas detection member due to the leakage of the hydrogen gas exceeds a predetermined threshold, and the occurrence of hydrogen gas leakage
  • a hydrogen gas detection system including a gas supply control unit (65) for transmitting a control signal (66) for shutting off a valve serving as a source and stopping driving of a pump was installed.
  • the hydrogen gas detection member of the present invention has high detection sensitivity to the hydrogen gas concentration, and leakage of hydrogen gas in the environment where the hydrogen gas is used, for example, in the production process, storage, transportation or consumption of the hydrogen gas. Can be used in advance as a highly sensitive hydrogen gas detection system for preventing disasters caused by hydrogen gas.

Abstract

The present invention addresses the problem of providing: a hydrogen gas detecting member exhibiting large variations in light transmittance or color according to hydrogen gas concentration and having a high detection sensitivity; a method for manufacturing the same; and a hydrogen gas detecting system having the same. The problem is solved by a hydrogen gas detecting member in which the light absorption characteristics vary with changes in hydrogen gas concentration, the hydrogen gas detecting member including a cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer, wherein the cerium oxide-containing layer is disposed adjacent to the tungsten oxide-containing layer, and the catalytic metal element-containing layer is disposed on the reverse side of the surface of the tungsten oxide-containing layer facing the cerium oxide-containing layer.

Description

水素ガス検知用部材とその製造方法及び水素ガス検知システムHydrogen gas detection member, manufacturing method thereof, and hydrogen gas detection system
　本発明は、水素ガス検知用部材とその製造方法及び水素ガス検知システムに関する。より詳しくは、水素ガス検知用ガスクロミック材料を用いた水素ガス検知用部材とその製造方法及び水素ガス検知システムに関する。 The present invention relates to a hydrogen gas detection member, a manufacturing method thereof, and a hydrogen gas detection system. More specifically, the present invention relates to a hydrogen gas detection member using a gas chromic material for hydrogen gas detection, a manufacturing method thereof, and a hydrogen gas detection system.
　近年、環境汚染問題や石油資源の枯渇問題に対する関心の高まりから、水素エネルギーが、次世代のエネルギーとして大きな注目を集めている。水素は、燃焼させても水が生成されるのみで、二酸化炭素や有害な硫化物、窒化物が排出されないクリーンなエネルギー源であり、また、水素ガスは、様々な方法で容易に製造することができる。そのため、近い将来、水素ガスが、重要なエネルギー源として、一般家庭、水素ガスステーションや工業用施設に供給されることが予想される。しかしながら、クリーンエネルギー源の水素は、酸素が存在する雰囲気中で爆発する危険性を持ち、例えば、空気中では水素ガス濃度が約４体積％（容量百分率）以上に達すると爆発する可能性があるとされている。したがって、その製造、貯蔵、輸送、あるいは消費の過程で、水素の燃焼・爆発による事故を未然に防ぐためには、水素ガスが供給される供給先や供給過程の経路において、水素ガスの漏えいを阻止することに加えて、水素ガスが雰囲気中に漏出した場合に、爆発する下限の濃度（爆発限界濃度）よりも低い濃度で、漏えいしている水素ガスを検知することが重要であり、このような観点から、水素ガス漏れ検知器及びこの検知器により水素ガスが検知された場合に、水素ガスの供給を停止させる水素ガス漏れ制御装置が必要とされている。 In recent years, hydrogen energy has attracted a great deal of attention as the next generation of energy due to growing interest in environmental pollution problems and oil resource depletion problems. Hydrogen is a clean energy source that does not emit carbon dioxide, harmful sulfides, and nitrides, and only produces water when burned. Hydrogen gas can be easily produced in various ways. Can do. Therefore, in the near future, hydrogen gas is expected to be supplied as an important energy source to ordinary households, hydrogen gas stations, and industrial facilities. However, hydrogen as a clean energy source has a risk of explosion in an atmosphere in which oxygen is present. For example, in the air, there is a possibility of explosion when the hydrogen gas concentration reaches about 4% by volume (volume percentage) or more. It is said that. Therefore, in order to prevent accidents caused by hydrogen combustion / explosion in the process of production, storage, transportation, or consumption, it is necessary to prevent leakage of hydrogen gas at the supply destination and route of the supply process. In addition, when hydrogen gas leaks into the atmosphere, it is important to detect leaking hydrogen gas at a concentration lower than the lower limit of explosion (explosion limit concentration). From this point of view, there is a need for a hydrogen gas leak detector and a hydrogen gas leak control device that stops the supply of hydrogen gas when hydrogen gas is detected by the detector.
　従来、水素ガスの検知に用いられる水素ガスセンサーとしては、半導体式センサー、固体電解質センサー、接触熱変換方式センサー、熱伝導式センサー、光検知式センサーなど点状センサーや、光学導波路や光ファイバのクラッドに光学的に水素検知を行う検知膜を有する面状センサーがあるが、水素を含むガス漏えい箇所の発見は困難である。例えば、酸化スズを用いた半導体センサーのような水素センサーは、元来、雰囲気中の水素濃度を定量的に測定するためのセンサーであり、水素ガスの漏えい個所を見つける用途には適しておらず、しかも、構造が複雑で、価格も高いという問題がある。 Conventionally, hydrogen gas sensors used for detecting hydrogen gas include semiconductor sensors, solid electrolyte sensors, contact heat conversion sensors, thermal conduction sensors, light detection sensors, point sensors, optical waveguides, and optical fibers. Although there is a planar sensor having a detection film for optically detecting hydrogen in the cladding of the metal, it is difficult to find a gas leaking portion containing hydrogen. For example, a hydrogen sensor such as a semiconductor sensor using tin oxide is originally a sensor for quantitatively measuring the hydrogen concentration in the atmosphere, and is not suitable for use in finding a leak point of hydrogen gas. Moreover, there is a problem that the structure is complicated and the price is high.
　また、特開２００４－５３５４０号公報には、マグネシウム薄膜の表面に触媒金属元素含有層が形成された水素センサー材料であって、水素と反応して電気抵抗又は光学的性質が変化することに基づいて水素を検知する水素センサー材料が開示されている。 Japanese Patent Application Laid-Open No. 2004-53540 discloses a hydrogen sensor material in which a catalytic metal element-containing layer is formed on the surface of a magnesium thin film, and is based on the fact that the electrical resistance or optical properties change by reacting with hydrogen. Hydrogen sensor materials that detect hydrogen are disclosed.
　しかし、この水素センサー材料を用いて水素を検知する場合も、例えば、電気抵抗を測定する場合は水素センサーの電気抵抗を測定する抵抗検出器や、抵抗検出器の検知結果に基づいて水素濃度を導出する演算処理装置が必要となり、光学的性質を測定する場合は、半導体レーザやフォトダイオードを用いた測定システムが必要となり、構造が複雑となる。 However, even when hydrogen is detected using this hydrogen sensor material, for example, when measuring electrical resistance, the hydrogen concentration is determined based on the resistance detector that measures the electrical resistance of the hydrogen sensor or the detection result of the resistance detector. An arithmetic processing device to be derived is required, and when measuring optical properties, a measurement system using a semiconductor laser or a photodiode is required, and the structure becomes complicated.
　現在、漏えいする微量の水素ガスを安全に検出する安価な水素センサーの開発が、水素社会を実現する上での最重要課題の一つとなっている。これまで実用化された水素センサーは、水素吸着による半導体表面の電気抵抗変化を検出手段として用いていたが、検出装置内に、爆発の着火源となりうる電源回路を伴うため安全性に問題があった。 Currently, the development of an inexpensive hydrogen sensor that can safely detect a small amount of leaking hydrogen gas is one of the most important issues in realizing a hydrogen society. Until now, hydrogen sensors put into practical use have used the electrical resistance change on the semiconductor surface due to hydrogen adsorption as a detection means, but there is a problem in safety because the detection device is accompanied by a power supply circuit that can be the ignition source of the explosion. there were.
　そこで安全性の高い水素センサーとして、水素ガス吸着により着色するガスクロミック特性を有する遷移金属酸化物（ＷＯ３、ＭｏＯ３、ＴｉＯ２など）を用いた光検出式水素センサーが、例えば、特公平３－６７２１８号公報に提案されている。表面に白金又はプラチナが触媒金属として堆積されている酸化タングステン（ＨｘＷＯ３）薄膜は、室温（２０℃付近）で水素を存在する雰囲気に触れると、着色してガスクロミック特性を発現する。酸化タングステン薄膜の水素吸着による着色率は、波長６３０ｎｍの可視光線（赤色光）に対して５０％以上である。したがって、酸化タングステン薄膜の水素吸着による光学的な透過率の変化を利用することにより、水素の検出が可能となり、酸化タングステン薄膜は、酸化スズの代替材料になると期待される。 Therefore, as a highly safe hydrogen sensor, a photodetection type hydrogen sensor using a transition metal oxide (WO 3 , MoO 3 , TiO 2, etc.) having a gas chromic property that is colored by hydrogen gas adsorption is, for example, -67218 is proposed. A tungsten oxide (HxWO 3 ) thin film having platinum or platinum deposited on its surface as a catalyst metal is colored and exhibits gaschromic properties when exposed to an atmosphere containing hydrogen at room temperature (around 20 ° C.). The coloring rate by hydrogen adsorption of the tungsten oxide thin film is 50% or more for visible light (red light) having a wavelength of 630 nm. Therefore, hydrogen can be detected by utilizing the change in optical transmittance due to hydrogen adsorption of the tungsten oxide thin film, and the tungsten oxide thin film is expected to be an alternative material for tin oxide.
　しかし、上記の酸化タングステン薄膜からなる水素検出材料は、空気中に長期間放置すると、触媒金属層表面に有機物等が付着することにより、水素検出性能が著しく低下する問題を抱えている。 However, the hydrogen detection material composed of the above-described tungsten oxide thin film has a problem in that the hydrogen detection performance is remarkably deteriorated due to adhesion of organic substances or the like to the surface of the catalyst metal layer when left in the air for a long period of time.
　上記問題に対し、水素ガス等の燃料ガスを扱う構造体（例えば、ガスタンク、ガス配管等）の表面に塗布され、漏えいする燃料ガスに接触すると変色する塗膜であって、顔料として金属酸化物粉体を、バインダーとしてアルコキシシランを、触媒として塩酸を、溶媒としてエチルアルコール、水及びイソプロピルアルコールを用いた燃料ガス漏えい検知塗膜が開示されている（例えば、特許文献１参照。）。 In order to solve the above problems, the coating is applied to the surface of a structure (for example, a gas tank, a gas pipe, etc.) that handles a fuel gas such as hydrogen gas, and changes its color when it comes into contact with the leaking fuel gas. A fuel gas leak detection coating film using powder, alkoxysilane as a binder, hydrochloric acid as a catalyst, and ethyl alcohol, water and isopropyl alcohol as a solvent is disclosed (for example, see Patent Document 1).
　しかしながら、特許文献１に記載されている方法は、常温近傍における環境では、水素ガスの漏えいに対する検出感度が低く、かつ水素ガスの検出に対する応答速度が非常に遅く、実用化に対しては問題を抱えている。 However, the method described in Patent Document 1 has a low detection sensitivity for leakage of hydrogen gas and an extremely slow response speed for detection of hydrogen gas in an environment near room temperature, which causes a problem for practical use. I have it.
　上記のような水素ガスに対する検出感度及び応答速度を向上させる方法として、ガス配管等の表面に塗設して、水素ガスを解離し、生成されるプロトンを注入して還元されることにより、色相が変化する水素ガス検知用塗膜顔料が知られている。当該顔料は、酸化タングステンを主成分とする結晶微粒子の集合体で構成され、前記結晶微粒子酸化タングステンの表面に酸化状態の触媒金属を含有する水素ガス検知用塗膜顔料とそれを適用した水素ガス検知テープが開示されている（例えば、特許文献２参照。）。 As a method for improving the detection sensitivity and response speed for hydrogen gas as described above, it is applied to the surface of a gas pipe, etc., dissociated hydrogen gas, injected with protons to be reduced, and reduced in hue. A coating film pigment for hydrogen gas detection in which the temperature changes is known. The pigment is composed of an aggregate of crystalline fine particles mainly composed of tungsten oxide, and a coating film pigment for detecting hydrogen gas containing a catalytic metal in an oxidized state on the surface of the crystalline fine particle tungsten oxide and a hydrogen gas applied with the same. A detection tape is disclosed (for example, refer to Patent Document 2).
　しかしながら、特許文献２に記載されている方法でも、実用化という点では、水素ガスの漏えいに対する検出感度が未だ不十分であり、より高い検出感度を有する水素ガス検知システムの開発が切望されている。 However, even in the method described in Patent Document 2, detection sensitivity to leakage of hydrogen gas is still insufficient in terms of practical use, and development of a hydrogen gas detection system having higher detection sensitivity is eagerly desired. .
特開２０００－０４４８４０号公報JP 2000-044840 A 特開２００５－３４５３３８号公報JP 2005-345338 A
　本発明は、上記問題に鑑みてなされたものであり、その解決課題は、水素ガス濃度に対する光透過率変化や色相変化が大きく、高い検出感度を有する水素ガス検知用部材とその製造方法及びそれを具備した水素ガス検知システムを提供することである。 The present invention has been made in view of the above-mentioned problems, and a solution to the problem is a hydrogen gas detection member having a large change in light transmittance and hue with respect to the hydrogen gas concentration, a high detection sensitivity, and a method for manufacturing the same. It is providing the hydrogen gas detection system which equipped.
　本発明者は、上記課題に鑑み鋭意検討を進めた結果、酸化セリウム含有層、酸化タングステン含有層、及び触媒金属元素含有層を備え、前記酸化セリウム含有層と前記酸化タングステン含有層とが隣接して配置され、前記触媒金属元素含有層が、前記酸化タングステン含有層の、前記酸化セリウム含有層に対向する面とは反対側に配置され、水素ガス濃度変化に応じて、光吸収特性が変化する水素ガス検知用部材により、水素ガス濃度に対する光透過率変化や色相変化が大きく、高い検出感度を有する水素ガス検知用部材を提供することができることを見出し、本発明に至った。 As a result of intensive studies in view of the above problems, the inventor has a cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer, and the cerium oxide-containing layer and the tungsten oxide-containing layer are adjacent to each other. The catalytic metal element-containing layer is disposed on the opposite side of the tungsten oxide-containing layer from the surface facing the cerium oxide-containing layer, and the light absorption characteristics change according to the change in hydrogen gas concentration. It has been found that the hydrogen gas detection member can provide a hydrogen gas detection member having a high detection sensitivity with a large change in light transmittance and hue with respect to the hydrogen gas concentration.
　すなわち、本発明の上記課題は、下記の手段により解決される。 That is, the above-mentioned problem of the present invention is solved by the following means.
　１．酸化セリウム含有層、酸化タングステン含有層、及び触媒金属元素含有層を備え、
　前記酸化セリウム含有層と前記酸化タングステン含有層とが隣接して配置され、前記触媒金属元素含有層が、前記酸化タングステン含有層の、前記酸化セリウム含有層に対向する面とは反対側に配置され、
　水素ガス濃度変化に応じて、光吸収特性が変化することを特徴とする水素ガス検知用部材。 1. A cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer;
The cerium oxide-containing layer and the tungsten oxide-containing layer are disposed adjacent to each other, and the catalytic metal element-containing layer is disposed on the opposite side of the surface of the tungsten oxide-containing layer that faces the cerium oxide-containing layer. ,
A member for detecting hydrogen gas, wherein light absorption characteristics change according to a change in hydrogen gas concentration.
　２．前記触媒金属元素含有層が、白金、パラジウム、ロジウム、イリジウム、ルテニウム、オスミウム、コバルト、ニッケル及び銅から選ばれる金属元素を含有することを特徴とする第１項に記載の水素ガス検知用部材。 2. 2. The member for detecting hydrogen gas according to claim 1, wherein the catalytic metal element-containing layer contains a metal element selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, cobalt, nickel and copper.
　３．前記触媒金属元素含有層が、白金、パラジウム、コバルト、ニッケル、又は銅を含有することを特徴とする第１項又は第２項に記載の水素ガス検知用部材。 3. 3. The hydrogen gas detecting member according to claim 1 or 2, wherein the catalyst metal element-containing layer contains platinum, palladium, cobalt, nickel, or copper.
　４．前記酸化セリウム含有層、酸化タングステン含有層、及び触媒金属元素含有層より構成される水素ガス検知用部材が、薄膜シート状であることを特徴とする第１項から第３項までのいずれか一項に記載の水素ガス検知用部材。 4. The hydrogen gas detection member composed of the cerium oxide-containing layer, the tungsten oxide-containing layer, and the catalytic metal element-containing layer is in the form of a thin film sheet, any one of items 1 to 3 The hydrogen gas detection member according to item.
　５．前記酸化セリウム含有層、酸化タングステン含有層、及び触媒金属元素含有層より構成される水素ガス検知用部材が粒子状であり、前記触媒金属元素含有層が前記酸化タングステン含有層より外側にあることを特徴とする第１項から第３項までのいずれか一項に記載の水素ガス検知用部材。 5. The hydrogen gas detection member composed of the cerium oxide-containing layer, the tungsten oxide-containing layer, and the catalytic metal element-containing layer is in the form of particles, and the catalytic metal element-containing layer is outside the tungsten oxide-containing layer. The hydrogen gas detection member according to any one of Items 1 to 3, which is a feature.
　６．前記粒子状の水素ガス検知用部材が、３層よりなるコア・シェル構造を有し、コア部が酸化セリウム含有層で構成され、シェル部が酸化タングステン含有層及び触媒金属元素含有層で構成され、前記酸化セリウム含有層と前記酸化タングステン含有層とが接触している構造を有していることを特徴とする第５項に記載の水素ガス検知用部材。 6. The particulate hydrogen gas detection member has a core-shell structure consisting of three layers, the core part is composed of a cerium oxide-containing layer, and the shell part is composed of a tungsten oxide-containing layer and a catalytic metal element-containing layer. 6. The hydrogen gas detection member according to claim 5, wherein the cerium oxide-containing layer and the tungsten oxide-containing layer are in contact with each other.
　７．第１項から第４項までのいずれか一項に記載の水素ガス検知用部材を製造する水素ガス検知用部材の製造方法であって、
　酸化セリウム含有層と酸化タングステン含有層とを隣接して配置し、
　前記酸化タングステン含有層の、前記酸化セリウム含有層に対向する面とは反対側に、触媒金属元素含有層を配置する、
　ことを特徴とする水素ガス検知用部材の製造方法。 7). A method for producing a hydrogen gas detection member for producing the hydrogen gas detection member according to any one of items 1 to 4,
A cerium oxide-containing layer and a tungsten oxide-containing layer are disposed adjacent to each other;
Disposing a catalytic metal element-containing layer on the opposite side of the tungsten oxide-containing layer from the surface facing the cerium oxide-containing layer;
A method for producing a hydrogen gas detection member.
　８．第５項又は第６項に記載の水素ガス検知用部材を製造する水素ガス検知用部材の製造方法であって、
　酸化セリウムを含有するコア粒子を形成し、
　前記コア粒子上に、酸化タングステンを含有する第１のシェル部を形成し、
　前記第１のシェル部上に触媒金属元素を含む第２のシェル部を形成する、
　ことを特徴とする水素ガス検知用部材の製造方法。 8). A method for producing a hydrogen gas detection member for producing the hydrogen gas detection member according to item 5 or 6,
Forming core particles containing cerium oxide,
Forming a first shell portion containing tungsten oxide on the core particles;
Forming a second shell portion containing a catalytic metal element on the first shell portion;
A method for producing a hydrogen gas detection member.
　９．第１項から第６項までのいずれか一項に記載の水素ガス検知用部材と、
　当該水素ガス検知用部材に特定の波長を照射する光源部と、
　前記水素ガス検知用部材を通過した光を測定する光学測定装置と、
　前記光学測定装置で測定した光吸収特性が規定値を超えるか否かを検知する検知装置と、
　前記検知装置が検知する情報に基づき警報を発する警報装置と、
　を備えることを特徴とする水素ガス検知システム。 9. The hydrogen gas detection member according to any one of items 1 to 6,
A light source unit for irradiating the hydrogen gas detection member with a specific wavelength;
An optical measuring device for measuring the light passing through the hydrogen gas detecting member;
A detection device for detecting whether or not the light absorption characteristic measured by the optical measurement device exceeds a specified value;
An alarm device that issues an alarm based on information detected by the detection device; and
A hydrogen gas detection system comprising:
　１０．前記検知装置の検出する情報に基づき、水素ガスの供給を遮断するガス供給制御部をさらに備えることを特徴とする第９項に記載の水素ガス検知システム。 10. The hydrogen gas detection system according to claim 9, further comprising a gas supply control unit that blocks supply of hydrogen gas based on information detected by the detection device.
　本発明の上記構成を採用することにより、水素ガス濃度に対する光透過率変化や色相変化が大きく、高い検出感度を有する水素ガス検知用部材とその製造方法及びそれを具備した水素ガス検知システムを提供することができる。 By adopting the above-described configuration of the present invention, a hydrogen gas detection member having a large light transmittance change and hue change with respect to the hydrogen gas concentration and having a high detection sensitivity, a manufacturing method thereof, and a hydrogen gas detection system including the same are provided. can do.
　なお、上記効果の発現機構・作用機構は、明確にはなっていないが、以下のように推察される。 In addition, although the expression mechanism and action mechanism of the above effects are not clear, it is assumed as follows.
　酸化セリウム含有層、酸化タングステン含有層と触媒金属元素含有層で構成される部材で、酸化タングステン含有層と、酸化セリウム含有層とが互いに隣接した配置とすることにより、水素ガスが、触媒（例えば、パラジウム、白金等）により、プロトンと電子に分解した後、酸化タングステン（ＨｘＷＯ３、ｘは０．５以上、０．８未満。）を含む層に侵入して、無色～淡黄色の酸化タングステン（ＨｘＷＯ３）が、青色の酸化タングステン（ＨｙＷＯ３、ｙは０．８以上、１．０以下。）に変換することにより、色相や光透過率の変化を生じることになる。この時、プロトンの侵入により酸化タングステンの結晶構造が変化していると考えられるが、酸素吸引性を有する酸化セリウムを、酸化タングステンとの結晶粒界に存在させることにより、酸化タングステンの酸素原子が、セリウムに強くひきつけられ、酸化タングステンの結晶構造が不安定なものとなり、層表面より侵入してくる水素がトリガーとなって、酸化タングステンの結晶構造が速やかな変化を発現することにより、水素ガス濃度に対する光透過率変化や色相変化が大きくなり、検出感度を飛躍的に高めることができると推測される。 A member composed of a cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer, wherein the tungsten oxide-containing layer and the cerium oxide-containing layer are arranged adjacent to each other, so that hydrogen gas is converted into a catalyst (for example, , Palladium, platinum, etc.) to decompose into protons and electrons, and then enter a layer containing tungsten oxide (H x WO 3 , where x is 0.5 or more and less than 0.8) to form colorless to pale yellow Tungsten oxide (H x WO 3 ) is converted into blue tungsten oxide (H y WO 3 , y is 0.8 or more and 1.0 or less), thereby causing a change in hue or light transmittance. Become. At this time, it is considered that the crystal structure of tungsten oxide has changed due to the invasion of protons. However, the presence of oxygen-attracting cerium oxide at the crystal grain boundary with tungsten oxide allows the oxygen atoms of tungsten oxide to be changed. Hydrogen gas is attracted strongly to cerium, the crystal structure of tungsten oxide becomes unstable, and hydrogen entering from the surface of the layer serves as a trigger, and the crystal structure of tungsten oxide rapidly changes. It is estimated that the light transmittance change and the hue change with respect to the density increase, and the detection sensitivity can be dramatically increased.
　また、本発明の水素ガス検知用部材を含む塗布液を準備し、水素ガスを含むタンク、ボンベ、使用機器、ポンプ、バルブ、配管、あるいは保管容器に塗布して水素ガス検知用塗膜を形成することにより、水素ガス漏えい時に、当該水素ガス検知用塗膜の光吸収スペクトル（光吸収特性）が大きく変化するため、目視あるいは光学的な検視手段(例えば、カメラ、分光光度計等)で水素ガスの速やかに検知し、水素ガス漏えいに対し、迅速な処置を取りことができる。 In addition, a coating liquid containing the hydrogen gas detection member of the present invention is prepared and applied to a tank, cylinder, equipment used, pump, valve, piping, or storage container containing hydrogen gas to form a hydrogen gas detection coating film. As a result, when the hydrogen gas leaks, the light absorption spectrum (light absorption characteristics) of the coating film for hydrogen gas detection changes greatly. Therefore, hydrogen can be detected visually or by optical inspection means (eg, camera, spectrophotometer, etc.). It can detect gas quickly and take quick measures against hydrogen gas leakage.
水素ガス検知用部材の構成の一例を示す概略断面図Schematic sectional view showing an example of the configuration of the hydrogen gas detection member 水素ガス検知用部材の構成の他の一例を示す概略断面図Schematic sectional view showing another example of the configuration of the hydrogen gas detection member 水素ガス検知用部材の構成の他の一例を示す概略断面図Schematic sectional view showing another example of the configuration of the hydrogen gas detection member コア・シェル型の水素ガス検知用粒子の製造フローの一例を示す図Diagram showing an example of the production flow of core / shell type hydrogen gas detection particles コア・シェル型の水素ガス検知用粒子の製造工程の一例を示す図The figure which shows an example of the manufacturing process of the particle for hydrogen gas detection of a core shell type 水素ガス検知システム（光透過型）の基本構成の一例を示す概略図Schematic showing an example of the basic configuration of the hydrogen gas detection system (light transmission type) 水素ガス検知システム（反射型）の基本構成の一例を示す概略図Schematic showing an example of the basic configuration of the hydrogen gas detection system (reflection type) 水素ガス検知用部材を用いた水素ガス検知システムの一例を示す概略図Schematic showing an example of a hydrogen gas detection system using a hydrogen gas detection member
　以下、本発明の実施形態について説明する。なお、以下の説明において示す「～」は、その前後に記載される数値を下限値及び上限値として含む意味で使用する。 Hereinafter, embodiments of the present invention will be described. In the following description, “˜” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
　《水素ガス検知用部材の概要と基本構成》
　本実施形態の水素ガス検知用部材は、酸化セリウム含有層、酸化タングステン含有層、及び触媒金属元素含有層を備え、前記酸化セリウム含有層と前記酸化タングステン含有層が隣接して配置され、前記触媒金属元素含有層が、前記酸化タングステン含有層の、前記酸化セリウム含有層に対向する面とは反対側に配置され、水素ガス濃度変化に応じて、光吸収特性が変化することを特徴とする。 <Outline and basic configuration of hydrogen gas detection components>
The hydrogen gas detection member of the present embodiment includes a cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer, wherein the cerium oxide-containing layer and the tungsten oxide-containing layer are disposed adjacent to each other, and the catalyst The metal element-containing layer is disposed on the opposite side of the tungsten oxide-containing layer from the surface facing the cerium oxide-containing layer, and the light absorption characteristic changes according to a change in hydrogen gas concentration.
　一般に、水素に反応するガスクロミック材料を用いた水素ガス検知方式としては、大別して、
　１）水素化触媒と金属酸化物との組み合わせで、水素ガスと反応した際に、金属酸化物の透過率の変化や色の濃淡を検知する方法、
　２）水素化触媒と金属合金との組み合わせで、水素ガスと反応した際に、金属合金の透過率の変化により検知する方法、
　３）水素化触媒と有機色素との組み合わせで、水素ガスと反応した際に、有機色素の吸収波長のシフト（色相の変化）により検知する方法、
　等が挙げられるが、本実施形態の水素ガス検知用部材は、上記１）項に記載の水素化触媒と金属酸化物とを組み合わせた方法である。 In general, hydrogen gas detection methods using gas chromic materials that react with hydrogen are roughly classified as follows:
1) A combination of a hydrogenation catalyst and a metal oxide, and a method of detecting a change in the transmittance of the metal oxide and color shading when reacting with hydrogen gas,
2) A combination of a hydrogenation catalyst and a metal alloy, and a method for detecting by a change in the transmittance of the metal alloy when reacting with hydrogen gas,
3) A combination of a hydrogenation catalyst and an organic dye, and a method of detecting by a shift in the absorption wavelength of the organic dye (change in hue) when reacting with hydrogen gas,
However, the hydrogen gas detection member of this embodiment is a method in which the hydrogenation catalyst described in the above item 1) is combined with a metal oxide.
　上記１）項において、触媒金属と、金属酸化物として酸化タングステン（ＨｘＷＯ３）により構成する水素ガス検知用部材を用いた水素ガス検知方式では、水素ガス検知用部材の表面に水素ガスが接触されると、触媒金属により水素ガスを構成する水素原子からプロトン（Ｈ＋）および電子（ｅ－）が生成され、このプロトン（Ｈ＋）および電子（ｅ－）が触媒金属によるスピルオーバー効果によって、その下部に配置されている酸化タングステン含有層中に供給され、酸化タングステンが、通常状態である６価の状態から、プロトン（Ｈ＋）が挿入された、いわゆるタングステンブロンズ構造と呼ばれる５価の状態に変化する。 In the above item 1), in the hydrogen gas detection system using the hydrogen gas detection member composed of the catalyst metal and tungsten oxide (H x WO 3 ) as the metal oxide, hydrogen gas is present on the surface of the hydrogen gas detection member. When contacted, the catalyst metal generates protons (H + ) and electrons (e − ) from the hydrogen atoms constituting the hydrogen gas, and these protons (H + ) and electrons (e − ) are caused by the spillover effect of the catalyst metal. The tungsten oxide is supplied into a tungsten oxide-containing layer disposed therebelow, and the tungsten oxide has a pentavalent structure called a so-called tungsten bronze structure in which protons (H + ) are inserted from a normal hexavalent state. Change to state.
　この６価の状態と５価の状態との間を遷移する電子による原子価間移動吸収によって、水素ガス検知用部材が、波長域６００～８００ｎｍの可視光が吸収される特定の低い光透過率を有する呈色状態に変化する。このとき、通常状態においては無色透明であった酸化タングステン含有層は、青色（タングステンブロンズ）を呈する状態となる。 The hydrogen gas detecting member absorbs visible light in the wavelength range of 600 to 800 nm by the intervalence transfer absorption by the electrons transitioning between the hexavalent state and the pentavalent state. It changes to the coloring state which has. At this time, the tungsten oxide-containing layer, which is colorless and transparent in the normal state, is in a state of exhibiting blue (tungsten bronze).
　一方、水素ガスの導入が停止されて、例えば、水素ガス検知用部材が大気に曝されると、酸化タングステン含有層において、タングステンブロンズ構造の５価の三酸化タングステンからプロトン（Ｈ+ ）が脱離されることによって、呈色状態から通常状態に復帰し、酸化タングステン含有層は、青色から無色透明な状態に回復する。 On the other hand, when the introduction of hydrogen gas is stopped, for example, when the hydrogen gas detection member is exposed to the atmosphere, protons (H + ) are desorbed from the tungsten bronze-structured pentavalent tungsten trioxide in the tungsten oxide-containing layer. When released, the color state returns to the normal state, and the tungsten oxide-containing layer recovers from blue to a colorless and transparent state.
　上記のようなメカニズムで、ガスクロミック特性を発現する水素ガス検知用部材において、酸化タングステン含有層に隣接した下部に、酸化セリウム含有層を配置することにより、水素ガス導入時に、酸化タングステンの酸素原子が、隣接する層に存在するセリウム原子にひきつけられやすくなり、構造が不安定化し、容易に、結晶構造として、無色の酸化タングステン（ＨｘＷＯ３）から青色の酸化タングステン（ＨｙＷＯ３）に変化しやすくなり、水素ガスの検知感度が大幅に上昇したものと推測している。ここで、ｘは０．５以上、０．８未満の範囲内の数値であり、ｙは０．８以上、１．０以下の数値の範囲内である。 In the hydrogen gas detection member that exhibits gaschromic characteristics by the mechanism as described above, by arranging the cerium oxide-containing layer in the lower part adjacent to the tungsten oxide-containing layer, oxygen atoms of tungsten oxide are introduced when hydrogen gas is introduced. Is easily attracted to cerium atoms existing in adjacent layers, the structure becomes unstable, and easily changes from a colorless tungsten oxide (H x WO 3 ) to a blue tungsten oxide (H y WO 3 ) as a crystal structure. It is assumed that the hydrogen gas detection sensitivity has greatly increased. Here, x is a numerical value within a range of 0.5 or more and less than 0.8, and y is within a numerical value range of 0.8 or more and 1.0 or less.
　本実施形態の水素ガス検知用部材は、酸化セリウム含有層、酸化タングステン含有層、及び触媒金属元素含有層を含み、前記酸化セリウム含有層と前記酸化タングステン含有層とが隣接して配置され、前記触媒金属元素含有層が、前記酸化タングステン含有層の、前記酸化セリウム含有層に対向する面とは反対側に配置されていることを特徴とする。更に、水素ガス検知用部材の好ましい形態は、粒子状又は薄膜シート状の部材である。 The hydrogen gas detection member of the present embodiment includes a cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer, and the cerium oxide-containing layer and the tungsten oxide-containing layer are disposed adjacent to each other, The catalytic metal element-containing layer is disposed on the opposite side of the tungsten oxide-containing layer from the surface facing the cerium oxide-containing layer. Furthermore, the preferable form of the member for hydrogen gas detection is a member of a particle form or a thin film sheet form.
　図１Ａ及び図１Ｂは、薄膜シート状の従来型の水素ガス検知用部材と、本実施形態の水素ガス検知用部材の構成の一例を示す概略断面図である。 FIG. 1A and FIG. 1B are schematic sectional views showing an example of the configuration of a conventional hydrogen gas detection member in the form of a thin film sheet and the hydrogen gas detection member of the present embodiment.
　図１Ａに示す薄膜シート状の水素ガス検知用部材（１Ａ）は、従来型の水素ガス検知用部材であり、基板（２）上に、水素ガスを検知する酸化タングステン含有層（４）と触媒金属元素含有層（５）が積層されている構成であるが、このような構成の水素ガス検知用部材では、漏えいした水素ガス濃度に対する検知感度が低いという問題があった。 A thin-film sheet-like hydrogen gas detection member (1A) shown in FIG. 1A is a conventional hydrogen gas detection member, and a tungsten oxide-containing layer (4) for detecting hydrogen gas and a catalyst on a substrate (2). Although the metal element-containing layer (5) is configured to be laminated, the hydrogen gas detection member having such a configuration has a problem that the detection sensitivity with respect to the leaked hydrogen gas concentration is low.
　これに対し、図１Ｂに示す薄膜シート状の水素ガス検知用部材（１Ｂ）は、基板（２）上に、酸化タングステン含有層（４）のガスクロミック効果を増大させ、検知感度を高めることを目的として酸化セリウム含有層（３）が配置され、その上に、水素ガスを検知する酸化タングステン含有層（４）と触媒金属元素含有層（５）が積層されている構成である。このような酸化セリウム含有層（３）を設ける構成の水素ガス検知用部材（１Ｂ）とすることにより、水素ガスを検知した際の酸化タングステン含有層（４）において、ＨｘＷＯ３（淡黄色）からＨｙＷＯ３（青色）への色相変化速度を増大させることができ、その結果、水素ガス濃度に対する検知感度を高めることができる。本実施形態の水素ガス検知用部材（１Ｂ）においては、上記のような効果を発現させるためには、酸化セリウム含有層（３）と酸化タングステン含有層（４）が隣接し、結晶粒界（Ｇｂ）を形成していることが特徴である。 On the other hand, the thin-film sheet-shaped hydrogen gas detection member (1B) shown in FIG. 1B increases the gaschromic effect of the tungsten oxide-containing layer (4) on the substrate (2), thereby increasing the detection sensitivity. For the purpose, a cerium oxide-containing layer (3) is disposed, and a tungsten oxide-containing layer (4) for detecting hydrogen gas and a catalytic metal element-containing layer (5) are laminated thereon. By using the hydrogen gas detecting member (1B) configured to provide such a cerium oxide-containing layer (3), in the tungsten oxide-containing layer (4) when hydrogen gas is detected, H x WO 3 (light yellow ) To H y WO 3 (blue) can be increased, and as a result, the detection sensitivity to the hydrogen gas concentration can be increased. In the hydrogen gas detection member (1B) of the present embodiment, in order to exhibit the above effects, the cerium oxide-containing layer (3) and the tungsten oxide-containing layer (4) are adjacent to each other, and the crystal grain boundary ( It is characteristic that Gb) is formed.
　図２は、水素ガス検知用部材の構成の他の一例で、コア・シェル構造を有する粒子状の水素ガス検知用部材の概略断面図である。 FIG. 2 is a schematic cross-sectional view of a particulate hydrogen gas detection member having a core-shell structure as another example of the configuration of the hydrogen gas detection member.
　図２に示す水素ガス検知用部材（１Ｐ）では、コア部に酸化セリウム含有層（３）を形成し、その表面部に、第１のシェル部として、酸化タングステン含有層（４）を被覆し、更にその表面部に、換言すれば酸化タングステン含有層（４）よりも外側に、第２のシェル部として、触媒金属元素含有層（５）を担持させて、コア・シェル型構造の粒子を構成する。 In the hydrogen gas detection member (1P) shown in FIG. 2, a cerium oxide-containing layer (3) is formed on the core portion, and a tungsten oxide-containing layer (4) is coated on the surface portion as a first shell portion. Further, the catalyst-metal element-containing layer (5) is supported as a second shell portion on the surface portion, in other words, outside the tungsten oxide-containing layer (4), and particles having a core-shell type structure are supported. Constitute.
　図２に示すコア・シェル構造を有する粒子を含む水素ガス検知用部材（１Ｐ）においても、酸化セリウム含有層（３）と酸化タングステン含有層（４）とが隣接して配置され、結晶粒界（Ｇｂ）を形成していることが重要である。 Also in the hydrogen gas detection member (1P) including particles having a core-shell structure shown in FIG. 2, the cerium oxide-containing layer (3) and the tungsten oxide-containing layer (4) are disposed adjacent to each other, and the grain boundary It is important to form (Gb).
　《水素ガス検知用部材の構成要素及び水素ガス検知用部材の製造方法》
　水素ガス検知用部材の形態としては、特に制限はないが、上記図１Ｂで示したような薄膜シート状の水素ガス検知用部材、あるいは、図２で示したようなコア・シェル型構造を有する粒子状であることが好ましい。また、水素ガス検知用部材の製造方法は、以下に説明するように、酸化セリウム含有層と酸化タングステン層とを隣接して配置する工程と、酸化タングステン含有層の、酸化セリウム含有層に対向する面とは反対側に、触媒金属元素含有層（５）を配置する工程とを含んでいる。 << Components of Hydrogen Gas Detection Member and Manufacturing Method of Hydrogen Gas Detection Member >>
Although there is no restriction | limiting in particular as a form of the member for hydrogen gas detection, It has a thin film sheet-like hydrogen gas detection member as shown in the said FIG. 1B, or a core-shell type structure as shown in FIG. It is preferably in the form of particles. Moreover, the manufacturing method of the member for hydrogen gas detection faces the cerium oxide containing layer of the process of arrange | positioning a cerium oxide containing layer and a tungsten oxide layer adjacently, and a tungsten oxide containing layer so that it may demonstrate below. And a step of disposing the catalytic metal element-containing layer (5) on the side opposite to the surface.
　以下、代表例として、薄膜シート状及びコア・シェル型構造を有する粒子状の水素ガス検知用部材について、その詳細を説明する。 Hereinafter, as a representative example, the details of the particulate hydrogen gas detection member having a thin film sheet shape and a core / shell structure will be described.
　［薄膜シート状の水素ガス検知用部材］
　薄膜シート状の水素ガス検知用部材（１Ｂ）は、図１Ｂで示すように、基板（２）上に、酸化セリウム含有層（３）、水素ガスを検知する酸化タングステン含有層（４）、及び触媒金属元素含有層（５）が、この順で積層された構成である。 [Thin-sheet hydrogen gas detection member]
As shown in FIG. 1B, the thin-film sheet-like hydrogen gas detection member (1B) has, on the substrate (2), a cerium oxide-containing layer (3), a tungsten oxide-containing layer (4) for detecting hydrogen gas, and The catalyst metal element-containing layer (5) is laminated in this order.
　〔基板〕
　薄膜シート状の水素ガス検知用部材（１Ｂ）に適用可能な基板（２）としては、特に制限はないが、上面に形成する酸化セリウム含有層（３）、酸化タングステン含有層（４）及び触媒金属元素含有層（５）を形成する環境、例えば、各層形成時の製造条件（温度等）に対する耐久性を有している基板であることが望ましい。 〔substrate〕
Although there is no restriction | limiting in particular as a board | substrate (2) applicable to the member (1B) for hydrogen gas detection of a thin film sheet form, The cerium oxide containing layer (3), tungsten oxide containing layer (4), and catalyst which are formed in the upper surface It is desirable that the substrate has durability against the environment in which the metal element-containing layer (5) is formed, for example, the manufacturing conditions (temperature, etc.) at the time of forming each layer.
　このような条件に対し好適な基板としては、例えば、ポリエステル（例えば、ポリエチレンテレフタレート等）、ポリイミド、ポリメタクリル酸メチル、ポリスチレン、ポリプロピレン、ポリエチレン、ポリアミド、ナイロン、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリカーボネート、ポリエーテルスルフォン、シリコン樹脂、ポリアセタール樹脂、フッ素樹脂、セルロース誘導体、ポリオレフィン等の高分子のフィルムや板状基板、石英ガラス等のガラス基板などが好ましく用いられる。 Suitable substrates for such conditions include, for example, polyester (for example, polyethylene terephthalate), polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, polyamide, nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, Polyether sulfone, silicon resin, polyacetal resin, fluororesin, cellulose derivatives, polymer films such as polyolefin, plate substrates, glass substrates such as quartz glass, and the like are preferably used.
　〔酸化セリウム含有層、酸化タングステン含有層及び触媒金属元素含有層の形成方法〕
　本実施態様の水素ガス検知用部材において、酸化セリウム含有層（３）と酸化タングステン含有層（４）の厚さとしては、それぞれ２５～５００ｎｍの範囲内の薄膜であることが好ましい。特に、酸化タングステン含有層（４）の厚さが２５ｎｍ以上であれば、水素ガスに接触した際の透過率の変化や色相の変化を確実に検知することができる。また、それぞれの厚さが５００ｎｍ以下であれば、酸化セリウム含有層（３）及び酸化タングステン含有層（４）の層間剥離の発生を防止することができる。 [Method of forming cerium oxide-containing layer, tungsten oxide-containing layer and catalytic metal element-containing layer]
In the hydrogen gas detection member of this embodiment, the cerium oxide-containing layer (3) and the tungsten oxide-containing layer (4) are each preferably a thin film having a thickness in the range of 25 to 500 nm. In particular, when the thickness of the tungsten oxide-containing layer (4) is 25 nm or more, it is possible to reliably detect a change in transmittance and a change in hue when in contact with hydrogen gas. Moreover, if each thickness is 500 nm or less, generation | occurrence | production of the delamination of a cerium oxide content layer (3) and a tungsten oxide content layer (4) can be prevented.
　また、堆積させる触媒金属元素含有層（５）の厚さは１～２０ｎｍの範囲内であることが好ましい。触媒金属元素含有層（５）の厚さが２０ｎｍ以下であれば、触媒自身による入射光の遮蔽を抑制することができ、透過光強度の変化の判別を阻害することがない。また、触媒金属元素含有層（５）の厚さが１ｎｍ以上であれば、目視により容易に判別が可能な透過光強度の変化が得られ、水素ガスの検知が可能となる。 The thickness of the catalyst metal element-containing layer (5) to be deposited is preferably in the range of 1 to 20 nm. If the thickness of the catalytic metal element-containing layer (5) is 20 nm or less, the shielding of incident light by the catalyst itself can be suppressed, and discrimination of changes in transmitted light intensity is not hindered. Moreover, if the thickness of the catalyst metal element-containing layer (5) is 1 nm or more, a change in transmitted light intensity that can be easily discriminated by visual observation can be obtained, and hydrogen gas can be detected.
　水素ガス検知用部材（１Ｂ）において、酸化セリウム含有層（３）、及び酸化タングステン含有層（４）の形成方法としては、特に制限はなく、実施例は、スパッタリング法を用いたが、高周波スパッタリング法、直流スパッタリング法、真空蒸着法、電子ビーム蒸着法、化学気相蒸着法、パルスレーザーデポジション法（ＰＬＤ法）、めっき法、ゾルゲル法等を、適宜選択して適用することができる。 In the hydrogen gas detecting member (1B), the method for forming the cerium oxide-containing layer (3) and the tungsten oxide-containing layer (4) is not particularly limited, and the sputtering method is used in the examples. Methods, DC sputtering methods, vacuum deposition methods, electron beam deposition methods, chemical vapor deposition methods, pulsed laser deposition methods (PLD methods), plating methods, sol-gel methods, and the like can be appropriately selected and applied.
　例えば、酸化セリウム含有層（３）、酸化タングステン含有層（４）及び触媒金属元素含有層（５）の形成をスパッタリング法で行う場合には、酸化セリウム、タングステン、触媒金属をそれぞれスパッタリングターゲットとしてスパッタリングして、基板の表面上に、酸化セリウム薄膜、酸化タングステン薄膜を形成し、次いで、酸化タングステン薄膜の表面上に触媒金属を堆積することにより形成することができる。 For example, when the cerium oxide-containing layer (3), the tungsten oxide-containing layer (4), and the catalytic metal element-containing layer (5) are formed by sputtering, sputtering is performed using cerium oxide, tungsten, and catalytic metal as sputtering targets, respectively. Then, a cerium oxide thin film and a tungsten oxide thin film are formed on the surface of the substrate, and then a catalytic metal is deposited on the surface of the tungsten oxide thin film.
　スパッタリングは、アルゴンと酸素の混合雰囲気であることが好ましい。スパッタリングを行う際の基板温度は、好ましくは室温（２０℃）である。視覚的な色の変化により水素ガスの漏えいを検知することから、水素ガス検知用部材に求められる光吸収特性としては、水素吸着により透過率が５０％以上変化する特性を有していることが好ましい。該光吸収特性を達成するためには、例えば、投入スパッタリング電力が５０Ｗ、基板とターゲットとの間の距離が１０ｃｍで、アルゴンと酸素の混合雰囲気でスパッタリングを行う場合、酸素ガス圧は１４～８０ｍＰａ、アルゴンガス圧は１３０～１７０ｍＰａとすることが好ましい。更に好ましくは、酸素ガス圧は１５～４０ｍＰａ、アルゴンガス圧は１４０～１６０ｍＰａである。スパッタリングをアルゴンと酸素の混合雰囲気で行う場合、水素吸着による透過率の変化が５０％以上を達成するためには、厳密には他のスパッタリング条件にも依存するが、酸素ガスの比率は、全ガス圧（酸素ガス圧とアルゴンガス圧の和）の１０～３０％の範囲内に制御すればよい。 Sputtering is preferably a mixed atmosphere of argon and oxygen. The substrate temperature at the time of sputtering is preferably room temperature (20 ° C.). Since the leakage of hydrogen gas is detected by a visual color change, the light absorption characteristic required for the hydrogen gas detection member is that the transmittance changes by 50% or more due to hydrogen adsorption. preferable. In order to achieve the light absorption characteristics, for example, when the sputtering power is 50 W, the distance between the substrate and the target is 10 cm, and sputtering is performed in a mixed atmosphere of argon and oxygen, the oxygen gas pressure is 14 to 80 mPa. The argon gas pressure is preferably 130 to 170 mPa. More preferably, the oxygen gas pressure is 15 to 40 mPa and the argon gas pressure is 140 to 160 mPa. When sputtering is performed in a mixed atmosphere of argon and oxygen, in order to achieve a transmittance change of 50% or more due to hydrogen adsorption, strictly depending on other sputtering conditions, the ratio of oxygen gas is The gas pressure (the sum of oxygen gas pressure and argon gas pressure) may be controlled within a range of 10 to 30%.
　触媒金属の堆積は、パルスレーザーデポジション法、高周波スパッタリング法、直流スパッタリング法、分子線エピタキシー法、又は真空蒸着法により行うことができ、基板の耐熱温度以下にて堆積できるものであればいずれの方法でもよい。例えば、高周波スパッタリング法により触媒金属を堆積する場合は、堆積条件として、スパッタリング電力は２５Ｗ～５０Ｗ、基板は室温で、アルゴンガス圧が１３０～１７０ｍＰａである雰囲気中で行うことが好ましい。 The catalyst metal can be deposited by a pulse laser deposition method, a high frequency sputtering method, a direct current sputtering method, a molecular beam epitaxy method, or a vacuum evaporation method, and any metal can be deposited at a temperature lower than the heat resistant temperature of the substrate. The method may be used. For example, when the catalytic metal is deposited by a high-frequency sputtering method, the deposition conditions are preferably an atmosphere in which the sputtering power is 25 W to 50 W, the substrate is at room temperature, and the argon gas pressure is 130 to 170 mPa.
　触媒金属を形成する金属元素としては、貴金属元素（具体的には、白金、パラジウム、ロジウム、イリジウム、ルテニウム、及びオスミウム）、コバルト、ニッケル及び銅から選ばれる金属元素であることが好ましく、更には、白金、パラジウム、コバルト、ニッケル、又は銅を用いることが、より効果的に水素ガス検知を行うことができる観点から好ましい。更には、これらのうち、複数種類の金属元素を用いてもよい。 The metal element forming the catalyst metal is preferably a metal element selected from noble metal elements (specifically, platinum, palladium, rhodium, iridium, ruthenium, and osmium), cobalt, nickel, and copper, It is preferable to use platinum, palladium, cobalt, nickel, or copper from the viewpoint that hydrogen gas can be detected more effectively. Further, among these, a plurality of types of metal elements may be used.
　なお、薄膜シート状の水素ガス検知用部材の形成方法の詳細については、例えば、特開２００５－３４５３３８号公報、特開２００７－７１８６６号公報、特開２００７－１５５４３６号公報、特開２００７－２７８７４４号公報等に記載されている方法を参考にすることができる。 The details of the method for forming the thin-film sheet-shaped hydrogen gas detection member are disclosed in, for example, JP-A-2005-345338, JP-A-2007-71866, JP-A-2007-155436, and JP-A-2007-278744. Reference can be made to the methods described in the Gazettes.
　［コア・シェル構造粒子状の水素ガス検知用部材］
　コア・シェル構造を有する粒子状の水素ガス検知用部材（１Ｐ）の調製方法としては、水溶液環境下で、順次粒子成長を行い、コア・シェル構造を有する粒子を形成する方法が好ましい。 [Particulate hydrogen gas detection member with core / shell structure]
As a method for preparing the particulate hydrogen gas detecting member (1P) having a core / shell structure, a method of sequentially forming particles in an aqueous solution environment to form particles having a core / shell structure is preferable.
　具体的には、図３及び図４に記載の製造工程フローに従って、調製することができる。 Specifically, it can be prepared according to the manufacturing process flow described in FIGS.
　主要な製造工程としては、図３に示すように、酸化セリウムを含有するコア粒子を形成し、コア粒子上に酸化タングステンを含有する第１のシェル部を形成し、第１のシェル部上に触媒金属元素を含む第２のシェル部を形成する工程等を備えている。詳しくは、
　（工程ａ）
　硝酸セリウム、硝酸、アンモニア等を用いて、水溶液中で酸化セリウムの微結晶の晶出及び成長を行い、酸化セリウムから構成されるコア粒子（コア部）を形成する工程。 As shown in FIG. 3, the main manufacturing process is to form core particles containing cerium oxide, to form a first shell portion containing tungsten oxide on the core particles, and on the first shell portion. A step of forming a second shell portion containing a catalytic metal element. For more information,
(Process a)
A step of crystallizing and growing cerium oxide microcrystals in an aqueous solution using cerium nitrate, nitric acid, ammonia or the like to form core particles (core portion) composed of cerium oxide.
　（工程ｂ）
　上記調製した酸化セリウムのコア粒子を含有する懸濁液を用いて、タングステン酸ナトリウム及び硝酸等を用いて、コア粒子表面にタングステン酸（Ｈ２ＷＯ４）から構成される第１のシェル部を形成する工程。 (Process b)
Using the suspension containing the cerium oxide core particles prepared above, a first shell portion composed of tungstic acid (H 2 WO 4 ) is formed on the core particle surface using sodium tungstate, nitric acid, or the like. Forming step.
　（工程ｃ）
　上記調製したコア粒子／第１のシェル部（酸化セリウム／タングステン酸（Ｈ２ＷＯ４））から構成されるコア・シェル粒子を含む懸濁液に、触媒金属塩を含む水溶液を添加して、コア・シェル粒子の第１のシェル部表面に、金属触媒を堆積、担持させて、第２のシェル部として、触媒金属元素含有層を形成する工程。 (Process c)
An aqueous solution containing a catalyst metal salt is added to a suspension containing core / shell particles composed of the core particles / first shell part (cerium oxide / tungstic acid (H 2 WO 4 )) prepared above, A step of depositing and supporting a metal catalyst on the surface of the first shell portion of the core-shell particles to form a catalytic metal element-containing layer as the second shell portion.
　（工程ｄ）
　以上により調製したコア・シェル粒子を含む懸濁液（粒子分散液）を、濃縮、固液分離、及び洗浄を行い、不要の塩類等を除去した後、乾燥する工程。 (Process d)
A step of concentrating, solid-liquid separating, and washing the suspension (core dispersion) containing core / shell particles prepared as described above to remove unnecessary salts and the like and then drying.
　（工程ｅ）
　最後に、焼成処理を行って、タングステン酸（Ｈ２ＷＯ４）を酸化タングステン（ＨｘＷＯ３）に酸化して、薄黄緑色のコア・シェル粒子状の水素ガス検知用部材を調製する工程。 (Process e)
Finally, a baking process is performed to oxidize tungstic acid (H 2 WO 4 ) to tungsten oxide (H x WO 3 ) to prepare a light yellow-green core / shell particle hydrogen gas detection member. .
　次いで、コア・シェル粒子状の水素ガス検知用部材の調製方法について説明する。 Next, a method for preparing a core / shell particle-shaped hydrogen gas detection member will be described.
　（コア粒子の調製：工程ａ）
　第１段階は、セリウム（III）塩の溶液である開始溶液を調製する。セリウム（III）塩として、例えば、硝酸セリウム（III）、塩化セリウム（III）、硫酸セリウム（III）、炭酸セリウム（III）及びこれらの塩の混合物（硝酸塩／塩化物の混合物等）を使用することができるが、硝酸セリウム（III）を用いることが好ましい。 (Preparation of core particles: Step a)
The first stage prepares an initial solution that is a solution of a cerium (III) salt. As the cerium (III) salt, for example, cerium (III) nitrate, cerium (III) chloride, cerium (III) sulfate, cerium carbonate (III) and a mixture of these salts (such as a nitrate / chloride mixture) are used. Although it is possible to use cerium (III) nitrate.
　以下、セリウム（III）塩の代表例として、硝酸セリウム（III）を用いる方法について説明する。 Hereinafter, a method using cerium (III) nitrate as a representative example of the cerium (III) salt will be described.
　硝酸セリウムを含む開始溶液は、セリウムが溶液中において安定した状態で存在させるため酸性度を調整することが好ましく、例えば、硝酸を用いて、開始溶液である混合液のｐＨを制御する。 It is preferable to adjust the acidity of the starting solution containing cerium nitrate because cerium is present in a stable state in the solution. For example, nitric acid is used to control the pH of the mixed solution that is the starting solution.
　この第１段階で調製した混合液は、不活性ガスを通気することにより、事前に脱ガス処理を施すことができる。不活性ガスとしては、例えば、窒素ガスやアルゴンガスを適用することができる。 The mixed liquid prepared in the first stage can be degassed in advance by passing an inert gas. As the inert gas, for example, nitrogen gas or argon gas can be applied.
　次いで、第２段階では、混合溶液と塩基水溶液とを反応させる。塩基水溶液としては、アルカリ金属又はアルカリ土類金属水酸化物、及びアンモニア水を挙げることができる。また、第２級アミン、第３級アミン又は第４級アミンも使用することができる。上記の中でも、アミン類又はアンモニア水が好ましい。これは、アミン類及びアンモニア水を用いることにより、アルカリ金属カチオン又はアルカリ土類金属カチオンによる汚染のリスクが軽減される。この塩基溶液（例えば、アンモニア水）に、上記調製した混合溶液を撹拌しながら添加する。この時も、不活性ガスを用いて通気することにより、脱ガス処理することができる。 Next, in the second stage, the mixed solution and the base aqueous solution are reacted. Examples of the aqueous base solution include alkali metal or alkaline earth metal hydroxide, and aqueous ammonia. Secondary amines, tertiary amines or quaternary amines can also be used. Among the above, amines or aqueous ammonia is preferable. This reduces the risk of contamination by alkali metal cations or alkaline earth metal cations by using amines and aqueous ammonia. The mixed solution prepared above is added to this base solution (for example, aqueous ammonia) with stirring. Also at this time, degassing can be performed by aeration using an inert gas.
　上記の第２段階は、閉鎖反応装置又は半閉鎖反応装置のいずれかにおいて、不活性ガスによるスイープを行いながら、不活性雰囲気下で行うことが好ましい。接触は、一般に、攪拌反応装置内で行われる。 The second stage is preferably performed in an inert atmosphere while sweeping with an inert gas in either a closed reactor or a semi-closed reactor. Contact is generally carried out in a stirred reactor.
　この第２段階は、一般に、周囲温度（２０～２５℃）又は最高５０℃の温度にて行われる。 This second stage is generally performed at ambient temperature (20-25 ° C.) or at a maximum temperature of 50 ° C.
　第３段階は、上記調製した酸化セリウム懸濁液に対し熱処理を行う。この熱処理は、おおむね６０～９５℃の範囲で温度を維持しながら、１～５時間程度の熱処理を行う。この処理の継続時間は、数分から数時間になり得る。また、この熱処理も、不活性雰囲気下で行われる。 In the third stage, the prepared cerium oxide suspension is heat-treated. This heat treatment is performed for about 1 to 5 hours while maintaining the temperature in the range of about 60 to 95 ° C. The duration of this process can be from a few minutes to a few hours. This heat treatment is also performed in an inert atmosphere.
　最後の段階で、酸性化処理及び洗浄処理を行う。 At the final stage, acidification and cleaning are performed.
　酸性化は、一般に、第３段階の最後で得られた懸濁液を冷却した後に、酸の添加によって行われる。酸としては無機酸又は有機酸のいずれも使用することができるが、硝酸を用いることが好ましい。添加される酸の量は、酸性化後の懸濁液のｐＨが２～４の範囲内となる条件で添加する。この作業は、通常の大気環境下で行うことができる。 Acidification is generally performed by adding an acid after cooling the suspension obtained at the end of the third stage. As the acid, either an inorganic acid or an organic acid can be used, but nitric acid is preferably used. The amount of acid added is such that the pH of the suspension after acidification is in the range of 2-4. This operation can be performed in a normal atmospheric environment.
　酸性化に続いて、洗浄が行われる。その目的は、懸濁液から可溶性種、原則的に塩を除去することにあり、固体／液体を分離して又は分離することなく、様々なやり方で行うことができる。 Washing is performed following acidification. Its purpose is to remove soluble species, in principle salts, from the suspension, which can be carried out in various ways, with or without separating the solid / liquid.
　（タングステン酸シェルの形成：工程ｂ）
　第１段階としては、上記調製した酸化セリウムにより構成されるコア粒子を含む懸濁液に対し、タングステン酸塩を含む水溶液を添加して、懸濁液を調製する。 (Tungstic acid shell formation: Step b)
As a first step, an aqueous solution containing tungstate is added to a suspension containing core particles composed of the prepared cerium oxide to prepare a suspension.
　次いで、酸化セリウムコア粒子とタングステン酸塩を含む懸濁液に、酸を添加する。この時、使用する酸としては、無機酸又は有機酸のいずれも使用することができるが、硝酸を用いることが好ましい。添加される酸の量は、酸性化後の懸濁液のｐＨが１以下となる条件で添加する。酸の添加は、室温下で撹拌しながら２０～６０分かけてゆっくり添加し、酸化セリウムコア粒子の表面に、タングステン酸（Ｈ２ＷＯ４）の第１のシェル層を形成する。 Next, an acid is added to the suspension containing the cerium oxide core particles and the tungstate. At this time, as the acid to be used, either an inorganic acid or an organic acid can be used, but nitric acid is preferably used. The amount of acid added is such that the pH of the suspension after acidification is 1 or less. The acid is slowly added over 20 to 60 minutes with stirring at room temperature to form a first shell layer of tungstic acid (H 2 WO 4 ) on the surface of the cerium oxide core particles.
　次いで、遠心分離による粒子の沈降、デカンテーションによる上澄み液の排液、洗浄用の純水の添加の工程を４～１０回程度繰り返して行い、不要な塩類の除去を行い、コア層が酸化セリウムで、第１のシェル層がタングステン酸（Ｈ２ＷＯ４）より構成されるコア・シェル粒子Ａを含む懸濁液を調製する。 Next, the steps of sedimentation of particles by centrifugation, draining of the supernatant by decantation, and addition of pure water for washing are repeated about 4 to 10 times to remove unnecessary salts, and the core layer is made of cerium oxide. Then, a suspension containing the core-shell particles A in which the first shell layer is composed of tungstic acid (H 2 WO 4 ) is prepared.
　（触媒金属元素層の形成：工程ｃ）
　次いで、上記酸化セリウム／タングステン酸（Ｈ２ＷＯ４）より構成されるコア・シェル粒子Ａを含む懸濁液に対し、触媒金属元素を含む化合物、例えば、Ｈ２ＰｔＣｌ６／６Ｈ２Ｏ、ＰｄＣｌ２、Ｃｏ（ＮＯ３）２、Ｎｉ（ＮＯ３）２、Ｃｕ（ＮＯ３）２等を含む水溶液を、ゆっくりと添加し、この状態を３～１０時間維持させて、タングステン酸（Ｈ２ＷＯ３）層表面に、触媒金属元素を担持させた第２のシェル層を形成して、コア粒子が酸化セリウムで、第１のシェル層がタングステン酸（Ｈ２ＷＯ４）、第２のシェル層が触媒金属元素により構成されるコア・シェル粒子Ｂを含む懸濁液を調製する。 (Formation of catalytic metal element layer: step c)
Next, a compound containing a catalytic metal element, such as H 2 PtCl 6 / 6H 2 O, PdCl, is added to the suspension containing the core-shell particles A composed of the cerium oxide / tungstic acid (H 2 WO 4 ). 2 , an aqueous solution containing Co (NO 3 ) 2 , Ni (NO 3 ) 2 , Cu (NO 3 ) 2, etc. is slowly added, and this state is maintained for 3 to 10 hours to obtain tungstic acid (H 2 WO 3 ) A second shell layer supporting a catalytic metal element is formed on the surface of the layer, the core particles are cerium oxide, the first shell layer is tungstic acid (H 2 WO 4 ), and the second shell layer A suspension containing the core-shell particles B composed of a catalytic metal element is prepared.
　（焼成処理によるタングステン酸（Ｈ２ＷＯ４）の酸化タングステン（ＨｘＷＯ３）への変換：工程ｅ）
　上記調製したコア・シェル粒子Ｂを含む懸濁液を、エバポレーター等を用いて水分を除いた後、得られたコア・シェル粒子Ｂを８０～１５０℃で、１～５時間乾燥させた後、１５０～４００℃の温度範囲で、３０分～３時間の焼成処理を施すことにより、タングステン酸（Ｈ２ＷＯ４）層を、酸化タングステン（ＨｘＷＯ３）層に変化させることにより、コア・シェル構造の水素ガス検知用部材（１Ｐ）を得ることができる。 (Conversion of tungstic acid (H 2 WO 4 ) to tungsten oxide (H x WO 3 ) by baking treatment: Step e)
The suspension containing the core / shell particles B prepared above was removed of moisture using an evaporator or the like, and the obtained core / shell particles B were dried at 80 to 150 ° C. for 1 to 5 hours. By subjecting the tungstic acid (H 2 WO 4 ) layer to a tungsten oxide (H x WO 3 ) layer by performing a baking treatment for 30 minutes to 3 hours in a temperature range of 150 to 400 ° C. The shell structure hydrogen gas detection member (1P) can be obtained.
　このコア・シェル構造の水素ガス検知用部材（１Ｐ）では、前述のように、無色の酸化タングステン（ＨｘＷＯ３）が水素ガスと反応し、酸化タングステン（ＨｙＷＯ３）に変化することにより、青色への色相変化や透過率の変化を検知することにより、水素ガスを検知する。 In the core-shell structure hydrogen gas detection member (1P), as described above, colorless tungsten oxide (H x WO 3 ) reacts with hydrogen gas and changes to tungsten oxide (H y WO 3 ). Thus, hydrogen gas is detected by detecting a change in hue to blue or a change in transmittance.
　コアを構成する酸化セリウム粒子の直径としては、５０～２００ｎｍの範囲内であり、酸化タングステン層の厚さは、２５～１００ｎｍの範囲内であり、触媒金属元素層の厚さは、１～２０ｎｍの範囲内とすることが好ましい。 The diameter of the cerium oxide particles constituting the core is in the range of 50 to 200 nm, the thickness of the tungsten oxide layer is in the range of 25 to 100 nm, and the thickness of the catalytic metal element layer is 1 to 20 nm. It is preferable to be within the range.
　次いで、図４を用いて、コア・シェル粒子状の水素ガス検知用粒子の具体的な製造例について説明する。 Next, a specific production example of the core / shell particles for detecting hydrogen gas will be described with reference to FIG.
　図４は、コア・シェル粒子状の水素ガス検知用粒子の製造工程の具体的なフローを示す図である。 FIG. 4 is a diagram showing a specific flow of the manufacturing process of core / shell particles of hydrogen gas detection particles.
　（酸化セリウム含有層より構成するコア粒子の形成：工程ａ及び工程ａ１）
　はじめに、図４に記載の反応釜（１０１）を有する工程ａ及び添加剤の調製釜（１０５）を有する工程ａ１を用いて、酸化セリウムより構成されるコア粒子を調製する。 (Formation of core particles composed of a cerium oxide-containing layer: step a and step a1)
First, core particles composed of cerium oxide are prepared using step a having the reaction vessel (101) shown in FIG. 4 and step a1 having an additive preparation vessel (105).
　例えば、工程ａ１の調製釜（１０５）に、硝酸セリウム水溶液と硝酸水溶液を添加し、Ｎ２ガスで通気しながら、撹拌機（１０７）で撹拌して混合液（１０６）を調製する。 For example, a cerium nitrate aqueous solution and a nitric acid aqueous solution are added to the preparation kettle (105) of step a1, and the mixture (106) is prepared by stirring with a stirrer (107) while venting with N 2 gas.
　一方、反応釜（１０１）に、母液（１０２）としてアンモニア水溶液を添加し、Ｎ２ガスで通気しながら、撹拌機（１０３）で撹拌する。 On the other hand, an aqueous ammonia solution is added as a mother liquor (102) to the reaction kettle (101), and stirred with a stirrer (103) while venting with N 2 gas.
　次いで、反応釜（１０１）のアンモニア水溶液中に、送液ポンプ（１０８）を用いて、工程ａ１の調製釜（１０５）より硝酸セリウム水溶液と硝酸水溶液の混合液（１０６）を、Ｎ２ガス雰囲気下で撹拌しながら添加して、懸濁液を調製する。 Next, the mixed solution (106) of the cerium nitrate aqueous solution and the nitric acid aqueous solution is transferred from the preparation kettle (105) of step a1 into the aqueous ammonia solution in the reaction kettle (101) using an N 2 gas atmosphere. Add with stirring under to prepare a suspension.
　次いで、Ｎ２ガスを通気撹拌しながら、懸濁液を６０～９０℃の温度範囲内まで昇温し、その状態を一定時間維持する。 Next, while the N 2 gas is aerated and stirred, the suspension is heated to a temperature range of 60 to 90 ° C., and this state is maintained for a certain time.
　次いで、懸濁液を室温程度まで降温した後、硝酸を添加してｐＨを２．０まで下げたのち、Ｎ２ガスの通気を停止して、酸化セリウム粒子（コア粒子）を含む懸濁液（１０４）を調製する。 Next, after the temperature of the suspension is lowered to about room temperature, nitric acid is added to lower the pH to 2.0, and then the aeration of N 2 gas is stopped, and the suspension contains cerium oxide particles (core particles). (104) is prepared.
　（タングステン酸による第１のシェル部の形成：工程ｂ及び工程ｂ１）
　次いで、図４に記載の反応釜（１１１）を有する工程ｂ及び２系統の添加剤調製釜（１１５）を有する工程ｂ１（図４では代表して１系統のみを示す。）を用いて、工程ａで調製した酸化セリウムより構成されるコア粒子表面に、第１のシェル層としてタングステン酸を被覆して、コア・シェル型粒子を調製する。 (Formation of the first shell portion with tungstic acid: step b and step b1)
Next, using the step b having the reaction kettle (111) shown in FIG. 4 and the step b1 having only two systems of additive preparation kettle (115) (FIG. 4 representatively shows only one system). A core-shell type particle is prepared by coating tungstic acid as the first shell layer on the surface of the core particle composed of cerium oxide prepared in a.
　はじめに、調製釜（１１５）に、タングステン酸ナトリウム水溶液（１１６）を準備する。また、図には示していないが、他系統の調製釜（１１５ｂ）には、硝酸水溶液（１１６ｂ）を準備する。 First, a sodium tungstate aqueous solution (116) is prepared in a preparation kettle (115). Further, although not shown in the figure, a nitric acid aqueous solution (116b) is prepared in the preparation kettle (115b) of another system.
　反応釜（１１１）に上記調製した酸化セリウム粒子（コア粒子）を含む懸濁液（１０４）を貯留し、当該懸濁液（１０４）を撹拌しながら、送液ポンプ（１１８）を用いて、調製釜（１１５）よりタングステン酸ナトリウム水溶液（１１６）を添加する。 In the reaction kettle (111), the suspension (104) containing the cerium oxide particles (core particles) prepared above is stored, and while the suspension (104) is stirred, using the liquid feed pump (118), A sodium tungstate aqueous solution (116) is added from the preparation kettle (115).
　次いで、同懸濁液（１０４）に、送液ポンプ（１１８ｂ）を用いて、他系統（不図示）の調製釜（１１５ｂ）より硝酸水溶液（１１６ｂ）を添加して、ｐＨを１．０程度まで低下させ、この状態を一定時間維持して、酸化セリウム（ＣｅＯ２）がコア粒子で、その表面にタングステン酸（Ｈ２ＷＯ４）の第１のシェル部を形成したコア・シェル粒子を含む懸濁液（１１２、ＣｅＯ２／Ｈ２ＷＯ４懸濁液）を調製する。 Next, a nitric acid aqueous solution (116b) is added to the suspension (104) from a preparation kettle (115b) of another system (not shown) using a liquid feed pump (118b), so that the pH is about 1.0. In this state, cerium oxide (CeO 2 ) is a core particle, and includes a core-shell particle in which a first shell portion of tungstic acid (H 2 WO 4 ) is formed on the surface. A suspension (112, CeO 2 / H 2 WO 4 suspension) is prepared.
　（最表面に触媒金属元素含有層（第２のシェル部）の形成：工程ｃ及び工程ｃ１）
　次いで、図４に記載の反応釜（１２１）を有する工程ｃ及び調製釜（１２５）を有する工程ｃ１を用いて、上記調製したコア・シェル型粒子の表面に触媒金属元素含有層を第２のシェル部として担持させて、最終的なコア・シェル型粒子を調製する。 (Formation of catalytic metal element-containing layer (second shell part) on outermost surface: step c and step c1)
Next, using the step c having the reaction kettle (121) shown in FIG. 4 and the step c1 having the preparation kettle (125), a catalyst metal element-containing layer is formed on the surface of the prepared core-shell type particles. The final core-shell type particles are prepared by being supported as a shell part.
　調製釜（１２５）に、例えば、触媒金属元素含有化合物としてＨ２ＰｔＣｌ６・６Ｈ２Ｏ水溶液（１２６）を準備する。 Preparation kettle (125), for example, to prepare a H 2 PtCl 6 · 6H 2 O aqueous solution as a catalyst metal element-containing compound (126).
　一方、反応釜（１２１）に、上記調製したＣｅＯ２／Ｈ２ＷＯ４懸濁液（１１２）を準備する。 On the other hand, the prepared CeO 2 / H 2 WO 4 suspension (112) is prepared in the reaction kettle (121).
　次いで、反応釜（１２１）のＣｅＯ２／Ｈ２ＷＯ４懸濁液（１１２）に、送液ポンプ（１２８）を用いて、調製釜（１２５）よりＨ２ＰｔＣｌ６・６Ｈ２Ｏ水溶液（１２６）を、撹拌しながら、所定時間を要して添加し、タングステン酸（Ｈ２ＷＯ４）層（第１のシェル部）上に触媒として白金を含む触媒金属元素含有層（第２のシェル部）を担持したＣｅＯ２／Ｈ２ＷＯ４／Ｐｔ懸濁液（１２７）を調製する。 Then, the CeO 2 / H 2 WO 4 suspension reactor (121) (112), using a feeding pump (128), prepared kettle (125) from H 2 PtCl 6 · 6H 2 O solution (126 ) Is added over a predetermined time with stirring, and a catalytic metal element-containing layer (second shell part) containing platinum as a catalyst on the tungstic acid (H 2 WO 4 ) layer (first shell part) ) Supported CeO 2 / H 2 WO 4 / Pt suspension (127).
　コア・シェル型粒子において、触媒金属を形成する金属元素としては、白金、パラジウム、ロジウム、イリジウム、ルテニウム、オスミウム、コバルト、ニッケル及び銅から選ばれる金属元素であることが好ましく、更には、白金、パラジウム、コバルト、ニッケル、又は銅を用いることが、より効果的に水素ガス検知を行うことができる観点から好ましい。これらのうち、複数種類の金属元素を用いてもよい。 In the core-shell type particles, the metal element that forms the catalyst metal is preferably a metal element selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, cobalt, nickel, and copper. It is preferable to use palladium, cobalt, nickel, or copper from the viewpoint that hydrogen gas can be detected more effectively. Of these, a plurality of types of metal elements may be used.
　（乾燥及び焼成処理：工程ｄ及び工程ｅ）
　上記調製したＣｅＯ２／Ｈ２ＷＯ４／Ｐｔ懸濁液（１２７）を、濾過・固液分離・洗浄工程（工程ｄ）で、濾過・固液分離・洗浄装置（１３１）を用いて、遠心分離、デカンデーション法による上澄み液の排液、純水の添加の操作を繰り返して、洗浄処理を行う。 (Drying and firing treatment: Step d and Step e)
The above-prepared CeO 2 / H 2 WO 4 / Pt suspension (127) is centrifuged in a filtration / solid-liquid separation / washing step (step d) using a filtration / solid-liquid separation / washing device (131). The washing process is performed by repeating the steps of separation, draining the supernatant liquid by decantation method, and adding pure water.
　次いで、焼成工程（工程ｅ）で水分を除いた紛体を、焼成装置（１４１）を用いて加熱乾燥した後、１５０～４００℃の温度範囲で焼成処理を施して、Ｈ２ＷＯ４をＨｘＷＯ３に変換して、ＣｅＯ２／ＨｘＷＯ３／Ｐｔから構成されるコア・シェル型粒子である水素ガス検知用部材（１Ｐ）を調製する。ここで、ｘは０．５以上、０．８未満の数値を取る。 Next, the powder from which moisture has been removed in the firing step (step e) is heat-dried using a firing device (141), and then subjected to a firing treatment in a temperature range of 150 to 400 ° C., thereby converting H 2 WO 4 into H x converted to WO 3, to prepare a CeO 2 / H x WO 3 / Pt hydrogen gas detecting member is a core-shell particles composed of (1P). Here, x takes a numerical value of 0.5 or more and less than 0.8.
　《水素ガス検知システムの基本構成》
　図５Ａ及び図５Ｂに、水素ガス検知用部材を用いた水素ガス検知システムの基本構成の一例を示す。 <Basic configuration of hydrogen gas detection system>
5A and 5B show an example of a basic configuration of a hydrogen gas detection system using a hydrogen gas detection member.
　図５Ａに示した水素ガス検知測定装置（５０）は、光透過型の水素ガス検知用部材（１）を用いた水素ガス検知システムの一例を示すものであり、中央に、光透過性の基板（２）、酸化セリウム含有層（３）、酸化タングステン含有層（４）及び触媒金属元素含有層（５）から構成される水素ガス検知用部材（１）を配置し、左側に光源部（５１）を配置し、右側には、水素ガス検知用部材（１）を通過してきた光量（透過光）を測定する分光光度計（５２）を配置する。この時、分光光度計（５２）による測定波長としては、酸化タングステン含有層（４）の透過率変化の検出に感度の高い６００ｎｍの波長の光を用いることが好ましい。 The hydrogen gas detection and measurement apparatus (50) shown in FIG. 5A shows an example of a hydrogen gas detection system using a light transmission type hydrogen gas detection member (1), and a light transmissive substrate is provided at the center. (2) A hydrogen gas detection member (1) composed of a cerium oxide-containing layer (3), a tungsten oxide-containing layer (4), and a catalytic metal element-containing layer (5) is disposed, and a light source section (51 ) And a spectrophotometer (52) for measuring the amount of light (transmitted light) that has passed through the hydrogen gas detection member (1) is arranged on the right side. At this time, as a wavelength measured by the spectrophotometer (52), it is preferable to use light having a wavelength of 600 nm which is highly sensitive for detecting a change in transmittance of the tungsten oxide-containing layer (4).
　はじめに、基準として、水素ガスを除去した空気をガス流入口（５４）より水素ガス検知測定装置（５０）内に流入させ、ガス流出口（５５）より流出させながら、光源部（５１）より、可視光線（Ｌ）を照射し、波長６００ｎｍの光における空気雰囲気下での光透過率ＴＰ１（全照射光に対する光透過光の比率（％））を測定する。 First, as a reference, air from which hydrogen gas has been removed flows from the gas inlet (54) into the hydrogen gas detection and measurement device (50), and flows out from the gas outlet (55). Visible light (L) is irradiated, and light transmittance TP1 (ratio of light transmitted light to total irradiated light (%)) in an air atmosphere with light having a wavelength of 600 nm is measured.
　次いで、水素ガス検知測定装置（５０）内に流入するガスを、１体積％の水素ガスを含む空気に変更して、同様に１体積％水素ガスに暴露した時の波長６００ｎｍの光における光透過率ＴＰ２を測定し、下式（１）に従い、水素ガス濃度に対する各水素ガス検知用部材の光透過率変化（％）を測定し、これを水素ガス検知用部材の水素ガス検知能の尺度（検量線）として求める。 Next, the gas flowing into the hydrogen gas detection / measurement device (50) is changed to air containing 1% by volume hydrogen gas, and similarly, light is transmitted through light having a wavelength of 600 nm when exposed to 1% by volume hydrogen gas. The rate TP2 is measured, and the change in light transmittance (%) of each hydrogen gas detection member with respect to the hydrogen gas concentration is measured according to the following formula (1). This is a measure of the hydrogen gas detection capability of the hydrogen gas detection member ( Calculated as a calibration curve).
　式（１）
　　　光透過率変化（％）＝ＴＰ２／ＴＰ１×１００
　図５Ｂで示した水素ガス検知測定装置（５０）は、上記図５Ａで示した構成とは異なり、反射型の水素ガス検知用部材（１）を用いた際の水素ガス検知システムの一例を示すものであり、基板（２ａ）が光不透過性の材料で構成され、反射光を分光光度計（５２）で測定して求める方法である。 Formula (1)
Light transmittance change (%) = TP2 / TP1 × 100
The hydrogen gas detection and measurement apparatus (50) shown in FIG. 5B shows an example of a hydrogen gas detection system when the reflective hydrogen gas detection member (1) is used, unlike the configuration shown in FIG. 5A. In this method, the substrate (2a) is made of a light-impermeable material and the reflected light is measured by a spectrophotometer (52).
　《水素ガス検知システム》
　図６に、水素ガス検知用部材を用いた水素ガス検知システムの一例を示す。 《Hydrogen gas detection system》
FIG. 6 shows an example of a hydrogen gas detection system using a hydrogen gas detection member.
　図６に示すように、水素ガスを使用している機器、例えば、水素ガスボンベ（Ｃ）や水素ガスタンク（Ｄ）が配置されている環境下で、水素ガス検知用部材は有効に使用することができる。 As shown in FIG. 6, the hydrogen gas detection member can be used effectively in an environment where hydrogen gas is used, for example, in an environment where a hydrogen gas cylinder (C) and a hydrogen gas tank (D) are arranged. it can.
　水素ガス検知用部材が薄膜シート状の形態であれば、室内の壁面（Ｂ）や、水素ガスボンベ（Ｃ）表面、水素ガスタンク（Ｄ）表面の一部又は全面に貼り付けて配置することができる。 If the member for detecting hydrogen gas is in the form of a thin film sheet, it can be disposed on the wall surface (B) of the room, the surface of the hydrogen gas cylinder (C), the surface of the hydrogen gas tank (D) or the entire surface. .
　また、本発明の水素ガス検知用部材がコア・シェル型粒子の形態であれば、バインダーに分散させて塗料として調製した後、室内の天井（Ａ）や壁面（Ｂ）、水素ガスボンベ（Ｃ）や水素ガスタンク（Ｄ）の外壁、水素ガスタンク（Ｄ）の配管（Ｅ）、バルブ（Ｆ）、ポンプ（Ｇ）等に塗装して設けることができる。 Further, if the hydrogen gas detection member of the present invention is in the form of core / shell type particles, it is dispersed in a binder and prepared as a paint, and then the indoor ceiling (A), wall surface (B), hydrogen gas cylinder (C). Or the outer wall of the hydrogen gas tank (D), the pipe (E), the valve (F), the pump (G), etc. of the hydrogen gas tank (D).
　本実施形態の水素ガス検知システムは、水素ガス容器設置室（６１）に設置された水素ガス検知用部材の光透過率や色相の変化を検知するための光学測定装置（６２）と、光学測定装置（６２）で入手した色相変化を監視する検知装置（６３）と、警報装置（６４）と、バルブ（Ｆ）やポンプ（Ｇ）を制御するためのガス供給制御部（６５）と、を備えている。本システムは、各所に設置した水素ガス検知用部材が検知した水素ガスの漏えいを、光学測定装置（６２）及び検知装置（６３）によって検知する。具体的には、光学測定装置（６２）を用いて反射光を受光することにより、水素ガス検知用部材の色相の変化を測定し、検知装置（６３）によって、反射光の色調や反射光量が事前に規定している閾値（規定値）を外れた場合に、水素ガスの漏えいが発生したと判定する。検知装置（６３）が漏えいありと判定した場合、検知装置（６３）から送信される情報に基づいて、警報装置（６４）が警報を発するとともに、水素ガス漏れの発生源であるバルブ（Ｆ）の遮断やポンプ（Ｇ）の駆動を停止させる制御信号（６６）を、ガス供給制御部（６５）より送信する。 The hydrogen gas detection system of the present embodiment includes an optical measurement device (62) for detecting a change in light transmittance and hue of a hydrogen gas detection member installed in the hydrogen gas container installation chamber (61), and an optical measurement. A detection device (63) for monitoring the hue change obtained by the device (62), an alarm device (64), and a gas supply control unit (65) for controlling the valve (F) and the pump (G). I have. In this system, leakage of hydrogen gas detected by hydrogen gas detection members installed in various places is detected by the optical measurement device (62) and the detection device (63). Specifically, the change in the hue of the hydrogen gas detection member is measured by receiving the reflected light using the optical measurement device (62), and the color tone and the amount of reflected light of the reflected light are measured by the detection device (63). When the threshold value (specified value) specified in advance is deviated, it is determined that the leakage of hydrogen gas has occurred. When the detection device (63) determines that there is a leak, the alarm device (64) issues an alarm based on the information transmitted from the detection device (63), and the valve (F) that is the source of hydrogen gas leakage The gas supply control unit (65) transmits a control signal (66) for shutting off the power supply and stopping the pump (G).
　以下、本発明の具体的な実施例について説明するが、本発明はこれらに限定されるものではない。なお、実施例において「部」又は「％」の表示が用いられるが、特に断りが無い限り「質量部」又は「質量％」を表す。なお、以下の説明で、各構成要素の後に括弧で表示している数字は、関連する図に表示している各構成部材の番号を示してある。 Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless there is particular notice, it represents "mass part" or "mass%". In the following description, the number displayed in parentheses after each component indicates the number of each component displayed in the related figure.
　実施例１
　《薄膜シート状の水素ガス検知用部材の作製》
　以下の方法に従って、薄膜シート状の水素ガス検知用部材１～６を作製した。 Example 1
<< Production of thin-film sheet-like hydrogen gas detection member >>
In accordance with the following method, thin film sheet-like hydrogen gas detection members 1 to 6 were produced.
　〔水素ガス検知用部材１の作製〕
　下記の方法に従って、図１Ｂに相当する構成を有する薄膜シート状の水素ガス検知用部材１（１Ｓ）を作製した。 [Production of hydrogen gas detection member 1]
In accordance with the following method, a thin-film sheet-shaped hydrogen gas detection member 1 (1S) having a configuration corresponding to FIG. 1B was produced.
　（基板の準備）
　基板（２）として、１０ｍｍ×１０ｍｍ、厚さ１ｍｍの石英基板を用いた。 (Preparation of substrate)
A quartz substrate having a size of 10 mm × 10 mm and a thickness of 1 mm was used as the substrate (2).
　（酸化セリウム含有層の形成）
　ターゲットとして酸化セリウム（ＣｅＯ２）を用い、スパッタリングにより、上記基板（２）上に、層厚が１００ｎｍの酸化セリウム含有層（３）を堆積させて形成した。 (Formation of cerium oxide-containing layer)
Using cerium oxide (CeO 2 ) as a target, a cerium oxide-containing layer (3) having a layer thickness of 100 nm was deposited on the substrate (2) by sputtering.
　スパッタリングは、Ａｒガス分圧を１２０ｍＰａ、酸素ガス分圧を５０ｍＰａとし、室温（２５℃）下、５０Ｗの電力で、層厚１００ｎｍとなるように酸化セリウム（ＣｅＯ２）をＤＣパルススパッタした。ターゲット－基板間距離は、１００ｍｍであった。 Sputtering was performed by DC pulse sputtering of cerium oxide (CeO 2 ) with an Ar gas partial pressure of 120 mPa and an oxygen gas partial pressure of 50 mPa, with a power of 50 W at room temperature (25 ° C.) to a layer thickness of 100 nm. The target-substrate distance was 100 mm.
　（酸化タングステン含有層の形成）
　次いで、上記形成した酸化セリウム含有層（３）上に、上記と同様のスパッタリングにより、ターゲットとして金属タングステン（Ｗ）を用い、層厚が１００ｎｍの酸化タングステン含有層（４、ＨｘＷＯ３）を堆積した。Ａｒガス分圧を１３０ｍＰａ、酸素ガス分圧を３０ｍＰａで行った。 (Formation of a tungsten oxide-containing layer)
Next, a tungsten oxide-containing layer (4, H x WO 3 ) having a layer thickness of 100 nm is formed on the formed cerium oxide-containing layer (3) by sputtering similar to the above using metal tungsten (W) as a target. Deposited. Ar gas partial pressure was 130 mPa and oxygen gas partial pressure was 30 mPa.
　（触媒金属元素含有層の形成）
　次いで、上記形成した酸化タングステン含有層（４）上に、上記と同様のスパッタリングにより、ターゲットとして白金（Ｐｔ）を用い、層厚が１０ｎｍのＰｔから構成される触媒金属元素含有層（５）を堆積して、水素ガス検知用部材１を作製した。Ａｒガス分圧を１７０ｍＰａで行った。 (Formation of catalyst metal element-containing layer)
Next, a catalytic metal element-containing layer (5) composed of Pt having a layer thickness of 10 nm is formed on the tungsten oxide-containing layer (4) thus formed by sputtering similar to the above using platinum (Pt) as a target. The hydrogen gas detection member 1 was produced by depositing. Ar gas partial pressure was 170 mPa.
　〔水素ガス検知用部材２及び３の作製〕
　上記水素ガス検知用部材１の作製において、触媒金属元素含有層（５）の形成金属を、白金（Ｐｔ）に代えて、それぞれパラジウム（Ｐｄ）、コバルト（Ｃｏ）を用いた以外は同様にして、水素ガス検知用部材２及び３を作製した。 [Production of hydrogen gas detection members 2 and 3]
In the production of the hydrogen gas detection member 1, the formation metal of the catalyst metal element-containing layer (5) was the same except that palladium (Pd) and cobalt (Co) were used instead of platinum (Pt), respectively. Then, hydrogen gas detection members 2 and 3 were produced.
　〔水素ガス検知用部材４～６の作製〕
　上記水素ガス検知用部材１～３の作製において、酸化セリウム含有層（３）の形成を行わなかった以外は同様にして、水素ガス検知用部材４～６を作製した。 [Production of hydrogen gas detection members 4 to 6]
Hydrogen gas detection members 4 to 6 were prepared in the same manner as in the preparation of the hydrogen gas detection members 1 to 3, except that the cerium oxide-containing layer (3) was not formed.
　《水素ガス検知用部材の評価》
　下記の方法に従って、各水素ガス検知用部材の水素ガス検知能の評価を行った。 《Evaluation of hydrogen gas detection member》
According to the following method, the hydrogen gas detection ability of each hydrogen gas detection member was evaluated.
　図５Ａに記載の水素ガス検知測定装置（５０）を用いて、光透過率変化（％）を測定した。 The change in light transmittance (%) was measured using the hydrogen gas detection measuring device (50) shown in FIG. 5A.
　図５Ａに記載の水素ガス検知測定装置（５０）内に、上記作製した各水素ガス検知用部材（１）を、光源部（５１）側が基板（２）面となるように設置、固定した。 In the hydrogen gas detection and measurement apparatus (50) shown in FIG. 5A, each of the produced hydrogen gas detection members (1) was installed and fixed so that the light source part (51) side was the substrate (2) surface.
　はじめに、空気をガス流入口（５４）より水素ガス検知測定装置（５０）内に流入させ、ガス流出口（５５）より流出させながら、光源部（５１）より、可視光線（Ｌ）を照射し、波長６００ｎｍの光における空気雰囲気下での光透過率ＴＰ１（全照射光に対する光透過光の比率（％））を、分光光度計（５２）で測定した。 First, visible light (L) is irradiated from the light source part (51) while flowing air into the hydrogen gas detection measuring device (50) from the gas inlet (54) and out of the gas outlet (55). The light transmittance TP1 (the ratio (%) of light transmitted light to the total irradiated light) in an air atmosphere with light having a wavelength of 600 nm was measured with a spectrophotometer (52).
　次いで、水素ガス検知測定装置（５０）内に流入するガスを、１体積％の水素ガスを含む空気に変更させた以外は同様にして、１体積％水素ガスに暴露した時の波長６００ｎｍの光における光透過率ＴＰ２を、同じく分光光度計（５２）で測定し、上述した式（１）に従い、水素ガス濃度に対する各水素ガス検知用部材の光透過率変化（％）を測定し、これを水素ガス検知能の尺度とした。 Next, light having a wavelength of 600 nm when exposed to 1% by volume hydrogen gas in the same manner except that the gas flowing into the hydrogen gas detection / measurement device (50) is changed to air containing 1% by volume hydrogen gas. The light transmittance TP2 is measured with the spectrophotometer (52), and the change in light transmittance (%) of each hydrogen gas detecting member with respect to the hydrogen gas concentration is measured according to the above-described equation (1). A measure of hydrogen gas detection ability.
　以上により得られた結果を、表１に示す。 Table 1 shows the results obtained as described above.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に記載の結果より明らかなように、酸化セリウム含有層（３）を酸化タングステン含有層（４）の下に設け、酸化セリウムと酸化タングステンが接触する構成とした水素ガス検知用部材は、比較例に対し、水素ガスに曝された際の色変化、具体的には、淡い黄緑色の酸化タングステン（ＨｘＷＯ３）から濃い青色（タングステンブロンズ）の酸化タングステン（ＨｙＷＯ３）への変化に伴う可視光領域における光透過率の低下が大きく、水素ガスの検知感度が高いことが分かる。同一の触媒種で比較すると、Ｐｔ系では、比較例の水素ガス検知用部材４が４０％であるのに対し、本発明の水素ガス検知用部材１は１９％まで低下し、同様に、Ｐｄ系では、水素ガス検知用部材５が３９％であるのに対し、水素ガス検知用部材２は２１％まで低下し、Ｃｏ系では、水素ガス検知用部材６が６５％であるのに対し、水素ガス検知用部材３は３７％まで低下し、いずれの触媒系においても、酸化セリウム含有層を設けることにより、水素ガス検知能が大きく向上していることが分かる。 As is clear from the results shown in Table 1, the hydrogen gas detection member provided with the cerium oxide-containing layer (3) under the tungsten oxide-containing layer (4) and in which the cerium oxide and tungsten oxide are in contact with each other, Compared to the comparative example, the color change when exposed to hydrogen gas, specifically, from pale yellow-green tungsten oxide (H x WO 3 ) to dark blue (tungsten bronze) tungsten oxide (H y WO 3 ). It can be seen that the decrease in the light transmittance in the visible light region due to the change of is large, and the detection sensitivity of hydrogen gas is high. When compared with the same catalyst type, in the Pt system, the hydrogen gas detection member 4 of the comparative example is 40%, whereas the hydrogen gas detection member 1 of the present invention is reduced to 19%. In the system, the hydrogen gas detection member 5 is 39%, whereas the hydrogen gas detection member 2 is reduced to 21%. In the Co system, the hydrogen gas detection member 6 is 65%. The hydrogen gas detecting member 3 decreases to 37%, and it can be seen that the hydrogen gas detecting ability is greatly improved by providing the cerium oxide-containing layer in any catalyst system.
　実施例２
　《コア・シェル型粒子の水素ガス検知用部材の作製》
　以下の方法に従って、コア・シェル型粒子の水素ガス検知用部材１１～１５を作製した。 Example 2
《Preparation of core / shell particle hydrogen gas detection member》
In accordance with the following method, hydrogen gas detecting members 11 to 15 of core / shell type particles were produced.
　〔水素ガス検知用部材１１の作製〕
　図４に記載のコア・シェル粒子の製造工程（１００）のフローに従って、コア・シェル型粒子より構成される水素ガス検知用部材１１を作製した。なお、反応釜及び調整釜の符号と工程名は、図４に記載したものに対応している。 [Production of Hydrogen Gas Detection Member 11]
According to the flow of the manufacturing process (100) of the core / shell particles shown in FIG. 4, a hydrogen gas detection member 11 composed of core / shell particles was produced. In addition, the code | symbol and process name of a reaction kettle and an adjustment kettle respond | correspond to what was described in FIG.
　（酸化セリウム含有層より構成するコア粒子の形成）
　はじめに、反応釜（１０１）を用いる工程ａ及び添加剤の調製釜（１０５）を用いる工程ａ１に従って、酸化セリウムより構成されるコア粒子を調製した。 (Formation of core particles composed of a cerium oxide-containing layer)
First, core particles composed of cerium oxide were prepared according to step a using the reaction vessel (101) and step a1 using the additive preparation vessel (105).
　はじめに、工程ａ１の調製釜（１０５）に、０．４モル／Ｌの硝酸セリウム水溶液を５０ｍＬと、０．４モル／Ｌの硝酸水溶液を５０ｍＬ添加し、Ｎ２ガスで通気しながら、撹拌機（１０７）で２時間撹拌して混合液（１０６）を調製した。 First, 50 mL of 0.4 mol / L cerium nitrate aqueous solution and 50 mL of 0.4 mol / L nitric acid aqueous solution were added to the preparation kettle (105) of step a1, and the agitator was aerated with N 2 gas. The mixture (106) was prepared by stirring at (107) for 2 hours.
　一方、反応釜（１０１）に、母液（１０２）として、０．５モル／Ｌのアンモニア水溶液を３００ｍＬ添加し、Ｎ２ガスで通気しながら、撹拌機（１０３）で２時間撹拌した。 Meanwhile, 300 mL of a 0.5 mol / L aqueous ammonia solution as a mother liquor (102) was added to the reaction kettle (101), and the mixture was stirred with a stirrer (103) for 2 hours while being aerated with N 2 gas.
　次いで、反応釜（１０１）のアンモニア水溶液中に、送液ポンプ（１１０）を用いて、工程ａ１の調製釜（１０５）より硝酸セリウム水溶液と硝酸セリウム水溶液の混合液（１０６）を、Ｎ２ガス雰囲気下で撹拌しながら、２５分かけて、４ｍＬ／ｍｉｎの添加速度で添加して、懸濁液（１０４）を調製した。 Next, the mixed solution (106) of the cerium nitrate aqueous solution and the cerium nitrate aqueous solution from the preparation kettle (105) of step a1 is added to the aqueous ammonia solution in the reaction kettle (101) using an N 2 gas. A suspension (104) was prepared by adding at an addition rate of 4 mL / min over 25 minutes while stirring under an atmosphere.
　次いで、Ｎ２ガスを通気撹拌しながら、懸濁液を８０℃まで昇温し、その状態を３時間維持した。 Next, the suspension was heated to 80 ° C. while agitating and stirring N 2 gas, and this state was maintained for 3 hours.
　次いで、懸濁液を２５℃まで降温した後、０．４モル／Ｌの硝酸を添加してｐＨを２．０まで下げたのち、Ｎ２ガスの通気を停止して、平均粒子径が５０ｎｍの酸化セリウム粒子（コア粒子）を含む懸濁液（１０４）を調製した。 Next, the temperature of the suspension was lowered to 25 ° C., 0.4 mol / L nitric acid was added to lower the pH to 2.0, and then the N 2 gas aeration was stopped, and the average particle size was 50 nm. A suspension (104) containing cerium oxide particles (core particles) was prepared.
　（タングステン酸による第１のシェル部の形成）
　次いで、反応釜（１１１）を用いる工程ｂ及び添加剤用の２つの調製釜（１１５及び１１５ｂ）を用いる工程ｂ１に従って、上記調製した酸化セリウムより構成されるコア粒子表面に、第１のシェル層としてタングステン酸を被覆して、コア・シェル型粒子を調製した。 (Formation of the first shell portion with tungstic acid)
Next, according to step b using the reaction vessel (111) and step b1 using the two preparation vessels for additives (115 and 115b), the first shell layer is formed on the surface of the core particles composed of the cerium oxide prepared above. The core-shell type particles were prepared by coating with tungstic acid.
　はじめに、図４に示す一方の系列の調製釜（１１５）に、３．２モル／Ｌのタングステン酸ナトリウム水溶液（１１６）を５０ｍＬ準備した。また、図４には記載していないが、他方の系列の調製釜（１１５ｂ）には、３モル／Ｌの硝酸水溶液（１１６ｂ）を２５ｍＬ準備した。 First, 50 mL of 3.2 mol / L sodium tungstate aqueous solution (116) was prepared in one series of preparation kettles (115) shown in FIG. Although not shown in FIG. 4, 25 mL of 3 mol / L nitric acid aqueous solution (116b) was prepared in the other series of preparation kettles (115b).
　反応釜（１１１）に上記調製した酸化セリウム粒子（コア粒子）を含む懸濁液（１０４）を母液として貯留し、当該懸濁液（１０４）を撹拌しながら、調製釜（１１５）よりタングステン酸ナトリウム水溶液（１１６）を添加した。 The suspension (104) containing the cerium oxide particles (core particles) prepared above is stored as a mother liquor in the reaction kettle (111), and the tungstic acid is stirred from the preparation kettle (115) while stirring the suspension (104). Aqueous sodium solution (116) was added.
　次いで、同懸濁液（１０４）に、他系列の調製釜（１１５ｂ）より硝酸水溶液（１１６ｂ）を、２５分かけて添加し、ｐＨを１．０まで下げて、この状態で、２５分で３０分間撹拌して、酸化セリウム（ＣｅＯ２）がコア粒子で、その表面にタングステン酸（Ｈ２ＷＯ４）の第１のシェル部を形成した平均粒子径が１１０ｎｍの粒子を含む懸濁液（１１２、ＣｅＯ２／Ｈ２ＷＯ４懸濁液）を調製した。 Next, an aqueous nitric acid solution (116b) is added to the same suspension (104) from another series of preparation kettles (115b) over 25 minutes, and the pH is lowered to 1.0. A suspension containing particles having an average particle diameter of 110 nm, in which cerium oxide (CeO 2 ) is a core particle and a first shell portion of tungstic acid (H 2 WO 4 ) is formed on the surface after stirring for 30 minutes ( 112, CeO 2 / H 2 WO 4 suspension).
　次いで懸濁液を、遠心分離、デカンデーション法による上澄み液の排液、純水の添加の操作を５回繰り返して、洗浄処理を行った。 Next, the suspension was subjected to washing treatment by repeating centrifugation, decantation of the supernatant liquid and addition of pure water five times.
　次いで、洗浄済みの懸濁液（１１２）に純水を添加し、５質量％に仕上げた。 Next, pure water was added to the washed suspension (112) to finish 5% by mass.
　（最表面に触媒金属元素含有層の形成）
　次いで、反応釜（１２１）を用いる工程ｃ及び調製釜（１２５）を用いる工程ｃ１に従って、上記調製したコア・シェル型粒子の第１のコア部の表面に、第２のコア部として触媒金属元素含有層を担持させて、コア・シェル型粒子を調製した。 (Formation of catalytic metal element-containing layer on the outermost surface)
Then, according to the step c using the reaction kettle (121) and the step c1 using the preparation kettle (125), the catalytic metal element as the second core part is formed on the surface of the first core part of the prepared core-shell type particle. Core-shell type particles were prepared by supporting the containing layer.
　調製釜（１２５）に、１００ミリモル／ＬのＨ２ＰｔＣｌ６・６Ｈ２Ｏ水溶液（１２６）を３００ｍＬ準備した。 Preparation kettle (125), 100 mmol / L of H 2 PtCl 6 · 6H 2 O aqueous solution (126) was 300mL prepared.
　一方、反応釜（１２１）に、上記調製した５質量％のＣｅＯ２／Ｈ２ＷＯ４懸濁液（１１２）を準備した。 On the other hand, to the reaction vessel (121) was prepared CeO 2 / H 2 WO 4 suspension of 5 mass% prepared above (112).
　次いで、反応釜（１２１）の５質量％のＣｅＯ２／Ｈ２ＷＯ４懸濁液（１１２）に、送液ポンプ（１２８）を用いて、調製釜（１２５）より３００ｍＬのＨ２ＰｔＣｌ６・６Ｈ２Ｏ水溶液（１２６）を、撹拌しながら、３０分かけて添加し、Ｈ２ＷＯ４層上に触媒として白金を含む触媒金属元素含有層を厚さ２ｎｍで担持し、ＣｅＯ２／Ｈ２ＷＯ４／Ｐｔのコア／シェル粒子を含む懸濁液（１２７）を５時間撹拌して調製した。 Next, 300 mL of H 2 PtCl 6 · from the preparation kettle (125) was added to the 5 mass% CeO 2 / H 2 WO 4 suspension (112) of the reaction kettle (121) using the liquid feed pump (128). A 6H 2 O aqueous solution (126) was added with stirring over 30 minutes, and a catalytic metal element-containing layer containing platinum as a catalyst was supported on the H 2 WO 4 layer at a thickness of 2 nm. CeO 2 / H 2 A suspension (127) containing core / shell particles of WO 4 / Pt was prepared by stirring for 5 hours.
　（乾燥及び焼成処理）
　上記調製したＣｅＯ２／Ｈ２ＷＯ４／Ｐｔのコア／シェル粒子を含む懸濁液（１２７）を、エバポレーターで水を蒸発させた。 (Drying and baking treatment)
The suspension (127) containing the core / shell particles of CeO 2 / H 2 WO 4 / Pt prepared above was evaporated with an evaporator.
　次いで、水分を除いた紛体を、１００℃で３時間乾燥させた後、２００℃で１時間の焼成処理を施して、ＣｅＯ２／ＨｘＷＯ３／Ｐｔから構成される平均粒子径が１１２ｎｍのコア・シェル型粒子である水素ガス検知用部材１１を調製した。 Next, the powder from which moisture was removed was dried at 100 ° C. for 3 hours, and then subjected to a firing treatment at 200 ° C. for 1 hour to obtain an average particle diameter of 112 nm composed of CeO 2 / H x WO 3 / Pt. A hydrogen gas detection member 11 that is a core-shell type particle was prepared.
　〔水素ガス検知用部材１２の作製〕
　上記水素ガス検知用部材１１の作製において、最表面に触媒金属元素含有層の形成に用いる触媒材料として、１００ミリモル／ＬのＨ２ＰｔＣｌ６・６Ｈ２Ｏ水溶液に代えて、１００ミリモル／ＬのＰｄＣｌ２水溶液を用いた以外は同様にして、水素ガス検知用部材１２を作製した。 [Production of Hydrogen Gas Detection Member 12]
In the preparation of the hydrogen gas detecting member 11, as a catalyst material used for forming the catalytic metal element-containing layer on the outermost surface, instead of H 2 PtCl 6 · 6H 2 O aqueous solution of 100 mmol / L, 100 mmol / L A hydrogen gas detection member 12 was produced in the same manner except that a PdCl 2 aqueous solution was used.
　〔水素ガス検知用部材１３の作製〕
　上記水素ガス検知用部材１１の作製において、最表面に触媒金属元素含有層の形成に用いる触媒材料として、１００ミリモル／ＬのＨ２ＰｔＣｌ６・６Ｈ２Ｏ水溶液に代えて、１００ミリモル／ＬのＣｏ（ＮＯ３）２水溶液を用いた以外は同様にして、水素ガス検知用部材１３を作製した。 [Production of Hydrogen Gas Detection Member 13]
In the preparation of the hydrogen gas detecting member 11, as a catalyst material used for forming the catalytic metal element-containing layer on the outermost surface, instead of H 2 PtCl 6 · 6H 2 O aqueous solution of 100 mmol / L, 100 mmol / L A hydrogen gas detection member 13 was produced in the same manner except that a Co (NO 3 ) 2 aqueous solution was used.
　〔水素ガス検知用部材１４の作製〕
　上記水素ガス検知用部材１１の作製において、最表面に触媒金属元素含有層の形成に用いる触媒材料として、１００ミリモル／ＬのＨ２ＰｔＣｌ６・６Ｈ２Ｏ水溶液に代えて、１００ミリモル／ＬのＮｉ（ＮＯ３）２水溶液を用いた以外は同様にして、水素ガス検知用部材１４を作製した。 [Production of Hydrogen Gas Detection Member 14]
In the preparation of the hydrogen gas detecting member 11, as a catalyst material used for forming the catalytic metal element-containing layer on the outermost surface, instead of H 2 PtCl 6 · 6H 2 O aqueous solution of 100 mmol / L, 100 mmol / L A hydrogen gas detection member 14 was produced in the same manner except that the Ni (NO 3 ) 2 aqueous solution was used.
　〔水素ガス検知用部材１５の作製〕
　上記水素ガス検知用部材１１の作製において、最表面に触媒金属元素含有層の形成に用いる触媒材料として、１００ミリモル／ＬのＨ２ＰｔＣｌ６・６Ｈ２Ｏ水溶液に代えて、１００ミリモル／ＬのＣｕ（ＮＯ３）２水溶液を用いた以外は同様にして、水素ガス検知用部材１５を作製した。 [Production of Hydrogen Gas Detection Member 15]
In the preparation of the hydrogen gas detecting member 11, as a catalyst material used for forming the catalytic metal element-containing layer on the outermost surface, instead of H 2 PtCl 6 · 6H 2 O aqueous solution of 100 mmol / L, 100 mmol / L A hydrogen gas detection member 15 was produced in the same manner except that a Cu (NO 3 ) 2 aqueous solution was used.
　《コア・シェル型粒子の水素ガス検知用部材の評価》
　上記作製した粉末状のコア・シェル型粒子の水素ガス検知用部材を、１体積％の水素ガスを含む空気雰囲気下に暴露した結果、全ての粒子が、速やかに薄黄緑色から濃青色（タングステンブロンズ）に色相変化を生じ、水素ガス検知感度が極めて高いことを確認することができた。 << Evaluation of core / shell type particles for detecting hydrogen gas >>
As a result of exposing the above-prepared powder core-shell particle hydrogen gas detection member to an air atmosphere containing 1% by volume of hydrogen gas, all the particles were rapidly changed from light yellow green to dark blue (tungsten). Bronze) showed a hue change, and it was confirmed that the hydrogen gas detection sensitivity was extremely high.
　実施例３
　図６に記載したのと同様の構成を備える水素ガス容器設置室（６１）を用いて、水素ガス漏えいに対する水素ガス検知用部材による水素ガス検知効果を実証した。 Example 3
Using the hydrogen gas container installation chamber (61) having the same configuration as described in FIG. 6, the hydrogen gas detection effect by the hydrogen gas detection member against hydrogen gas leakage was demonstrated.
　図６に示した構成よりなる水素ガス容器設置室（６１）内に、水素ガス源として、水素ガスボンベ（Ｃ）及び水素ガスタンク（Ｄ）を配置した。 A hydrogen gas cylinder (C) and a hydrogen gas tank (D) were arranged as a hydrogen gas source in a hydrogen gas container installation chamber (61) having the configuration shown in FIG.
　そして、実施例１で作製した薄膜シート状の水素ガス検知用部材を、試験室の壁面（Ｂ）、水素ガスボンベ（Ｃ）の表面、水素ガスタンク（Ｄ）の表面に貼り付けて設置した。 Then, the hydrogen gas detection member in the form of a thin film sheet produced in Example 1 was attached to the wall surface (B) of the test chamber, the surface of the hydrogen gas cylinder (C), and the surface of the hydrogen gas tank (D).
　また、実施例２で作製したコア・シェル型粒子の水素ガス検知用部材については、バインダーを分散させて塗料とした後、水素ガス容器設置室（６１）内部の天井（Ａ）、水素ガスタンクの配管（Ｅ）、バルブ（Ｆ）、ポンプ（Ｇ）に塗装した。さらに、試験室内に、水素ガス検知用部材の色相変化を測定するための光学測定装置（６２）と、光学測定装置（６２）で入手した色相変化を監視する検知装置（６３）、光学測定装置（６２）で測定した水素ガスの漏えいによる水素ガス検知用部材の色相の変化幅が、事前に規定している閾値を超えた場合に警報を発する警報装置（６４）と、水素ガス漏れの発生源であるバルブの遮断やポンプの駆動を停止させる制御信号（６６）を送信するガス供給制御部（６５）を備える水素ガス検知システムを設置した。 In addition, for the core / shell type hydrogen gas detection member produced in Example 2, after the binder was dispersed into a paint, the ceiling (A) inside the hydrogen gas container installation chamber (61), the hydrogen gas tank Piping (E), valve (F), and pump (G) were painted. Further, an optical measurement device (62) for measuring the hue change of the hydrogen gas detection member in the test chamber, a detection device (63) for monitoring the hue change obtained by the optical measurement device (62), and the optical measurement device (62) an alarm device (64) that issues an alarm when the change in the hue of the hydrogen gas detection member due to the leakage of the hydrogen gas exceeds a predetermined threshold, and the occurrence of hydrogen gas leakage A hydrogen gas detection system including a gas supply control unit (65) for transmitting a control signal (66) for shutting off a valve serving as a source and stopping driving of a pump was installed.
　上記水素ガス検知システムにより、試験室内に、１体積％の水素ガスを含む空気雰囲気を流入させて、各水素ガス検知用部材の色相変化を観察した結果、全ての水素ガス検知用部材が速やかに薄黄緑色から濃青色（タングステンブロンズ）に色相変化と光透過率の低下を生じ、この光透過率変化や色相変化を光学測定手段である光学測定装置で検知し、瞬時にバルブの遮断やポンプの駆動停止を行うことができた。 As a result of observing the hue change of each hydrogen gas detection member by flowing an air atmosphere containing 1% by volume of hydrogen gas into the test chamber by the hydrogen gas detection system, all the hydrogen gas detection members were quickly Hue changes from light yellow green to dark blue (tungsten bronze) and light transmittance decreases, and this light transmittance change and hue change are detected by an optical measuring device that is an optical measuring means, and the valve is shut off or pumped instantaneously. It was possible to stop driving.
　本発明の水素ガス検知用部材は、水素ガス濃度に対する高い検出感度を有し、水素ガスの使用環境、例えば、水素ガスの製造工程、貯蔵時、輸送時、あるいは消費時において、水素ガスの漏えいを事前に検知し、水素ガスによる災害を未然に防止するための高感度の水素ガス検知システムとして利用することができる。 The hydrogen gas detection member of the present invention has high detection sensitivity to the hydrogen gas concentration, and leakage of hydrogen gas in the environment where the hydrogen gas is used, for example, in the production process, storage, transportation or consumption of the hydrogen gas. Can be used in advance as a highly sensitive hydrogen gas detection system for preventing disasters caused by hydrogen gas.
　１Ａ、１Ｂ、１Ｐ　水素ガス検知用部材
　２、２ａ　基板
　３　酸化セリウム含有層
　４　酸化タングステン含有層
　５　触媒金属元素含有層
　５０　水素ガス検知測定装置
　５１　光源部
　５２　分光光度計
　５４　ガス流入口
　５５　ガス流出口
　６１　水素ガス容器設置室
　６２　光学測定装置
　６３　検知装置
　６４　警報装置
　６５　水素ガス供給制御部
　６６　制御信号
　１００　コア・シェル粒子の製造工程
　１０１、１１１、１２１　反応釜
　１０２　母液
　１０３、１０７　撹拌機
　１０４、１１２、１２７　懸濁液
　１０５、１１５、１１５ｂ、１２５　調製釜
　１０６　混合液
　１０８、１１８、１１８ｂ、１２８　送液ポンプ
　１３１　濾過・固液分離・洗浄装置
　１４１　焼成装置
　Ａ　天井
　Ｂ　壁面
　Ｃ　水素ガスボンベ
　Ｄ　水素ガスタンク
　Ｅ　配管
　Ｆ　バルブ
　Ｇ　ポンプ
　Ｇｂ　結晶粒界
　Ｌ　可視光線 1A, 1B, 1P Hydrogen gas detection member 2, 2a Substrate 3 Cerium oxide-containing layer 4 Tungsten oxide-containing layer 5 Catalytic metal element-containing layer 50 Hydrogen gas detection and measurement device 51 Light source section 52 Spectrophotometer 54 Gas inlet 55 Gas flow Outlet 61 Hydrogen gas container installation chamber 62 Optical measuring device 63 Detection device 64 Alarm device 65 Hydrogen gas supply control unit 66 Control signal 100 Core / shell particle manufacturing process 101, 111, 121 Reactor 102 Mother liquid 103, 107 Stirrer 104, 112, 127 Suspension 105, 115, 115b, 125 Preparation kettle 106 Mixed solution 108, 118, 118b, 128 Liquid feed pump 131 Filtration / solid-liquid separation / cleaning device 141 Firing device A Ceiling B Wall surface C Hydrogen gas cylinder D Hydrogen gas tank E Piping F Valve G Pump Gb Grain boundary L Visible Line

Claims (10)

  1. 　酸化セリウム含有層、酸化タングステン含有層、及び触媒金属元素含有層を備え、
    　前記酸化セリウム含有層と前記酸化タングステン含有層とが隣接して配置され、前記触媒金属元素含有層が、前記酸化タングステン含有層の、前記酸化セリウム含有層に対向する面とは反対側に配置され、
    　水素ガス濃度変化に応じて、光吸収特性が変化することを特徴とする水素ガス検知用部材。     A cerium oxide-containing layer, a tungsten oxide-containing layer, and a catalytic metal element-containing layer,
    The cerium oxide-containing layer and the tungsten oxide-containing layer are disposed adjacent to each other, and the catalytic metal element-containing layer is disposed on the opposite side of the surface of the tungsten oxide-containing layer that faces the cerium oxide-containing layer. ,
    A member for detecting hydrogen gas, wherein light absorption characteristics change according to a change in hydrogen gas concentration.
  2. 　前記触媒金属元素含有層が、白金、パラジウム、ロジウム、イリジウム、ルテニウム、オスミウム、コバルト、ニッケル及び銅から選ばれる金属元素を含有することを特徴とする請求項１に記載の水素ガス検知用部材。 2. The hydrogen gas detection member according to claim 1, wherein the catalytic metal element-containing layer contains a metal element selected from platinum, palladium, rhodium, iridium, ruthenium, osmium, cobalt, nickel and copper.
  3. 　前記触媒金属元素含有層が、白金、パラジウム、コバルト、ニッケル、又は銅を含有することを特徴とする請求項１又は請求項２に記載の水素ガス検知用部材。 3. The hydrogen gas detection member according to claim 1, wherein the catalytic metal element-containing layer contains platinum, palladium, cobalt, nickel, or copper.
  4. 　前記酸化セリウム含有層、酸化タングステン含有層、及び触媒金属元素含有層より構成される水素ガス検知用部材が、薄膜シート状であることを特徴とする請求項１から請求項３までのいずれか一項に記載の水素ガス検知用部材。 The hydrogen gas detection member composed of the cerium oxide-containing layer, the tungsten oxide-containing layer, and the catalytic metal element-containing layer is in the form of a thin film sheet. The hydrogen gas detection member according to item.
  5. 　前記酸化セリウム含有層、酸化タングステン含有層、及び触媒金属元素含有層より構成される水素ガス検知用部材が粒子状であり、前記触媒金属元素含有層が前記酸化タングステン含有層より外側にあることを特徴とする請求項１から請求項３までのいずれか一項に記載の水素ガス検知用部材。 The hydrogen gas detection member composed of the cerium oxide-containing layer, the tungsten oxide-containing layer, and the catalytic metal element-containing layer is in the form of particles, and the catalytic metal element-containing layer is outside the tungsten oxide-containing layer. The hydrogen gas detection member according to any one of claims 1 to 3, wherein the member is a hydrogen gas detection member.
  6. 　前記粒子状の水素ガス検知用部材が、３層よりなるコア・シェル構造を有し、コア部が酸化セリウム含有層で構成され、シェル部が酸化タングステン含有層及び触媒金属元素含有層で構成され、前記酸化セリウム含有層と前記酸化タングステン含有層とが接触している構造を有していることを特徴とする請求項５に記載の水素ガス検知用部材。 The particulate hydrogen gas detection member has a core-shell structure consisting of three layers, the core part is composed of a cerium oxide-containing layer, and the shell part is composed of a tungsten oxide-containing layer and a catalytic metal element-containing layer. 6. The hydrogen gas detection member according to claim 5, wherein the cerium oxide-containing layer and the tungsten oxide-containing layer are in contact with each other.
  7. 　請求項１から請求項４までのいずれか一項に記載の水素ガス検知用部材を製造する水素ガス検知用部材の製造方法であって、
    　酸化セリウム含有層と酸化タングステン含有層とを隣接して配置し、
    　前記酸化タングステン含有層の、前記酸化セリウム含有層に対向する面とは反対側に、触媒金属元素含有層を配置する、
    　ことを特徴とする水素ガス検知用部材の製造方法。     A method for producing a hydrogen gas detection member for producing the hydrogen gas detection member according to any one of claims 1 to 4,
    A cerium oxide-containing layer and a tungsten oxide-containing layer are disposed adjacent to each other;
    Disposing a catalytic metal element-containing layer on the opposite side of the tungsten oxide-containing layer from the surface facing the cerium oxide-containing layer;
    A method for producing a hydrogen gas detection member.
  8. 　請求項５又は請求項６に記載の水素ガス検知用部材を製造する水素ガス検知用部材の製造方法であって、
    　酸化セリウムを含有するコア粒子を形成し、
    　前記コア粒子上に、酸化タングステンを含有する第１のシェル部を形成し、
    　前記第１のシェル部上に触媒金属元素を含む第２のシェル部を形成する、
    　ことを特徴とする水素ガス検知用部材の製造方法。     A method for producing a hydrogen gas detection member for producing the hydrogen gas detection member according to claim 5 or 6,
    Forming core particles containing cerium oxide,
    Forming a first shell portion containing tungsten oxide on the core particles;
    Forming a second shell portion containing a catalytic metal element on the first shell portion;
    A method for producing a hydrogen gas detection member.
  9. 　請求項１から請求項６までのいずれか一項に記載の水素ガス検知用部材と、
    　当該水素ガス検知用部材に特定の波長を照射する光源部と、
    　前記水素ガス検知用部材を通過した光を測定する光学測定装置と、
    　前記光学測定装置で測定した光吸収特性が規定値を超えるか否かを検知する検知装置と、
    　前記検知装置が検知する情報に基づき警報を発する警報装置と、
    　を備えることを特徴とする水素ガス検知システム。     The hydrogen gas detection member according to any one of claims 1 to 6,
    A light source unit for irradiating the hydrogen gas detection member with a specific wavelength;
    An optical measuring device for measuring the light passing through the hydrogen gas detecting member;
    A detection device for detecting whether or not the light absorption characteristic measured by the optical measurement device exceeds a specified value;
    An alarm device that issues an alarm based on information detected by the detection device; and
    A hydrogen gas detection system comprising:
  10. 　前記検知装置の検出する情報に基づき、水素ガスの供給を遮断するガス供給制御部をさらに備えることを特徴とする請求項９に記載の水素ガス検知システム。 The hydrogen gas detection system according to claim 9, further comprising a gas supply control unit that cuts off the supply of hydrogen gas based on information detected by the detection device.
PCT/JP2016/051200 2015-03-06 2016-01-18 Hydrogen gas detecting member, method for manufacturing same, and hydrogen gas detecting system WO2016143385A1 (en)

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JP3192325U (en) * 2014-05-28 2014-08-07 功 村上 Optical hydrogen gas detection switch
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JPH1010039A (en) * 1996-06-24 1998-01-16 Dkk Corp Beam splitter, and absorbance measuring device using this beam splitter
JP2007057233A (en) * 2005-08-22 2007-03-08 Hitachi Cable Ltd Optical gas sensor
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