WO2007142148A1 - Catalyst contained inside porous carbon layer and method for producing the same - Google Patents

Catalyst contained inside porous carbon layer and method for producing the same Download PDF

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Publication number
WO2007142148A1
WO2007142148A1 PCT/JP2007/061207 JP2007061207W WO2007142148A1 WO 2007142148 A1 WO2007142148 A1 WO 2007142148A1 JP 2007061207 W JP2007061207 W JP 2007061207W WO 2007142148 A1 WO2007142148 A1 WO 2007142148A1
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WIPO (PCT)
Prior art keywords
layer
silica
catalyst
porous
containing layer
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PCT/JP2007/061207
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French (fr)
Japanese (ja)
Inventor
Shigeru Ikeda
Susumu Kuwabata
Tsukasa Torimoto
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Osaka University
National University Corporation Nagoya University
Juridical Foundation Osaka Industrial Promotion Organization
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Application filed by Osaka University, National University Corporation Nagoya University, Juridical Foundation Osaka Industrial Promotion Organization filed Critical Osaka University
Priority to JP2008520541A priority Critical patent/JP4584334B2/en
Publication of WO2007142148A1 publication Critical patent/WO2007142148A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • B01J37/082—Decomposition and pyrolysis
    • B01J37/084—Decomposition of carbon-containing compounds into carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • B01J21/08—Silica
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/18—Carbon
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • B01J37/0018—Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)
    • B01J35/51—

Definitions

  • the present invention relates to a catalyst that lowers activation energy and promotes a reaction.
  • Patent Document 1 employs a method in which the surface of the nanoparticles is directly coated with a porous substance made of an inorganic oxide, thereby preventing aggregation of the nanoparticles. (Patent Document 1).
  • Patent Document 1 Japanese Patent Laid-Open No. 2005-276688
  • Patent Document 1 in which a porous material such as an inorganic oxide is directly applied to the surface of the nanoparticles (patent document 1), although separation and recovery of the catalyst nanoparticles are easy, Since the surface of the nanoparticle is directly covered with porous ceramics, the active sites on the surface of the nanoparticle are reduced, and the catalytic function expected to be inherently possessed by the nanoparticle cannot be expressed. There was a problem.
  • the present invention has been made in view of the above, and an object of the present invention is to provide a nanoparticle catalyst that maintains a high catalytic activity and that can be easily separated and recovered, and a method for producing the same. There is.
  • a catalyst having a core part containing a catalyst and a porous layer formed so as to cover the core part includes a core part and a porous layer.
  • the present invention provides a catalyst comprising a core part containing catalyst particles and a porous carbon layer formed so as to cover the core part, and the core part and the porous carbon layer In the meantime, a hollow layer is provided, and the hollow layer is in the catalyst formed by removing the SiO-containing layer formed between the core part and the porous carbon layer.
  • the present invention also relates to a method for producing a catalyst including a core part including catalyst particles and a porous carbon layer formed so as to cover the core part, the SiO containing so as to cover the core part.
  • porous S is formed on the SiO-containing layer covering the core.
  • porous carbon layer by carbonizing the carbon source. This is because the porous carbon layer can be made finer.
  • SiO contained in the iO-containing layer for example, among hydrofluoric acid solution and alkaline solution
  • the catalyst nanoparticle means that the core portion including the catalyst particle is 0.5 ⁇ ! It shall mean a catalyst having a diameter of ⁇ 500 nm.
  • the invention's effect [0010] Since the hollow layer is provided between the core portion and the porous carbon layer, the active site of the catalyst is not reduced, and a high catalytic function is obtained. Furthermore, since the catalyst is covered with a porous carbon layer, when metal nanoparticles are used as a catalyst, the nanoparticles can be prevented from agglomerating and the catalytic activity can be maintained high. In addition, since the core portion including the nanoparticles is covered with the porous carbon layer, the nanoparticles can be easily reused as a catalyst after being separated and collected.
  • nanoparticle catalyst that maintains a high catalytic activity and that can be easily separated and recovered and a method for producing the same.
  • FIG. 1 is a cross-sectional view of a catalyst encapsulated in a porous carbon layer produced by the production method according to the present invention.
  • FIG. 2 is a perspective view of the catalyst with a part of the porous carbon layer removed.
  • FIG. 3a is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
  • FIG. 3b is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
  • FIG. 3c is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
  • Fig. 3d is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
  • FIG. 3e is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
  • FIG. 4 is a TEM photograph of a Pt catalyst (Pt—mhC) encapsulated in a hollow porous carbon layer.
  • FIG. 5 is a graph showing the conversion efficiency by catalyst.
  • Fig. 6 is a result of an electrocatalytic reaction of a Pt catalyst encapsulated in a hollow porous carbon layer.
  • Figure 7 shows a TEM photograph of Rh catalyst (Rh—mhC) encapsulated in a hollow porous carbon layer. It is.
  • FIG. 8 is a TEM photograph of a Pd catalyst (Pd—mhC) encapsulated in a hollow porous carbon layer.
  • FIG. 9 is a TEM photograph of a Ru catalyst (Ru-mhC) encapsulated in a hollow porous carbon layer.
  • FIG. 10 is a TEM photograph of Au catalyst (Au—mhC) encapsulated in a hollow porous carbon layer.
  • FIG. 1 is a cross-sectional view of a catalyst encapsulated in a porous carbon layer produced by the production method according to the present invention
  • FIG. 2 is a perspective view of the catalyst with a part of the porous carbon layer 3 ′ removed.
  • the catalyst includes a core part 1 containing catalyst particles, and a porous carbon layer 3 ′ that covers the core part 1 with a space therebetween, and the core part 1 and the porous carbon layer 3 A hollow layer 2 'is interposed between them.
  • the porous carbon layer 3 ′ is made of carbon or contains carbon, and the portion made of carbon has a porous structure made of developed pores.
  • the porous carbon layer 3 ' is composed of a porous structure, a solution that is catalyzed
  • the iso-reactive substance penetrates into the porous carbon layer 3 ′ with the porous tissue force and contacts the core part 1 containing the catalyst particles to be catalyzed.
  • the core portion 1 containing the catalyst particles is not directly covered with the porous body, and the core portion 1 is formed by interposing the hollow layer 2 ′ between the core portion 1 and the porous carbon layer 3 ′. Since it is covered with the porous carbon layer 3, the active sites of the catalyst particles contained in the core portion 1 are exposed, and the catalytic activity can be kept high. In general, nano-order sized catalyst particles aggregate to reduce the catalytic action.
  • the core portion 1 containing the catalyst particles is covered with the porous carbon layer 3 ′, the core portion There is no risk of aggregation between them. Therefore, the activity of the catalyst can be kept high.
  • a method for producing a catalyst according to a preferred embodiment of the present invention includes: 1. a step of preparing a core portion containing catalyst particles (a preparation step of a core portion); (Silica-containing layer forming step); 3. directly covering the silica-containing layer with the porous silica-containing layer (porous silica-containing layer forming step); and 4. carbon source in the porous silica-containing layer. Filling process (carbon source filling process), 5. carbon source carbonization to form a porous carbon layer (carbonization process), and 6. inclusion in silica-containing layer and porous silica-containing layer And a step of dissolving and removing the silica (silicic force dissolution / removal step), and optionally 7. a step of post-treating the catalyst (post-treatment step).
  • the core portion 1 is prepared (FIG. 3a).
  • the core 1 can be nanoscale catalyst particles or sub-micrometer catalyst particles of several nanometers.
  • nanoscale catalyst particles and metal ions may be dispersed in nanoscale spheres using oxide catalyst particles as a support, or nanoscale catalyst particles themselves may be used as core portion 1.
  • the method for producing the catalyst or the catalyst nanoparticles forming the core part 1 is not particularly limited, but can be produced by an impregnation method, a liquid phase reduction method, or the like.
  • the core part 1 When the core part 1 is produced by the impregnation method, it is necessary or necessary to immerse the carrier in a solution in which a metal salt is dissolved under a metal nanoparticle or metal ion serving as a catalyst and dry it.
  • the dried particles can be reduced by the following liquid phase reduction or H gas.
  • a core part 1 in which catalyst nanoparticles in the range of ⁇ 5 nm and a catalyst having a metal ion force are dispersed can be obtained.
  • core part 1 is prepared by a liquid phase reduction method, alcohol or hydrogenation is applied to the catalyst metal raw material dissolved in a solution containing a protective agent such as a polymer or the catalyst metal raw material dispersed in the support by the impregnation method.
  • a reducing agent such as potassium borohydride, sodium borohydride, hydrazine, it is possible to obtain the core 1 composed of metal nanoparticles or a carrier in which metal nanoparticles are dispersed.
  • a silica-containing layer (first layer) 2 that becomes a hollow layer is formed on the surface of the single nanoscale core portion 1 obtained as described above.
  • Figure 3b shows the core 1 directly coated with a silica-containing layer.
  • the core part 1 and a precursor of the silica-containing layer for example, tetraethoxysilane (TEOS), are mixed in a solution, and TEOS is hydrolyzed and subjected to a dehydration condensation reaction.
  • TEOS tetraethoxysilane
  • TEOS tetraethoxysilane, Si (OCH 2 CH 3)
  • Si Si (OCH 2 CH 3)
  • a silica-containing layer is formed on the surface of the core part 1 by the above reaction (reaction formulas C and D) (FIG. 3b).
  • the silica-containing layer thus formed is a layer containing almost no pores, and becomes a hollow layer 2 ′ by removing SiO with a solution capable of dissolving and removing, as described later.
  • the porous silica-containing layer 3 is formed on the silica-containing layer 2.
  • the material constituting the porous silica-containing layer 3 is preferably the same as the material constituting the silica-containing layer 2. This is because they can be dissolved and removed simultaneously with the same solution.
  • the catalyst particles coated with the silica-containing layer are suspended, for example, in a solution containing tetraethoxysilane (silicon alkoxide containing one or more TEO groups), and these silicon alkoxides are hydrolyzed and subjected to dehydration condensation reaction.
  • the surface of the silica-containing layer 2 is covered with a silica layer containing an alkyl group (a layer that becomes the porous silica-containing layer 3), specifically, TEOS (Si (OC H )) To produce Si (OH)
  • a layer that becomes a porous silica-containing layer is formed on the surface of the silica-containing layer by the above reaction (reaction formulas E, F, and G) (FIG. 3c).
  • this is heat-treated to decompose and remove the octadecyl group contained in the layer that becomes the porous silica-containing layer, so that the decomposed and removed octadecyl group portion becomes pores, and the porous silica-containing layer 3 is formed.
  • the alkyl group contained in the silicon alkoxide that forms the porous silica-containing layer 3 is an alkyl group that may be two or more in the molecule, which may be linear or branched. It may contain a functional group or the like at the end or in the middle.
  • Typical examples of linear or branched alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, isoamyl, and hexyl.
  • porous silica-containing layer 3 only silicon alkoxide (for example, ODTS) containing one or more of these alkyl groups is hydrolyzed without adding alkoxysilane such as tetraethoxysilane (TEOS). 'After dehydrating and condensing, heat treatment may be performed. However, it is preferable to carry out hydrolysis and dehydrating and condensing reaction by adding TEOS to ODTS in order to form a porous layer completely.
  • TEOS tetraethoxysilane
  • alkoxysilane examples include tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), and tetrabutoxysilane (TBOS).
  • TMOS tetramethoxysilane
  • TEOS tetraethoxysilane
  • TBOS tetrabutoxysilane
  • a carbon source such as phenol resin, polyacrylamide, polypyrrole or the like is dissolved in a solvent such as ethanol or methanol.
  • a solvent such as ethanol or methanol.
  • innumerable pores formed in the porous silica layer 3 are impregnated with a solvent containing the coconut resin.
  • the pores may be filled by filling the innumerable pores with the above-mentioned resin or polymer force, glucose, sucrose, furfuryl alcohol, pyrrole, etc., and polymerizing them in the pores.
  • Guphenol and formaldehyde may be polycondensed in the pores and filled with phenol resin. Further, instead of these, cheaper petroleum pitches may be filled in the pores.
  • the precursor containing these carbon sources is calcined by calcining at 300 ° C. to 900 ° C., more preferably at 600 ° C. to 800 ° C.
  • the catalyst coated with the layer that becomes the porous silica-containing layer 3 via the silica-containing layer 2 is immersed in a solution capable of dissolving SiO, thereby obtaining a porous material.
  • the porous carbon layer 3 ′ is a porous silica-containing layer 3 made of SiO.
  • Examples include alkaline solutions such as solutions and KOH solutions.
  • the core portion 1 also has catalyst particle force or includes catalyst particles, and is covered with a porous carbon layer 3 with a hollow layer 2 therebetween.
  • the core part 1 actually acts on the reactants.
  • iron (Fe), ruthenium (Ru), conol (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt ), Gold (Au), copper (Cu), and silver (Ag) are preferably included as catalyst particles.
  • the catalyst particles may be in various forms such as a single body, an alloy, an ion, or an inorganic salt.
  • the core portion 1 may have any shape as long as the catalyst function can be satisfactorily exhibited.
  • the core part 1 itself forms catalyst particles, which are substantially spherical, the diameter is 0.5 ⁇ ! It is preferably in the range of ⁇ 5 nm, and more preferably in the range of 0.5 nm to 2 nm.
  • the catalyst particles having such a size exhibit high catalytic activity because the number of exposed atoms used for catalysis among the atoms constituting the catalyst particles is 50% or more of the total number of atoms.
  • the core portion 1 only needs to contain catalyst particles in part.
  • the diameter of the core part 1 is preferably in the range of 0.5 nm to 500 nm, and more preferably in the range of 0.5 nm to 100 nm.
  • the core portion 1 may include catalyst particles in the surface layer portion, for example. This is because if only the surface layer of the core part has a catalyst particle force, the atom utilization efficiency of the catalyst is improved and the active site can be used effectively.
  • the core part 1 is integrally formed, one of which is confined in the porous carbon layer 3 ', but there are a plurality of core parts 1 in the porous carbon layer 3'. You may do it. If a plurality of the catalyst particles are present and the metal content is increased, the catalyst can be used as a fuel cell catalyst (for example, an anode (oxygen reduction side) of a polymer electrolyte fuel cell). In the polymer electrolyte fuel cell, the superporous shell structure can facilitate access to oxygen metal (Pt) and discharge of generated water.
  • a fuel cell catalyst for example, an anode (oxygen reduction side) of a polymer electrolyte fuel cell.
  • the superporous shell structure can facilitate access to oxygen metal (Pt) and discharge of generated water.
  • the core portion 1 may be hollow. Furthermore, the core part 1 may have a porous structure at least in part, and the porous structure itself may serve as a catalyst.
  • a catalyst include zeolite (Si—O—Ai—O—Si), niobic acid, polyacid, and the like.
  • zeolite is an aluminosilicate having fine pores in the crystal
  • niobic acid is an oxide of metallic niobium (heavy metal).
  • polyacids refer to transition metal ions such as vanadium (V 5+ ), niobium (Nb 5+ ), molybdenum (Mo 6+ ), tungsten (W 6+ ), tantalum (Ta 5+ ) o emissions (o 2_)
  • certain Okiso acid formed by coordinated by refers to a polymerized compound of a plurality of Okiso acid different kind.
  • the element that forms the central oxo acid is called a hetero element, and the oxo acid element that polymerizes around it is called a poly element, and the hetero elements include Si, P, As, S, Fe, Co, etc. Mo, W, V, Nb, Ta, etc. are used.
  • the core part 1 has a porous structure itself such as zeolite
  • the size of the core part 1 is not limited to the nanoscale, and may have a size of several tens / zm to several tens of mm.
  • fine catalyst particles may be dispersed in the fine pores of such a porous structure.
  • the porous layer covering the catalyst is made of carbon. Due to the carbon structure of the porous layer, it has a high affinity for reactants that are generally hydrophobic, so that the reactants are effectively trapped (concentration effect) and effectively on the catalyst particle surface. Supplied. In addition, since the carbon layer can be removed simply by heat treatment, the catalyst metal can be easily recovered and recycled.
  • the porous carbon layer 3 ′ has a force that covers the core part 1 containing the catalyst particles via the hollow layer 2 ′.
  • the hollow layer 2 ′ is interposed between the core portion 1 and the porous carbon layer 3 ′, the active site is not killed and good catalytic action can be exhibited.
  • the porous carbon layer 3 ' is hollow and includes a porous structure in at least a part of the porous carbon layer 3'.
  • This porous structure includes, at least in part, micropores communicating with the porous carbon layer 3 ′ and the external force hollow layer 2.
  • the shape of the porous carbon layer 3 ' is not limited to a spherical shape, and may be any shape as long as the same effect as described above is obtained.
  • the diameter of the porous carbon layer 3 'is' ⁇ ! ⁇ 1 ⁇ m is preferred. This is because of the ease of catalyst recovery.
  • the diameter of the micropores of the porous carbon layer 3 ' is large enough to allow contaminants, odors, sewage, microorganisms, etc. to pass through from outside the porous carbon layer 3' and the core portion 1 does not flow out. Any size is acceptable.
  • the pore diameter of the fine pores of the porous carbon layer 3 ′ may be any size as long as it is smaller than the diameter of the core part 1 encapsulated by the porous carbon layer 3 ′, but is 0.3 nm to 10 nm. It is more preferable that the thickness is 0.5 nm to lnm. If the pore size is 0.5 nm or more, even an aromatic organic compound can pass through the pores and reach the catalyst active point. This is because if the pore diameter is 1 nm or less, the core part does not flow out completely.
  • the thickness of the porous carbon layer 3 ' is the same as described above, and allows contaminants, odors, sewage, microorganisms, etc. to pass from the outside of the porous carbon layer 3', and the porous carbon layer 3 'itself is durable. As long as it has, any size may be used. Considering the above conditions, the thickness of the porous carbon layer 3 ′ is preferably in the range of lOnm to 1 ⁇ m.
  • the catalyst encapsulated in the porous carbon layer according to the present invention can be easily separated from the reaction solution by filtering with a filter paper or the like after completion of the catalytic reaction.
  • the reaction solution may be separated by sedimentation by centrifugation.
  • the dried and recovered catalyst can be reused as it is, or can be reused by performing an activation treatment as necessary.
  • the carbon content of the porous carbon layer can be decomposed and removed by heat treatment. It can be easily recovered.
  • the catalyst production method is as follows: 1. A step of preparing a core part containing catalyst particles (preparation step of core part); 2. A step of directly covering the surface of the core part with a silica-containing layer (silica-containing layer forming step) 3) A step of forming a porous silica-containing layer on the silica-containing layer using a pore-forming agent (a porous silica-containing layer forming step); and 4. A carbon source is filled in the porous silica-containing layer. A step of carbonization (carbon source filling step), 5. a step of carbonizing the carbon source to form a porous carbon layer (carbonization step), and 6.
  • a silica-containing layer and a silica contained in the porous silica-containing layer includes a step of dissolution and removal (silica dissolution / removal step) and, if necessary, 7. a step of post-treating the catalyst (post-treatment step)! Explanation of the same steps as those in Embodiment 1 is omitted.
  • the silica-containing layer-coated catalyst prepared in the silica-containing layer forming step and the pore-forming agent are used as a solvent.
  • a suspension solution To prepare a suspension solution.
  • the pore forming agent is dispersed in the solvent.
  • the pore-forming agent has a saddle shape for forming pores.
  • examples of such a pore-forming agent include surfactants and water-soluble polymers.
  • a surfactant when a surfactant is used as the pore forming agent, it is dispersed as micelles in the above suspension solution.
  • a cationic surfactant is particularly preferably used.
  • the surfactant As the surfactant, it,
  • R to R are methyl groups or linear alkyl groups
  • cetyltrimethylammonium bromide cetyltrimethylammonium bromide, octyltrimethylammonium bromide, decyltrimethylammonium bromide, dodecyltrimethylaluminumbromide, tetradecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, cetyltrimethylammonium chloride, octyl Examples thereof include trimethylammonium chloride, decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, and octadecyltrimethylammonium chloride. Cetyltrimethyl ammonium bromide (CT AB) is preferred.
  • Water is used as a solvent in which the silica-containing layer-coated catalyst particles and the pore-forming agent are mixed.
  • a precursor of the porous silica layer for example, tetraethoxysilane (TEOS) is mixed into the suspension solution containing the catalyst particles coated with the silica-containing layer 2 ′.
  • TEOS tetraethoxysilane
  • FIG. 3d a laminar force silica-containing layer 2 that becomes the porous silica layer 3 is formed.
  • the porous silica-containing layer 3 is formed by hydrolysis and dehydration condensation of TEOS. Concrete Specifically, according to the above formula C, TEOS (Si (OC H)) is hydrolyzed to produce Si (OH)
  • the layer that becomes the porous silica-containing layer grows while taking in micelles that also have surfactant power. For this reason, micelles are dispersed in the layer that becomes the porous silica-containing layer, and if these micelles disappear, they become pores. Therefore, the pore diameter of the porous silica-containing layer 3 of the catalyst according to the final product can be adjusted by adjusting the chain length of the hydrophobic group of the surfactant. Further, it is possible to adjust the porosity of the porous layer 4 by adjusting the concentration of the pore forming agent.
  • the step of mixing the pore-forming agent and the step of forming the porous layer are preferably performed under basic conditions. This is because in the basicity, the dehydration condensation reaction proceeds at an appropriate speed, and as a result, a good porous layer can be obtained.
  • a catalyst encapsulating Pt nanoparticles was produced by the method for producing a catalyst encapsulated in a porous carbon layer according to the present invention.
  • Pt-PVP represents a material coated with Pt particle force PVP.
  • Pt catalyst coated with SiO 2 was referred to as Pt—SiO 2.
  • FIG. 4 shows a TEM photograph of Pt—mhC. From FIG. 4, it is confirmed that a hollow layer is formed between the porous carbon layer and the Pt nanoparticles as the core part.
  • the specific surface area and average pore diameter of the catalyst encapsulated in the porous carbon layer produced as described above were measured.
  • the specific surface area was measured by the specific surface area measurement method (BET method).
  • the average pore size was analyzed by the pore size distribution measurement method (BJH method).
  • the specific surface area of the porous carbon layer of the nanoparticle catalyst was 639 [mV g], and the average pore diameter was 2. lnm.
  • Nitrobenzene is dissolved in ethanol and H gas is supplied at a rate of 20mlZmin.
  • a three-electrode cell was used for the electrochemical measurement, a glassy carbon with a catalyst on the working electrode, platinum as the counter electrode, and silver (salt) ⁇ silver as the reference electrode. The potential difference of was reduced).
  • As the electrolyte solution 0.1MHC10 was used. The reduction reaction of O is
  • Rh-PVP having an average particle diameter of 2.5 nm (Rh-PVP means that Rh particles are coated with PVP) was obtained.
  • Rh catalyst coated with SiO 2 Rh catalyst coated with SiO 2
  • the medium is represented as Rh—SiO. )was gotten.
  • Rh catalyst Rh—mhC
  • Figure 7 shows a TEM photograph of Rh-mhC. From FIG. 7, it was confirmed that a hollow layer was formed between the porous carbon layer and the Rh nanoparticles as the core.
  • Rh nanoparticle catalyst 0.25 mol was mixed with a solution containing toluene, and 0.6 M Pa H gas was supplied thereto, and the reaction was performed at 75 ° C. for 3 hours.
  • decane was used as the solvent.
  • Rh / C * 22.9 156
  • Rh nanoparticles encapsulated in the porous carbon layer according to the present invention have a reaction efficiency higher than that of the raw material Rh-PVP and activated carbon-supported Rh catalyst (RhZC *). I found that it was more than twice as high.
  • Rh-PVP H 2 0 60 1.1 15
  • Rh nanoparticles encapsulated in the porous carbon layer according to the present invention is higher than that of Rh-PVP and activated carbon supported Rh catalyst (RhZC). I found that it was more than twice as high. Moreover, it was confirmed that even when water was used as a solvent, a superior reactivity was exhibited.
  • Pd—PVP having an average particle diameter of 1.3 nm Pd—PVP means that Pd particles are coated with PVP was obtained.
  • SiO 2 silica layer
  • the coated Pd catalyst is expressed as Pd-SiO. )was gotten.
  • a porous carbon layer was formed as described above. From this, a Pd catalyst (Pd-mhC) encapsulated in a hollow porous carbon layer was produced.
  • Fig. 8 shows a TEM photograph of Pd-mhC. As shown in Fig. 8, it was confirmed that a hollow layer was formed between the porous carbon layer and the Pd nanoparticles as the core.
  • Ru—PVP having an average particle diameter of 2 nm (Ru PVP represents a Ru particle coated with PVP) was obtained.
  • the surface of the silica layer is coated with a silica layer containing an alkyl group (octadecyl group) by stirring a mixed solution of 5 mL (120 mmol), TEOS 0.4 mL (l. 76 mmol) and ODTS 0.16 mL at room temperature for 2 hours. did. 70 mL of toluene was added to this solution and centrifuged at 3000 rpm for 10 minutes, and the residue was dried at 80 ° C. Thereafter, this was further calcined at 550 ° C. for 4 hours in a nitrogen atmosphere.
  • an alkyl group octadecyl group
  • chloroplatinic acid H PtCl
  • HuCl chloroplatinic acid
  • Au-PVP having m Au-PVP represents Au particles coated with PVP
  • Au-SiO A covered Au catalyst (hereinafter, the Au catalyst coated with SiO is referred to as Au-SiO) is obtained.

Abstract

Disclosed is a method for producing a catalyst having high catalytic activity which can be easily separated/recovered. Specifically disclosed is a method for producing a catalyst comprising a core portion containing catalyst particles and a porous carbon layer which is so formed as to cover the core portion. In this method, a silica-containing layer is formed to cover the core portion, and a porous silica-containing layer is formed to cover the silica-containing layer. Then, after filling at least a part of the porous silica-containing layer with a carbon source, the carbon source is carbonized, thereby forming the porous carbon layer and removing the silica-containing layer.

Description

明 細 書  Specification
多孔質炭素層に内包された触媒及びその製造方法  Catalyst encapsulated in porous carbon layer and method for producing the same
技術分野  Technical field
[0001] 本発明は、活性化エネルギーを低下させ反応を促進する触媒に関する。  The present invention relates to a catalyst that lowers activation energy and promotes a reaction.
背景技術  Background art
[0002] 現在、粒子を数ナノオーダーまで超微粒子化することにより、ノ レク状態と全く異な る化学的、物理的、電気的、光学的、磁気的並びに機械的特性を発現しうることが明 らかになつてきた。触媒粒子においても、その直径を数 nmオーダーに近づけると、こ のような特性の変化や触媒活性点の増大により、高い触媒活性を示すことが明らか になってきている。しかし、粒径が数 nmオーダーである粒子は、表面エネルギーが 非常に大きく分散不安定であり、そのまま触媒として使用できない。  [0002] At present, it is clear that chemical, physical, electrical, optical, magnetic, and mechanical properties that are completely different from the normal state can be expressed by making particles ultra-fine to the order of several nanometers. It has been easy. It has become clear that catalyst particles exhibit high catalytic activity due to such changes in characteristics and increased catalytic activity points when the diameter of catalyst particles approaches several nanometers. However, particles with a particle size on the order of several nm have a very large surface energy and are unstable in dispersion, and cannot be used as a catalyst as they are.
[0003] そのため、ナノ粒子をポリマー'デンドリマー等で保護することにより、ナノ粒子の凝 集を防止することが試みられて 、る。  [0003] Therefore, attempts have been made to prevent aggregation of nanoparticles by protecting the nanoparticles with a polymer dendrimer or the like.
[0004] また、特許文献 1にお 、ては、ナノ粒子の表面を、無機酸ィ匕物からなる多孔性物質 で直接被覆する方法が採られており、これにより、ナノ粒子の凝集を防止することが 図られている (特許文献 1)。  [0004] Further, Patent Document 1 employs a method in which the surface of the nanoparticles is directly coated with a porous substance made of an inorganic oxide, thereby preventing aggregation of the nanoparticles. (Patent Document 1).
特許文献 1：特開 2005 - 276688号公報  Patent Document 1: Japanese Patent Laid-Open No. 2005-276688
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0005] し力しながら、ポリマー ·デンドリマー等で保護されたナノ粒子については、このよう なナノ粒子を分離 ·回収することが困難であり、そのため再利用が困難であった。また 、ナノ粒子の活性サイトをポリマー'デンドリマー等で直接被覆しているため、触媒作 用を発揮する活性サイトが減少し触媒活性が低下するという問題があった。 [0005] However, it was difficult to separate and recover such nanoparticles protected by a polymer / dendrimer or the like, and therefore difficult to reuse. In addition, since the active sites of the nanoparticles are directly coated with a polymer dendrimer or the like, there is a problem that the active sites that exert catalytic action are reduced and the catalytic activity is lowered.
また、ナノ粒子の表面に無機酸ィ匕物カゝらなる多孔性物質を直接塗布した触媒ナノ 粒子 (特許文献 1)においては、触媒ナノ粒子の分離 ·回収が容易となるものの、上記 同様、多孔性セラミックスでナノ粒子の表面を直接被覆しているため、ナノ粒子表面 の活性サイトが減少し、ナノ粒子が本来有すると予想される触媒機能が発現できな 、 という問題があった。 In addition, in the case of catalyst nanoparticles (Patent Document 1) in which a porous material such as an inorganic oxide is directly applied to the surface of the nanoparticles (patent document 1), although separation and recovery of the catalyst nanoparticles are easy, Since the surface of the nanoparticle is directly covered with porous ceramics, the active sites on the surface of the nanoparticle are reduced, and the catalytic function expected to be inherently possessed by the nanoparticle cannot be expressed. There was a problem.
[0006] 本発明は、叙上に鑑みなされたものであり、その目的とするところは、触媒活性が高 く維持され、さらに分離'回収が容易であるナノ粒子触媒及びその製造方法を提供 することにある。  [0006] The present invention has been made in view of the above, and an object of the present invention is to provide a nanoparticle catalyst that maintains a high catalytic activity and that can be easily separated and recovered, and a method for producing the same. There is.
課題を解決するための手段  Means for solving the problem
[0007] 本発明者らは、鋭意研究を行った結果、触媒を含むコア部と、このコア部を覆うよう に形成された多孔質層とを有する触媒において、コア部と多孔質層との間に中空層 を設けることにより、ナノ粒子の活性サイトが殆ど減少せず、触媒機能が低下しないこ と、多孔質層でナノ粒子を覆うことにより、ナノ粒子が凝集することを防止することがで きることを見出し、本発明を完成するに至った。  [0007] As a result of intensive studies, the present inventors have found that a catalyst having a core part containing a catalyst and a porous layer formed so as to cover the core part includes a core part and a porous layer. By providing a hollow layer between them, the active sites of the nanoparticles are hardly reduced, the catalytic function is not lowered, and the nanoparticles are prevented from aggregating by covering the nanoparticles with a porous layer. As a result, the present invention has been completed.
[0008] したがって、本発明は、触媒粒子を含むコア部と、前記コア部を覆うように形成され た多孔質炭素層とを含む触媒であって、前記コア部と前記多孔質炭素層との間には 、中空層が設けられており、前記中空層は、前記コア部と前記多孔質炭素層との間 に形成された SiO含有層を除去することによって形成される触媒にある。  [0008] Therefore, the present invention provides a catalyst comprising a core part containing catalyst particles and a porous carbon layer formed so as to cover the core part, and the core part and the porous carbon layer In the meantime, a hollow layer is provided, and the hollow layer is in the catalyst formed by removing the SiO-containing layer formed between the core part and the porous carbon layer.
2  2
また、本発明は、触媒粒子を含むコア部と、前記コア部を覆うように形成された多孔 質炭素層とを含む触媒を製造する方法であって、前記コア部を覆うように SiO含有  The present invention also relates to a method for producing a catalyst including a core part including catalyst particles and a porous carbon layer formed so as to cover the core part, the SiO containing so as to cover the core part.
2 層を形成する第一工程と、前記 SiO含有層を覆うように前記多孔質炭素層を形成す  (2) forming the porous carbon layer so as to cover the SiO-containing layer and the first step of forming the layer
2  2
る第二工程と、前記 SiO含有層を除去する第三工程と、を包含する触媒製造方法に  And a third step of removing the SiO-containing layer.
2  2
ある。特に、多孔質炭素層を形成するに際し、コア部を覆う SiO含有層上に多孔質 S  is there. In particular, when forming a porous carbon layer, porous S is formed on the SiO-containing layer covering the core.
2  2
iO含有層を形成し、前記多孔質 SiO含有層の少なくとも一部に炭素源を充填し、 forming an iO-containing layer, filling at least part of the porous SiO-containing layer with a carbon source,
2 2 twenty two
前記炭素源を炭化することによって多孔質炭素層を形成することが好ましい。これは 、多孔質炭素層をより微細なものとすることができるからである。  It is preferable to form a porous carbon layer by carbonizing the carbon source. This is because the porous carbon layer can be made finer.
上述のように多孔質炭素層を形成する場合において、 SiO含有層および多孔質 S  When the porous carbon layer is formed as described above, the SiO-containing layer and the porous S
2  2
iO含有層に包有される SiOを例えばフッ化水素酸溶液およびアルカリ溶液のうち SiO contained in the iO-containing layer, for example, among hydrofluoric acid solution and alkaline solution
2 2 twenty two
の少なくとも一方を用いることにより溶出除去することが好ましい。  It is preferable to elute and remove by using at least one of the above.
[0009] 本発明にお 、て、触媒ナノ粒子とは、触媒粒子を含むコア部が 0. 5ηπ！〜 500nm の直径を有する触媒を意味するものとする。  In the present invention, the catalyst nanoparticle means that the core portion including the catalyst particle is 0.5 ηπ! It shall mean a catalyst having a diameter of ˜500 nm.
発明の効果 [0010] コア部と多孔質炭素層との間に中空層が設けられているため、触媒の活性サイトが 減少せず、高い触媒機能が得られる。さらに多孔質炭素層で触媒が覆われるため、 金属ナノ粒子を触媒とする場合には、当該ナノ粒子が凝集することを防止することが でき、触媒活性を高く維持することができる。また、ナノ粒子を含むコア部が多孔質炭 素層により覆われているため、ナノ粒子を分離 ·回収した後、触媒として再利用するこ とが容易となる。 The invention's effect [0010] Since the hollow layer is provided between the core portion and the porous carbon layer, the active site of the catalyst is not reduced, and a high catalytic function is obtained. Furthermore, since the catalyst is covered with a porous carbon layer, when metal nanoparticles are used as a catalyst, the nanoparticles can be prevented from agglomerating and the catalytic activity can be maintained high. In addition, since the core portion including the nanoparticles is covered with the porous carbon layer, the nanoparticles can be easily reused as a catalyst after being separated and collected.
したがって、本発明によれば、触媒活性が高く維持され、さらに分離 ·回収が容易で あるナノ粒子触媒及びその製造方法を提供することができる。  Therefore, according to the present invention, it is possible to provide a nanoparticle catalyst that maintains a high catalytic activity and that can be easily separated and recovered and a method for producing the same.
図面の簡単な説明  Brief Description of Drawings
[0011] [図 1]図 1は、本発明に係る製造方法により作製される、多孔質炭素層に内包された 触媒の断面図である。  [0011] FIG. 1 is a cross-sectional view of a catalyst encapsulated in a porous carbon layer produced by the production method according to the present invention.
[図 2]図 2は、多孔質炭素層の一部を取り除いた触媒の斜視図である。  FIG. 2 is a perspective view of the catalyst with a part of the porous carbon layer removed.
[図 3a]図 3aは、本発明に係る多孔質炭素層に内包された触媒の製造工程を示した 図である。  [FIG. 3a] FIG. 3a is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
[図 3b]図 3bは、本発明に係る多孔質炭素層に内包された触媒の製造工程を示した 図である。  [FIG. 3b] FIG. 3b is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
[図 3c]図 3cは、本発明に係る多孔質炭素層に内包された触媒の製造工程を示した 図である。  [FIG. 3c] FIG. 3c is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
[図 3d]図 3dは、本発明に係る多孔質炭素層に内包された触媒の製造工程を示した 図である。  [Fig. 3d] Fig. 3d is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
[図 3e]図 3eは、本発明に係る多孔質炭素層に内包された触媒の製造工程を示した 図である。  [FIG. 3e] FIG. 3e is a view showing a production process of a catalyst encapsulated in a porous carbon layer according to the present invention.
[図 4]図 4は、中空状多孔質炭素層に内包された Pt触媒 (Pt— mhC)の TEM写真で ある。  [FIG. 4] FIG. 4 is a TEM photograph of a Pt catalyst (Pt—mhC) encapsulated in a hollow porous carbon layer.
[図 5]図 5は、触媒による変換効率を示したグラフである。  FIG. 5 is a graph showing the conversion efficiency by catalyst.
[図 6]図 6は、中空状多孔質炭素層に内包された Pt触媒の電極触媒反応の結果であ る  [Fig. 6] Fig. 6 is a result of an electrocatalytic reaction of a Pt catalyst encapsulated in a hollow porous carbon layer.
[図 7]図 7は、中空状多孔質炭素層に内包された Rh触媒 (Rh— mhC)の TEM写真 である。 [Figure 7] Figure 7 shows a TEM photograph of Rh catalyst (Rh—mhC) encapsulated in a hollow porous carbon layer. It is.
[図 8]図 8は、中空状多孔質炭素層に内包された Pd触媒 (Pd— mhC)の TEM写真 である。  FIG. 8 is a TEM photograph of a Pd catalyst (Pd—mhC) encapsulated in a hollow porous carbon layer.
[図 9]図 9は、中空状多孔質炭素層に内包された Ru触媒 (Ru— mhC)の TEM写真 である。  FIG. 9 is a TEM photograph of a Ru catalyst (Ru-mhC) encapsulated in a hollow porous carbon layer.
[図 10]図 10は、中空状多孔質炭素層に内包された Au触媒 (Au— mhC)の TEM写 真である。  FIG. 10 is a TEM photograph of Au catalyst (Au—mhC) encapsulated in a hollow porous carbon layer.
符号の説明  Explanation of symbols
[0012] 1 コア部 [0012] 1 core part
2 シリカ含有層  2 Silica-containing layer
2'中空層  2 'hollow layer
3 多孔質シリカ含有層  3 Porous silica-containing layer
3'多孔質炭素層  3 'porous carbon layer
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0013] 以下、図面を参照しながら、本発明に係る多孔質炭素層に内包された触媒の製造 方法に関して詳細に説明する。し力しながら、以下に示す実施の形態は例示するも のであって、本発明はこれらの実施の形態に限定されるものではない。また、本明細 書において、全図面を通して同一部材は同一の参照番号により示している。また、本 出願において、触媒粒子とは、コア部に含まれるものであって、実際に汚染物質等の 反応物質に触媒作用を及ぼすものである。  [0013] Hereinafter, a method for producing a catalyst contained in a porous carbon layer according to the present invention will be described in detail with reference to the drawings. However, the embodiments described below are merely examples, and the present invention is not limited to these embodiments. In the present specification, the same members are denoted by the same reference numerals throughout the drawings. Further, in the present application, the catalyst particles are contained in the core portion and actually act on a reaction material such as a pollutant.
[0014] (実施の形態 1)  [0014] (Embodiment 1)
図 1は、本発明に係る製造方法により作製される、多孔質炭素層に内包された触媒 の断面図であり、図 2は、多孔質炭素層 3'の一部を取り除いた触媒の斜視図である 。当該触媒は、図 1及び 2に示すように、触媒粒子を含むコア部 1と、コア部 1を離間 して覆う多孔質炭素層 3'と、を備え、コア部 1と多孔質炭素層 3'との間に中空層 2' が介在する。また、多孔質炭素層 3 'は、炭素からなる、若しくは炭素を含んでなり、炭 素からなる部分は、発達した細孔からなる多孔質組織を有する。  FIG. 1 is a cross-sectional view of a catalyst encapsulated in a porous carbon layer produced by the production method according to the present invention, and FIG. 2 is a perspective view of the catalyst with a part of the porous carbon layer 3 ′ removed. Is. As shown in FIGS. 1 and 2, the catalyst includes a core part 1 containing catalyst particles, and a porous carbon layer 3 ′ that covers the core part 1 with a space therebetween, and the core part 1 and the porous carbon layer 3 A hollow layer 2 'is interposed between them. The porous carbon layer 3 ′ is made of carbon or contains carbon, and the portion made of carbon has a porous structure made of developed pores.
[0015] 多孔質炭素層 3'は多孔質組織により構成されているため、触媒作用を受ける溶液 等反応物質が多孔質組織力ゝら多孔質炭素層 3 'の内側に滲入し、触媒粒子を含むコ ァ部 1に接触して触媒作用を受ける。また、本発明では、触媒粒子を含むコア部 1を 多孔質体で直接被覆するのではなぐコア部 1と多孔質炭素層 3 'との間に中空層 2' を介在させてコァ部 1を多孔質炭素層 3，で被覆するため、コア部 1に含まれる触媒粒 子の活性サイトは露出された状態にあり触媒活性を高く保つことができる。また、通常 ナノオーダーサイズの触媒粒子は凝集して触媒作用を低下させてしまうのであるが、 本件発明では触媒粒子を含むコア部 1が多孔質炭素層 3 'により被覆されているため 、コア部同士が凝集してしまう虞はない。そのため、触媒の活性を高く保つことができ る。 [0015] Since the porous carbon layer 3 'is composed of a porous structure, a solution that is catalyzed The iso-reactive substance penetrates into the porous carbon layer 3 ′ with the porous tissue force and contacts the core part 1 containing the catalyst particles to be catalyzed. In the present invention, the core portion 1 containing the catalyst particles is not directly covered with the porous body, and the core portion 1 is formed by interposing the hollow layer 2 ′ between the core portion 1 and the porous carbon layer 3 ′. Since it is covered with the porous carbon layer 3, the active sites of the catalyst particles contained in the core portion 1 are exposed, and the catalytic activity can be kept high. In general, nano-order sized catalyst particles aggregate to reduce the catalytic action. In the present invention, since the core portion 1 containing the catalyst particles is covered with the porous carbon layer 3 ′, the core portion There is no risk of aggregation between them. Therefore, the activity of the catalyst can be kept high.
[0016] 以下に、本発明に係る多孔質炭素層に内包された触媒の製造方法、及び当該触 媒を構成する各構成要素に関して具体的に説明する。  [0016] Hereinafter, a method for producing a catalyst included in a porous carbon layer according to the present invention and each component constituting the catalyst will be specifically described.
[0017] 〈多孔質炭素層に内包された触媒の製造方法〉  <Method for Producing Catalyst Encapsulated in Porous Carbon Layer>
最初に、図 3a〜3eを参照しながら、本発明の好ましい実施の形態に係る、多孔質 炭素層に内包された触媒の製造方法につ!、て説明する。本発明の好ま 、実施の 形態に係る触媒の作製方法は、 1.触媒粒子を含むコア部を準備する工程 (コア部の 準備工程)と、 2.コア部の表面を直接シリカ含有層で被覆する工程 (シリカ含有層形 成工程)と、 3.シリカ含有層を多孔質シリカ含有層で直接被覆する工程 (多孔質シリ 力含有層形成工程)と、 4.多孔質シリカ含有層に炭素源を充填する工程 (炭素源充 填工程)と、 5.炭素源を炭化して多孔質炭素層を形成する工程 (炭化工程)と、 6.シ リカ含有層および多孔質シリカ含有層に包有されるシリカを溶解'除去する工程 (シリ 力溶解 ·除去工程)と、を含み、必要に応じて、 7.触媒を後処理する工程 (後処理工 程)を含んでいてもよい。  First, a method for producing a catalyst included in a porous carbon layer according to a preferred embodiment of the present invention will be described with reference to FIGS. A method for producing a catalyst according to a preferred embodiment of the present invention includes: 1. a step of preparing a core portion containing catalyst particles (a preparation step of a core portion); (Silica-containing layer forming step); 3. directly covering the silica-containing layer with the porous silica-containing layer (porous silica-containing layer forming step); and 4. carbon source in the porous silica-containing layer. Filling process (carbon source filling process), 5. carbon source carbonization to form a porous carbon layer (carbonization process), and 6. inclusion in silica-containing layer and porous silica-containing layer And a step of dissolving and removing the silica (silicic force dissolution / removal step), and optionally 7. a step of post-treating the catalyst (post-treatment step).
[0018] 1)コア部 1の準備  [0018] 1) Preparation of core part 1
本発明に係る多孔質炭素層に内包された触媒を作製するに際し、まず、コア部 1を 準備する（図 3a)。コア部 1は、ナノスケールの触媒粒子でもよぐまた、数ナノメートル カゝらサブマイクロメートルの触媒粒子でもよ ヽ。また酸化物の触媒粒子を担体として ナノスケールの触媒粒子や金属イオンがナノスケールの球体中に分散されて ヽても よぐまたナノスケールの触媒粒子自体をコア部 1としてもよい。ここで、担体に分散さ れる触媒又はコア部 1をなす触媒ナノ粒子の作製方法としては、特に限定されるもの ではないが、含浸法、液相還元法等により作製することができる。 In preparing the catalyst encapsulated in the porous carbon layer according to the present invention, first, the core portion 1 is prepared (FIG. 3a). The core 1 can be nanoscale catalyst particles or sub-micrometer catalyst particles of several nanometers. In addition, nanoscale catalyst particles and metal ions may be dispersed in nanoscale spheres using oxide catalyst particles as a support, or nanoscale catalyst particles themselves may be used as core portion 1. Where dispersed in the carrier The method for producing the catalyst or the catalyst nanoparticles forming the core part 1 is not particularly limited, but can be produced by an impregnation method, a liquid phase reduction method, or the like.
コア部 1を含浸法により作製する場合、触媒となる金属ナノ粒子あるいは金属イオン のもとで、ある金属塩を溶解させた溶液に担体を浸し、乾燥させること〖こより、あるい は必要であれば乾燥した粒子を下記の液相還元ある 、は Hガスによる還元処理を  When the core part 1 is produced by the impregnation method, it is necessary or necessary to immerse the carrier in a solution in which a metal salt is dissolved under a metal nanoparticle or metal ion serving as a catalyst and dry it. For example, the dried particles can be reduced by the following liquid phase reduction or H gas.
2  2
すること〖こより作製することができる。この場合、大きさが 0. 5ηπ！〜 5nmの範囲にある 触媒ナノ粒子や金属イオン力もなる触媒が分散したコア部 1を得ることができる。 コア部 1を液相還元法により作製する場合、ポリマーなどの保護剤を含む溶液に溶 解させた触媒金属原料や上記含浸法により担体に分散させた触媒金属原料に対し て、アルコール、水素化ホウ素カリウム、水素化ホウ素ナトリウム、ヒドラジンなどの還 元剤を加えることにより、金属ナノ粒子あるいは、金属ナノ粒子が分散された担体から なるコア部 1を得ることができる。  It is possible to make it from Tsujiko. In this case, the size is 0.5ηπ! A core part 1 in which catalyst nanoparticles in the range of ˜5 nm and a catalyst having a metal ion force are dispersed can be obtained. When core part 1 is prepared by a liquid phase reduction method, alcohol or hydrogenation is applied to the catalyst metal raw material dissolved in a solution containing a protective agent such as a polymer or the catalyst metal raw material dispersed in the support by the impregnation method. By adding a reducing agent such as potassium borohydride, sodium borohydride, hydrazine, it is possible to obtain the core 1 composed of metal nanoparticles or a carrier in which metal nanoparticles are dispersed.
[0019] 2)シリカ含有層形成工程  [0019] 2) Silica-containing layer forming step
続いて、上述のようにして得られたシングルナノスケールのコア部 1の表面上に、除 去されることにより中空層となるシリカ含有層（第 1層） 2を形成する。図 3bにシリカ含 有層で直接被覆されたコア部 1を図示する。コア部 1をシリカ含有層で被覆するに際 し、コア部 1と、シリカ含有層の前駆物質、例えばテトラエトキシシラン (TEOS)と、を 溶液中で混合し、 TEOSを加水分解および脱水縮合反応させる。  Subsequently, a silica-containing layer (first layer) 2 that becomes a hollow layer is formed on the surface of the single nanoscale core portion 1 obtained as described above. Figure 3b shows the core 1 directly coated with a silica-containing layer. When coating the core part 1 with a silica-containing layer, the core part 1 and a precursor of the silica-containing layer, for example, tetraethoxysilane (TEOS), are mixed in a solution, and TEOS is hydrolyzed and subjected to a dehydration condensation reaction. Let
[0020] 以下に、シリコンアルコキシド（アルコキシシラン）を用いた場合の加水分解反応及 び脱水縮合反応にっ ヽて説明する。典型的なシリコンアルコキシドの加水分解反応 及び脱水縮合反応は、以下の反応式 A, Bに従って進行する。  [0020] Hereinafter, the hydrolysis reaction and dehydration condensation reaction in the case of using silicon alkoxide (alkoxysilane) will be described. A typical hydrolysis reaction and dehydration condensation reaction of silicon alkoxide proceed according to the following reaction formulas A and B.
A.加水分解反応  A. Hydrolysis reaction
Si (OR) +4H 0→Si(OH) +4ROH  Si (OR) + 4H 0 → Si (OH) + 4ROH
4 2 4  4 2 4
B.脱水縮合反応  B. Dehydration condensation reaction
Si (OH) +Si(OH) →(OH) Si— O— Si(OH) +H O  Si (OH) + Si (OH) → (OH) Si— O— Si (OH) + H O
4 4 3 3 2  4 4 3 3 2
[0021] 特にシリコンアルコキシドとして TEOS (テトラエトキシシラン、 Si (OCH CH ) )を  In particular, TEOS (tetraethoxysilane, Si (OCH 2 CH 3)) is used as a silicon alkoxide.
2 3 4 用いた場合における加水分解反応及び脱水縮合反応の一例を示す (反応式 C, D) C.加水分解反応 2 3 4 Examples of hydrolysis and dehydration condensation reactions when used (Reaction formulas C, D) C. Hydrolysis reaction
Si (OCH CH ) +4H 0→Si(OH) +4CH CH OH  Si (OCH CH) + 4H 0 → Si (OH) + 4CH CH OH
2 3 4 2 4 2 3  2 3 4 2 4 2 3
D.脱水縮合反応  D. Dehydration condensation reaction
Si (OH) +Si(OH) →(OH) Si— O— Si(OH) +H O  Si (OH) + Si (OH) → (OH) Si— O— Si (OH) + H O
4 4 3 3 2  4 4 3 3 2
上述の反応 (反応式 C, D)により、コア部 1の表面上にシリカ含有層が形成される（ 図 3b)。このようにして形成されたシリカ含有層は、細孔を殆ど含まない層であり、後 述のように、 SiOを溶解除去可能な溶液により除去されることにより、中空層 2'となる  A silica-containing layer is formed on the surface of the core part 1 by the above reaction (reaction formulas C and D) (FIG. 3b). The silica-containing layer thus formed is a layer containing almost no pores, and becomes a hollow layer 2 ′ by removing SiO with a solution capable of dissolving and removing, as described later.
2 3)多孔質シリカ含有層形成工程  2 3) Porous silica-containing layer formation process
続いて、図 3cに示すように、シリカ含有層 2上に、多孔質シリカ含有層 3を形成する 。ここで、多孔質シリカ含有層 3を構成する材料はシリカ含有層 2を構成する材料と同 一であることが好ましい。同一の溶液により同時に溶解除去することができるからであ る。上記シリカ含有層で被覆された触媒粒子を、例えば、テトラエトキシシラン (TEO 基を 1つ以上含むシリコンアルコキシドと、を含む溶液中に懸濁させて、これらシリコン アルコキシドを加水分解および脱水縮合反応させることにより、シリカ含有層 2の表面 を、アルキル基を含むシリカ層（多孔質シリカ含有層 3となる層）で被覆する。具体的 には、まず、下記式 Eに従って、 TEOS (Si(OC H ) )を加水分解し、 Si (OH) を生  Subsequently, as shown in FIG. 3 c, the porous silica-containing layer 3 is formed on the silica-containing layer 2. Here, the material constituting the porous silica-containing layer 3 is preferably the same as the material constituting the silica-containing layer 2. This is because they can be dissolved and removed simultaneously with the same solution. The catalyst particles coated with the silica-containing layer are suspended, for example, in a solution containing tetraethoxysilane (silicon alkoxide containing one or more TEO groups), and these silicon alkoxides are hydrolyzed and subjected to dehydration condensation reaction. As a result, the surface of the silica-containing layer 2 is covered with a silica layer containing an alkyl group (a layer that becomes the porous silica-containing layer 3), specifically, TEOS (Si (OC H )) To produce Si (OH)
2 5 4 4 成する。また、当該反応と前後して、下記式 Fに従って、 ODTSを加水分解しォクタ デシル基を有する Si (OH) (C H )を生成する。これらは、式 Gに従って、水酸基  2 5 4 4 Further, before and after the reaction, according to the following formula F, ODTS is hydrolyzed to produce Si (OH) (C H) having an octadecyl group. These are hydroxyl groups according to formula G
3 18 37  3 18 37
同士が脱水縮合反応することにより結合する。これにより、架橋構造が成長し多孔質 シリカ含有層 3となる層が形成される。 They are bonded by a dehydration condensation reaction. As a result, a crosslinked structure grows and a layer that becomes the porous silica-containing layer 3 is formed.
以下に TEOS (Si (OC H ) )及び ODTS (オタタデシルトリメトキシシラン、 Si (OC  TEOS (Si (OC H)) and ODTS (Otadecyltrimethoxysilane, Si (OC
2 5 4  2 5 4
H ) (C H ) )の加水分解反応及び脱水縮合反応の一例を示す。  An example of the hydrolysis reaction and dehydration condensation reaction of H) (C H)) is shown.
3 3 18 37  3 3 18 37
E.加水分解反応 (TEOS)  E. Hydrolysis (TEOS)
Si (OCH CH ) +4H 0→Si(OH) +4CH CH OH  Si (OCH CH) + 4H 0 → Si (OH) + 4CH CH OH
2 3 4 2 4 2 3  2 3 4 2 4 2 3
F.加水分解反応 (ODTS)  F. Hydrolysis (ODTS)
Si (OCH ) (C H ) + 3H 0→Si (OH) (C H ) + 3CH OH G.脱水縮合反応 Si (OCH) (CH) + 3H 0 → Si (OH) (CH) + 3CH OH G. Dehydration condensation reaction
Si (OH) (C H ) +Si(OH)→(C H ) (OH) Si—0— Si(OH) +H O  Si (OH) (C H) + Si (OH) → (C H) (OH) Si—0— Si (OH) + H O
3 18 37 4 18 37 2 3 2 3 18 37 4 18 37 2 3 2
(C H ) (OH) Si-O-Si(OH) +Si (OH) (C H )→(C H ) (OH) Si—(C H) (OH) Si-O-Si (OH) + Si (OH) (C H) → (C H) (OH) Si—
18 37 2 3 3 18 37 18 37 218 37 2 3 3 18 37 18 37 2
O-Si (OH) -O-Si(OH) (C H ) O-Si (OH) -O-Si (OH) (C H)
2 2 18 37  2 2 18 37
上述の反応 (反応式 E, F及び G)により、シリカ含有層の表面上に多孔質シリカ含 有層となる層が形成される（図 3c)。  A layer that becomes a porous silica-containing layer is formed on the surface of the silica-containing layer by the above reaction (reaction formulas E, F, and G) (FIG. 3c).
さらにこれを熱処理して当該多孔質シリカ含有層となる層に含まれるォクタデシル 基を分解 '除去することで、分解除去されたォクタデシル基部分が細孔となり、多孔 質シリカ含有層 3が形成される。  Further, this is heat-treated to decompose and remove the octadecyl group contained in the layer that becomes the porous silica-containing layer, so that the decomposed and removed octadecyl group portion becomes pores, and the porous silica-containing layer 3 is formed. .
多孔質シリカ含有層 3を形成するシリコンアルコキシドに含まれるアルキル基は、分 子内に 2つ以上あっても良ぐ直鎖状であってもまたは分岐状であっても良ぐアルキ ル基の末端や中間に官能基等を含むものでも良い。直鎖または分岐状のアルキル 基の代表例として、メチル基、ェチル基、 n—プロピル基、イソプロピル基、 n—ブチル 基、 sec—ブチル基、 tert—ブチル基、ペンチル基、イソアミル基、へキシル基、オタ チル基、ォクタデシルチル基等が挙げられ、含まれる官能基の代表例として、フエ二 ル基、アミノ基、ヒドロキシル基、フルォロ基、チオール基等が挙げられる。また、多孔 質シリカ含有層 3の形成においては、テトラエトキシシラン (TEOS)等のアルコキシシ ランを加えな 、で、これらのアルキル基を 1つ以上含むシリコンアルコキシド (例えば、 ODTS)のみを加水分解 '脱水縮合させたあと、熱処理を行ってもよいが、多孔質層 を完全に形成しうる点で、 ODTSに TEOSをカ卩えて加水分解 '脱水縮合反応を行うこ とが好ましい。  The alkyl group contained in the silicon alkoxide that forms the porous silica-containing layer 3 is an alkyl group that may be two or more in the molecule, which may be linear or branched. It may contain a functional group or the like at the end or in the middle. Typical examples of linear or branched alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, isoamyl, and hexyl. Group, octyl group, octadecylyl group and the like, and representative examples of the functional group included include a phenyl group, an amino group, a hydroxyl group, a fluoro group, and a thiol group. In addition, in the formation of the porous silica-containing layer 3, only silicon alkoxide (for example, ODTS) containing one or more of these alkyl groups is hydrolyzed without adding alkoxysilane such as tetraethoxysilane (TEOS). 'After dehydrating and condensing, heat treatment may be performed. However, it is preferable to carry out hydrolysis and dehydrating and condensing reaction by adding TEOS to ODTS in order to form a porous layer completely.
アルコキシシランの具体例としては、テトラメトキシシラン (TMOS)、テトラエトキシシ ラン (TEOS)、テトラブトキシシラン (TBOS)等が挙げられる。  Specific examples of the alkoxysilane include tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), and tetrabutoxysilane (TBOS).
4)炭素源充填工程  4) Carbon source filling process
続いて、炭素源であるフエノール榭脂、ポリアクリルアミド、ポリピロール等の榭脂ぁ るいはポリマーをエタノール又はメタノール等の溶媒に溶解させる。そして、図 3dに 示すように、上記多孔質シリカ層 3に形成された無数の細孔内に、上記榭脂を含有 する溶媒を含浸させる。 当該細孔内への充填は、上記榭脂又はポリマーのほ力、グルコース、スクロース、 フルフリルアルコール、ピロールなどを当該無数の細孔内に充填しこれを当該細孔 内でポリマー化してもよぐフエノールとホルムアルデヒドを当該細孔内で重縮合させ てフエノール榭脂を充填させてもよい。さらに、これらの代わりに、より安価な石油ピッ チを当該細孔内に充填させてもよい。 Subsequently, a carbon source such as phenol resin, polyacrylamide, polypyrrole or the like is dissolved in a solvent such as ethanol or methanol. Then, as shown in FIG. 3d, innumerable pores formed in the porous silica layer 3 are impregnated with a solvent containing the coconut resin. The pores may be filled by filling the innumerable pores with the above-mentioned resin or polymer force, glucose, sucrose, furfuryl alcohol, pyrrole, etc., and polymerizing them in the pores. Guphenol and formaldehyde may be polycondensed in the pores and filled with phenol resin. Further, instead of these, cheaper petroleum pitches may be filled in the pores.
5)炭化工程  5) Carbonization process
その後、これらの炭素源を含有する前駆体を 300°C〜900°C、より好ましくは 600 °C〜800°Cで焼成して炭化させる。  Thereafter, the precursor containing these carbon sources is calcined by calcining at 300 ° C. to 900 ° C., more preferably at 600 ° C. to 800 ° C.
[0024] 6)シリカ溶解 ·除去工程 [0024] 6) Silica dissolution and removal process
続いて、図 3eに示すように、シリカ含有層 2を介して多孔質シリカ含有層 3となる層 が被覆された触媒を、 SiOを溶解することができる溶液に浸漬することにより、多孔  Subsequently, as shown in FIG. 3e, the catalyst coated with the layer that becomes the porous silica-containing layer 3 via the silica-containing layer 2 is immersed in a solution capable of dissolving SiO, thereby obtaining a porous material.
2  2
質シリカ含有層 3となる層内の SiOが溶解除去され、多孔質炭素層 3 'が形成され、  SiO in the layer that becomes the porous silica-containing layer 3 is dissolved and removed, and a porous carbon layer 3 ′ is formed,
2  2
さらにシリカ含有層 2が溶解除去され、多孔質炭素層 3'とコア部 1との間に中空層 2' が形成される。多孔質炭素層 3'は、 SiOからなる多孔質シリカ含有層 3を铸型として  Further, the silica-containing layer 2 is dissolved and removed, and a hollow layer 2 ′ is formed between the porous carbon layer 3 ′ and the core part 1. The porous carbon layer 3 ′ is a porous silica-containing layer 3 made of SiO.
2  2
形成される。  It is formed.
ここで、 SiOを溶解除去することができる溶液として、フッ化水素酸溶液や、 NaOH  Here, as a solution capable of dissolving and removing SiO, hydrofluoric acid solution or NaOH
2  2
溶液、 KOH溶液などのアルカリ溶液が挙げられる。  Examples include alkaline solutions such as solutions and KOH solutions.
[0025] 7)活性化処理 [0025] 7) Activation treatment
その後、必要に応じて水素雰囲気下での熱処理を行うことで還元処理を行い、本 発明に係る多孔質炭素層に内包された触媒を得ることができる。  Thereafter, a reduction treatment is performed by performing a heat treatment in a hydrogen atmosphere as necessary, and a catalyst encapsulated in the porous carbon layer according to the present invention can be obtained.
[0026] 続いて、本発明に係る触媒の各構成要素について詳細に説明する。 Subsequently, each component of the catalyst according to the present invention will be described in detail.
〈コア部 1〉  <Core part 1>
コア部 1は、触媒粒子力もなるか、若しくは触媒粒子を含んでなり、中空層 2を介し て多孔質炭素層 3により離間して覆われている。コア部 1は、実際に反応物質に対し て触媒作用を及ぼす。本発明に係るコア部 1にお ヽて、鉄 (Fe)、ルテニウム (Ru)、 コノルト（Co)、ロジウム（Rh)、イリジウム（Ir)、ニッケル (Ni)、パラジウム（Pd)、白金 (Pt)、金 (Au)、銅 (Cu)、および銀 (Ag)からなる群力 選択される少なくとも 1種を 触媒粒子として含むことが好ましい。しかし、これらの触媒粒子に限定されるものでは なぐ触媒作用を示す限り如何なる物質を含んでいても良い。また、触媒粒子は、単 体、合金、イオン、あるいは無機塩等の各種形態であってよい。 The core portion 1 also has catalyst particle force or includes catalyst particles, and is covered with a porous carbon layer 3 with a hollow layer 2 therebetween. The core part 1 actually acts on the reactants. In the core part 1 according to the present invention, iron (Fe), ruthenium (Ru), conol (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt ), Gold (Au), copper (Cu), and silver (Ag) are preferably included as catalyst particles. However, it is not limited to these catalyst particles Any substance may be included as long as it exhibits a catalytic action. Further, the catalyst particles may be in various forms such as a single body, an alloy, an ion, or an inorganic salt.
[0027] コア部 1は、触媒機能を良好に発揮しうる限り、如何なる形状であっても良い。コア 部 1自体が触媒粒子を形成し、これが略球形である場合、その直径は 0. 5ηπ！〜 5n mの範囲にあることが好ましぐ 0. 5nm〜2nmの範囲にあることがさらに好ましい。こ のようなサイズの触媒粒子は、触媒粒子を構成する原子のうち、触媒作用に供される 露出された原子が全原子数に対して 50%以上となるため、高い触媒活性を示す。  [0027] The core portion 1 may have any shape as long as the catalyst function can be satisfactorily exhibited. When the core part 1 itself forms catalyst particles, which are substantially spherical, the diameter is 0.5ηπ! It is preferably in the range of ˜5 nm, and more preferably in the range of 0.5 nm to 2 nm. The catalyst particles having such a size exhibit high catalytic activity because the number of exposed atoms used for catalysis among the atoms constituting the catalyst particles is 50% or more of the total number of atoms.
[0028] また、コア部 1は、触媒粒子を一部に含んでいればよい。この場合、コア部 1の直径 は 0. 5nm〜500nmの範囲にあることが好ましぐ 0. 5nm〜100nmの範囲にあるこ とが更に好ましい。また、コア部 1は、例えば、その表層部分に触媒粒子を含んでい ても良い。このようにコア部表層のみが触媒粒子力 構成されていると、触媒の原子 利用効率が向上し活性サイトを有効に利用することができるからである。  [0028] The core portion 1 only needs to contain catalyst particles in part. In this case, the diameter of the core part 1 is preferably in the range of 0.5 nm to 500 nm, and more preferably in the range of 0.5 nm to 100 nm. Further, the core portion 1 may include catalyst particles in the surface layer portion, for example. This is because if only the surface layer of the core part has a catalyst particle force, the atom utilization efficiency of the catalyst is improved and the active site can be used effectively.
[0029] ここで、通常、コア部 1は、一体として構成され、その一つが多孔質炭素層 3'内に 閉じ込められているが、コア部 1は、多孔質炭素層 3'内に複数存在しても良い。当該 触媒粒子を複数個存在させて、金属の含有割合を増やせば、燃料電池触媒 (例え ば固体高分子型の燃料電池のアノード (酸素還元側)）に利用することができる。当 該固体高分子型燃料電池にぉ 、て、超多孔性のシェル構造は酸素の金属 (Pt)へ のアクセスや生成する水の排出を容易にすることができる。  [0029] Here, normally, the core part 1 is integrally formed, one of which is confined in the porous carbon layer 3 ', but there are a plurality of core parts 1 in the porous carbon layer 3'. You may do it. If a plurality of the catalyst particles are present and the metal content is increased, the catalyst can be used as a fuel cell catalyst (for example, an anode (oxygen reduction side) of a polymer electrolyte fuel cell). In the polymer electrolyte fuel cell, the superporous shell structure can facilitate access to oxygen metal (Pt) and discharge of generated water.
[0030] また、コア部 1は中空状であっても良い。さらに、コア部 1は、少なくとも一部に多孔 質組織を有し、その多孔質組織自身が触媒となってもよい。このような触媒として、ゼ オライト（Si— O— Ai— O— Si)、ニオブ酸、ポリ酸等が挙げられる。ここで、ゼォライト とは、結晶中に微細孔を持つアルミノ珪酸塩であり、また、ニオブ酸とは、金属ニオブ (重金属）の酸ィ匕物である。さらに、ポリ酸とは、バナジウム (V5+)、ニオブ (Nb5+)、モリ ブデン (Mo6+)、タングステン (W6+)、タンタル (Ta5+)等の遷移金属イオンが酸素ィォ ン (o2_)により配位されてなるある種のォキソ酸が別種の複数のォキソ酸により重合 された化合物をいう。中心のォキソ酸を形成する元素をへテロ元素、その周りに重合 するォキソ酸の元素をポリ元素と呼び、ヘテロ元素としては、 Si、 P、 As、 S、 Fe、 Co 等、ポリ元素としては Mo、 W、 V、 Nb、 Ta等が用いられる。 コア部 1がゼオライト等の多孔質組織自体を有する場合、コア部 1の大きさは、ナノ スケールに限定されず、数/ z m〜数十 mmの大きさを有していても良い。 [0030] The core portion 1 may be hollow. Furthermore, the core part 1 may have a porous structure at least in part, and the porous structure itself may serve as a catalyst. Examples of such a catalyst include zeolite (Si—O—Ai—O—Si), niobic acid, polyacid, and the like. Here, zeolite is an aluminosilicate having fine pores in the crystal, and niobic acid is an oxide of metallic niobium (heavy metal). In addition, polyacids refer to transition metal ions such as vanadium (V 5+ ), niobium (Nb 5+ ), molybdenum (Mo 6+ ), tungsten (W 6+ ), tantalum (Ta 5+ ) o emissions (o 2_) certain Okiso acid formed by coordinated by refers to a polymerized compound of a plurality of Okiso acid different kind. The element that forms the central oxo acid is called a hetero element, and the oxo acid element that polymerizes around it is called a poly element, and the hetero elements include Si, P, As, S, Fe, Co, etc. Mo, W, V, Nb, Ta, etc. are used. When the core part 1 has a porous structure itself such as zeolite, the size of the core part 1 is not limited to the nanoscale, and may have a size of several tens / zm to several tens of mm.
また、このような多孔質組織の微細孔に他の微小な触媒粒子が分散されて 、ても 良い。  Further, other fine catalyst particles may be dispersed in the fine pores of such a porous structure.
[0031] 〈多孔質炭素層 3'〉  <Porous carbon layer 3 '>
本発明において、触媒を覆う多孔質層は、炭素からなることを特徴としている。多孔 質層が炭素力 構成されることにより、一般に疎水性である反応物に対して親和性が 高ぐその結果、反応物が効果的に捕捉され (濃縮効果)、触媒粒子表面に効果的 に供給される。また、炭素からなる層は、熱処理をするだけで除去できるため、触媒 金属の回収とリサイクルが容易である。  In the present invention, the porous layer covering the catalyst is made of carbon. Due to the carbon structure of the porous layer, it has a high affinity for reactants that are generally hydrophobic, so that the reactants are effectively trapped (concentration effect) and effectively on the catalyst particle surface. Supplied. In addition, since the carbon layer can be removed simply by heat treatment, the catalyst metal can be easily recovered and recycled.
また、多孔質炭素層 3'は、触媒粒子を含むコア部 1を中空層 2'を介して覆ってい る力 このように、中空層 2'で触媒粒子を含むコア部 1を覆うことにより、コア部 1の凝 集を防止することができる。また、ナノスケールの触媒粒子を分離 '回収しやすくなる 。また、コア部 1と多孔質炭素層 3'との間に中空層 2'が介在するため、活性サイトが 減殺されることがなく良好な触媒作用を発揮することができる。  Further, the porous carbon layer 3 ′ has a force that covers the core part 1 containing the catalyst particles via the hollow layer 2 ′. Thus, by covering the core part 1 containing the catalyst particles with the hollow layer 2 ′, Aggregation of the core part 1 can be prevented. It also makes it easier to separate and recover the nanoscale catalyst particles. In addition, since the hollow layer 2 ′ is interposed between the core portion 1 and the porous carbon layer 3 ′, the active site is not killed and good catalytic action can be exhibited.
[0032] 多孔質炭素層 3'は、中空状であって、多孔質炭素層 3'の少なくとも一部に多孔質 構造を含む。この多孔質構造は、少なくとも一部に、多孔質炭素層 3 '外力 中空層 2 ，まで連通する微細孔を含んで 、る。  [0032] The porous carbon layer 3 'is hollow and includes a porous structure in at least a part of the porous carbon layer 3'. This porous structure includes, at least in part, micropores communicating with the porous carbon layer 3 ′ and the external force hollow layer 2.
[0033] ここで、多孔質炭素層 3'の形状は、球状に限定されず、上記と同様の効果を奏す る限り如何なる形状であっても良い。  [0033] Here, the shape of the porous carbon layer 3 'is not limited to a spherical shape, and may be any shape as long as the same effect as described above is obtained.
[0034] また、多孔質炭素層 3'の直径は、 ΙΟηπ！〜 1 μ mであることが好ましい。触媒の回 収のし易さ等のためである。  [0034] The diameter of the porous carbon layer 3 'is' ηπ! ˜1 μm is preferred. This is because of the ease of catalyst recovery.
[0035] さらに、多孔質炭素層 3'の微細孔の径は、多孔質炭素層 3'外から汚染物質、臭い 、汚水、微生物等を通過させ、かつ、コア部 1が流出しないような大きさであれば如何 なる大きさであってもよい。多孔質炭素層 3'の微細孔の孔径は、多孔質炭素層 3'に より内包されたコア部 1の直径より小さければ如何なる大きさであっても良いが、 0. 3 nm〜10nmであることが好ましぐ 0. 5nm〜lnmであることがさらに好ましい。孔径 が 0. 5nm以上であれば、芳香族有機化合物でも孔を通過して触媒活性点に到達で きるためであり、孔径が lnm以下であれば、コア部の流出が完全に起こらないためで ある。 [0035] Furthermore, the diameter of the micropores of the porous carbon layer 3 'is large enough to allow contaminants, odors, sewage, microorganisms, etc. to pass through from outside the porous carbon layer 3' and the core portion 1 does not flow out. Any size is acceptable. The pore diameter of the fine pores of the porous carbon layer 3 ′ may be any size as long as it is smaller than the diameter of the core part 1 encapsulated by the porous carbon layer 3 ′, but is 0.3 nm to 10 nm. It is more preferable that the thickness is 0.5 nm to lnm. If the pore size is 0.5 nm or more, even an aromatic organic compound can pass through the pores and reach the catalyst active point. This is because if the pore diameter is 1 nm or less, the core part does not flow out completely.
[0036] 多孔質炭素層 3'の厚さは、上記同様、多孔質炭素層 3'外から汚染物質、臭い、汚 水、微生物等を通過させ、しかも多孔質炭素層 3'自体が耐久性を有する限り如何な る大きさであっても良い。上記条件を考慮すると、多孔質炭素層 3'の厚さは、 lOnm 〜1 μ mの範囲にあることが好ましい。  [0036] The thickness of the porous carbon layer 3 'is the same as described above, and allows contaminants, odors, sewage, microorganisms, etc. to pass from the outside of the porous carbon layer 3', and the porous carbon layer 3 'itself is durable. As long as it has, any size may be used. Considering the above conditions, the thickness of the porous carbon layer 3 ′ is preferably in the range of lOnm to 1 μm.
[0037] 〈分離'回収方法〉  [0037] <Separation 'recovery method>
本発明に係る多孔質炭素層に内包された触媒は、触媒反応終了後に、ろ紙等でろ 過することにより、容易に反応溶液と分離できる。また、遠心分離によって沈降させて 反応溶液と分離してもよい。その後、乾燥させて回収させた触媒はそのまま再使用す るか、必要に応じて活性化処理を施すことで、再使用できる。また、触媒の廃棄に際 して、コア部の触媒が、高価又は希少な元素を使用している場合でも、多孔質炭素 層の炭素分は熱処理によって分解、除去できるため、コア部の元素が容易に回収で きる。  The catalyst encapsulated in the porous carbon layer according to the present invention can be easily separated from the reaction solution by filtering with a filter paper or the like after completion of the catalytic reaction. Alternatively, the reaction solution may be separated by sedimentation by centrifugation. Thereafter, the dried and recovered catalyst can be reused as it is, or can be reused by performing an activation treatment as necessary. In addition, when the catalyst is discarded, even if the core catalyst uses expensive or rare elements, the carbon content of the porous carbon layer can be decomposed and removed by heat treatment. It can be easily recovered.
(実施の形態 2)  (Embodiment 2)
〈触媒の作製方法〉  <Catalyst preparation method>
続いて、本発明の別の好ましい実施の形態に係る触媒の作製方法について説明 する。当該触媒の作製方法は、 1.触媒粒子を含むコア部を準備する工程 (コア部の 準備工程)と、 2.コア部の表面を直接シリカ含有層で被覆する工程 (シリカ含有層形 成工程)と、 3.細孔形成剤を用いてシリカ含有層上に多孔質シリカ含有層を形成す る工程 (多孔質シリカ含有層形成工程)と、 4.多孔質シリカ含有層に炭素源を充填 する工程 (炭素源充填工程)と、 5.炭素源を炭化して多孔質炭素層を形成する工程 (炭化工程)と、 6.シリカ含有層および多孔質シリカ含有層に包有されるシリカを溶解 •除去する工程 (シリカ溶解 ·除去工程)と、を含み、必要に応じて、 7.触媒を後処理 する工程 (後処理工程)を含んで!/ヽてもよ ヽ。実施の形態 1における工程と同様のも のについては説明を省略する。  Subsequently, a method for producing a catalyst according to another preferred embodiment of the present invention will be described. The catalyst production method is as follows: 1. A step of preparing a core part containing catalyst particles (preparation step of core part); 2. A step of directly covering the surface of the core part with a silica-containing layer (silica-containing layer forming step) 3) A step of forming a porous silica-containing layer on the silica-containing layer using a pore-forming agent (a porous silica-containing layer forming step); and 4. A carbon source is filled in the porous silica-containing layer. A step of carbonization (carbon source filling step), 5. a step of carbonizing the carbon source to form a porous carbon layer (carbonization step), and 6. a silica-containing layer and a silica contained in the porous silica-containing layer. It includes a step of dissolution and removal (silica dissolution / removal step) and, if necessary, 7. a step of post-treating the catalyst (post-treatment step)! Explanation of the same steps as those in Embodiment 1 is omitted.
[0038] 3)多孔質シリカ含有層形成工程 [0038] 3) Step of forming porous silica-containing layer
シリカ含有層形成工程で作製されたシリカ含有層被覆触媒と細孔形成剤とを溶媒 に混合し懸濁させて、懸濁溶液を調製する。これにより、当該溶媒中に細孔形成剤 が分散される。ここで、細孔形成剤は、細孔を形成するための铸型となるものであり、 このような細孔形成剤として、例えば、界面活性剤、水溶性ポリマー等が挙げられる。 例えば、細孔形成剤として、界面活性剤を用いた場合、これは上記懸濁溶液ではミ セルとして分散する。界面活性剤としては、特にカチオン性の界面活性剤が好適に 用いられる。ここで、上記界面活性剤としては、 The silica-containing layer-coated catalyst prepared in the silica-containing layer forming step and the pore-forming agent are used as a solvent. To prepare a suspension solution. Thereby, the pore forming agent is dispersed in the solvent. Here, the pore-forming agent has a saddle shape for forming pores. Examples of such a pore-forming agent include surfactants and water-soluble polymers. For example, when a surfactant is used as the pore forming agent, it is dispersed as micelles in the above suspension solution. As the surfactant, a cationic surfactant is particularly preferably used. Here, as the surfactant,
[数 1]  [Number 1]
Figure imgf000015_0001
Figure imgf000015_0001
(n= 7〜21、 R〜Rは、メチル基又は直鎖のアルキル基）で表される第四級アンモ (n = 7 to 21, R to R are methyl groups or linear alkyl groups)
1 4  14
-ゥム塩が挙げられる。具体的には、セチルトリメチルアンモ-ゥムブロミド、ォクチル トリメチルアンモ-ゥムブロミド、デシルトリメチルアンモ-ゥムブロミド、ドデシルトリメチ ルアンモ-ゥムブロミド、テトラデシルトリメチルアンモ-ゥムブロミド、ォクタデシルトリ メチルアンモ-ゥムブロミド、セチルトリメチルアンモ -ゥムクロリド、ォクチルトリメチル アンモ-ゥムクロリド、デシルトリメチルアンモ -ゥムクロリド、ドデシルトリメチルアンモ -ゥムクロリド、テトラデシルトリメチルアンモ -ゥムクロリド、ォクタデシルトリメチルアン モ -ゥムクロリドが挙げられる。好ましくは、セチルトリメチルアンモ-ゥムブロミド (CT AB)である。  -Umu salt. Specifically, cetyltrimethylammonium bromide, octyltrimethylammonium bromide, decyltrimethylammonium bromide, dodecyltrimethylaluminumbromide, tetradecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, cetyltrimethylammonium chloride, octyl Examples thereof include trimethylammonium chloride, decyltrimethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, and octadecyltrimethylammonium chloride. Cetyltrimethyl ammonium bromide (CT AB) is preferred.
[0039] また、シリカ含有層被覆触媒粒子と細孔形成剤とが混合される溶媒としては、水が 用いられる。  [0039] Water is used as a solvent in which the silica-containing layer-coated catalyst particles and the pore-forming agent are mixed.
[0040] 4)炭素源充填工程  [0040] 4) Carbon source filling process
続いて、シリカ含有層 2'により被覆された触媒粒子を含む上記懸濁溶液に、多孔 質シリカ層の前駆物質、例えばテトラエトキシシラン (TEOS)を混合する。これにより 、図 3dに示すように、多孔質シリカ層 3となる層力 シリカ含有層 2の上に形成される。 ここで、多孔質シリカ含有層 3の前駆物質として、例えば TEOSを用いる場合、多孔 質シリカ含有層 3は、 TEOSを加水分解 '脱水縮合させることにより形成される。具体 的には、上記式 Cに従って、 TEOS (Si (OC H ) )を加水分解し、 Si (OH) を生成 Subsequently, a precursor of the porous silica layer, for example, tetraethoxysilane (TEOS) is mixed into the suspension solution containing the catalyst particles coated with the silica-containing layer 2 ′. As a result, as shown in FIG. 3d, a laminar force silica-containing layer 2 that becomes the porous silica layer 3 is formed. Here, when TEOS is used as a precursor of the porous silica-containing layer 3, for example, the porous silica-containing layer 3 is formed by hydrolysis and dehydration condensation of TEOS. Concrete Specifically, according to the above formula C, TEOS (Si (OC H)) is hydrolyzed to produce Si (OH)
2 5 4 4 する（式 C)。この Si (OH) は、上記シリカ含有層 2に引きつけられてシリカ含有層 2を  2 5 4 4 (Formula C). This Si (OH) is attracted to the silica-containing layer 2 to form the silica-containing layer 2.
4  Four
被覆する一方、この Si(OH) は式 Dに従ってその水酸基同士が脱水縮合反応する  On the other hand, this Si (OH) undergoes dehydration condensation reaction between its hydroxyl groups according to Formula D
4  Four
ことにより結合する。これにより、架橋構造が成長し多孔質シリカ含有層が形成される  To join. Thereby, a crosslinked structure grows and a porous silica-containing layer is formed.
[0041] このように、脱水縮合反応により結合してシリカの架橋構造が形成されるに際し、多 孔質シリカ含有層となる層は、界面活性剤力もなるミセルを取り込みながら成長する。 そのため、多孔質シリカ含有層となる層内には、ミセルが分散することとなり、このミセ ルを消失させれば、これが細孔となる。したがって、界面活性剤の疎水基の鎖長を調 整することにより、最終製品に係る触媒の多孔質シリカ含有層 3の細孔径を調整する ことができる。また、細孔形成剤の濃度を調整することにより多孔質層 4の気孔率を調 整することちでさる。 [0041] As described above, when a silica cross-linked structure is formed by the dehydration condensation reaction, the layer that becomes the porous silica-containing layer grows while taking in micelles that also have surfactant power. For this reason, micelles are dispersed in the layer that becomes the porous silica-containing layer, and if these micelles disappear, they become pores. Therefore, the pore diameter of the porous silica-containing layer 3 of the catalyst according to the final product can be adjusted by adjusting the chain length of the hydrophobic group of the surfactant. Further, it is possible to adjust the porosity of the porous layer 4 by adjusting the concentration of the pore forming agent.
[0042] また、本発明に係る触媒の作製方法にお!ヽて、細孔形成剤の混合工程及び多孔 質層の形成工程は、塩基性下で行われることが好ましい。これは、塩基性において 上記脱水縮合反応が適度な速さで進み、その結果良好な多孔質層が得られるから である。  [0042] In addition, in the method for producing a catalyst according to the present invention, the step of mixing the pore-forming agent and the step of forming the porous layer are preferably performed under basic conditions. This is because in the basicity, the dehydration condensation reaction proceeds at an appropriate speed, and as a result, a good porous layer can be obtained.
実施例  Example
[0043] 以下に、本発明に係る触媒の実施例を比較例とともに説明するが、本発明で対象 として 、る触媒は、以下の実施例に限定されな 、ことは言うまでもな 、。  [0043] Hereinafter, examples of the catalyst according to the present invention will be described together with comparative examples. However, it goes without saying that the target catalyst in the present invention is not limited to the following examples.
(実施例 1)  (Example 1)
本発明に係る多孔質炭素層に内包された触媒の製造方法により Ptナノ粒子を内包 した触媒を作製した。  A catalyst encapsulating Pt nanoparticles was produced by the method for producing a catalyst encapsulated in a porous carbon layer according to the present invention.
まず、 6mMの塩化白金酸（H PtCl )水溶液 5πΛ (30 /ζ πιο1)にエタノール（EtO  First, a 6 mM aqueous solution of chloroplatinic acid (H PtCl) in 5πΛ (30 / ζ πιο1) and ethanol (EtO
2 6  2 6
H) 45mLをカロえ、さら〖こ PVP 66mgを添カロし 3時間還流した。その結果、平均粒径 2. 5nmを有する Pt— PVPが得られた。ここで、 Pt— PVPとは、 Pt粒子力PVPにより 被覆されたものを表す。  H) Calored 45 mL, added Sarakako PVP 66 mg and refluxed for 3 hours. As a result, Pt—PVP having an average particle diameter of 2.5 nm was obtained. Here, Pt-PVP represents a material coated with Pt particle force PVP.
その後、 Pt— PVP溶液 4mL (2. 4 μ mol)、トルエン 9mLを混合した溶液を 3000r pmで 10分遠心分離して、ナノ粒子を沈降させ、上澄み液を除去した。この沈殿物に 、エタノール 30mLゝ及び NH (28%) 2mL (94mmol)、 TEOS 0. 2mL (0. 88m Thereafter, a solution obtained by mixing 4 mL (2.4 μmol) of a Pt—PVP solution and 9 mL of toluene was centrifuged at 3000 rpm for 10 minutes to precipitate the nanoparticles, and the supernatant was removed. To this deposit , Ethanol 30mL エ タ ノ ー ル and NH (28%) 2mL (94mmol), TEOS 0.2mL (0.88m
3  Three
mol)を加えて、室温で 6時間撹拌することにより、 TEOSを加水分解 '脱水縮合反応 させた。この溶液にトルエン 50mLを加え、 3000rpmで 10分遠心分離し、シリカ層（ SiO )で被覆された Pt触媒 (以下、 SiOで被覆された Pt触媒を Pt— SiOと表す。 ) mol) was added and stirred at room temperature for 6 hours to hydrolyze and dehydrate the TEOS. To this solution was added 50 mL of toluene, centrifuged at 3000 rpm for 10 minutes, and a Pt catalyst coated with a silica layer (SiO 2) (hereinafter, Pt catalyst coated with SiO is referred to as Pt—SiO 2).
2 2 2 が得られた。 2 2 2 was obtained.
[0044] この Pt— SiOにエタノール 30mL、水 2. OmL、 NH (28%) 2. 55mL (120m  [0044] This Pt—SiO with ethanol 30mL, water 2. OmL, NH (28%) 2. 55mL (120m
2 3  twenty three
mol)、 TEOS 0. 4mL (l. 76mmol)及び ODTS 0. 16mLの混合溶液を加えて、 室温で 2時間撹拌することにより、シリカ層の表面をアルキル基 (ォクタデシル基)を 含むシリカ層で被覆した。この溶液にトルエン 70mLを加えて、 3000rpmで 10分遠 心分離し、残渣を 80°Cで乾燥させた。その後、さらに、これを窒素雰囲気下 550°Cで 4時間焼成した。これにより、シリカ層に含まれるアルキル基が除去され、シリカ層の 表面上に多孔質シリカ層が形成された。その結果、シリカ層を介して多孔質シリカ層 で被覆された Ptナノ粒子が得られた。  mol), TEOS 0.4 mL (l. 76 mmol) and ODTS 0.16 mL mixed solution, and stirred at room temperature for 2 hours to coat the surface of the silica layer with a silica layer containing an alkyl group (octadecyl group) did. To this solution, 70 mL of toluene was added, and centrifuged at 3000 rpm for 10 minutes, and the residue was dried at 80 ° C. Thereafter, this was further baked at 550 ° C. for 4 hours in a nitrogen atmosphere. Thereby, the alkyl group contained in the silica layer was removed, and a porous silica layer was formed on the surface of the silica layer. As a result, Pt nanoparticles coated with a porous silica layer via a silica layer were obtained.
[0045] さらにその後、エタノール 7mLに、上記 Ptナノ粒子 210mg及びフエノール榭脂 2 66mgを溶解させたものを一晩攪拌した。これにより、多孔質シリカ層の複数の細孔 内にフエノール榭脂を充填した。その後、真空中、 900°Cで 2時間熱処理して、当該 フエノール榭脂を炭化させた。 [0045] After that, a solution of 210 mg of the Pt nanoparticles and 66 mg of phenol rosin dissolved in 7 mL of ethanol was stirred overnight. As a result, the phenol resin was filled into the plurality of pores of the porous silica layer. Then, the phenol resin was carbonized by heat treatment at 900 ° C. for 2 hours in vacuum.
そして、これを SiOを溶解することができるフッ化水素酸溶液（10%)に浸漬し、シ  Then, it is immersed in a hydrofluoric acid solution (10%) that can dissolve SiO, and
2  2
リカ層及び多孔質シリカ層内の SiOを溶解し除去した。その後、これを 80°Cで乾燥  SiO in the Rica layer and the porous silica layer was dissolved and removed. Then dry it at 80 ° C
2  2
させた。その結果、多孔質シリカ層の無数の細孔内に含浸され炭化された炭素が骨 格をなす多孔質炭素層が形成された。これ〖こより、中空状多孔質炭素層に内包され た Pt触媒（Pt—mhC)を作製した。図 4に、 Pt—mhCの TEM写真を示す。図 4から 、多孔質炭素層とコア部である Ptナノ粒子との間に中空層が形成されて!ヽることが確 f*i¾ れ 。  I let you. As a result, a porous carbon layer formed of carbon impregnated and carbonized in countless pores of the porous silica layer was formed. From this, a Pt catalyst (Pt-mhC) encapsulated in a hollow porous carbon layer was produced. Figure 4 shows a TEM photograph of Pt—mhC. From FIG. 4, it is confirmed that a hollow layer is formed between the porous carbon layer and the Pt nanoparticles as the core part.
[0046] 続いて、上述のようにして作製された、多孔質炭素層に内包された触媒について、 比表面積及び平均細孔径を測定した。比表面積にっ 、ては比表面積測定法 (BET 法）により測定した。また、平均細孔径については細孔径分布測定法 (BJH法）により 解析した。その結果、当該ナノ粒子触媒の多孔質炭素層の比表面積は、 639 [mV g〕であり、その平均細孔径は、 2. lnmであることが分力つた。 [0046] Subsequently, the specific surface area and average pore diameter of the catalyst encapsulated in the porous carbon layer produced as described above were measured. The specific surface area was measured by the specific surface area measurement method (BET method). The average pore size was analyzed by the pore size distribution measurement method (BJH method). As a result, the specific surface area of the porous carbon layer of the nanoparticle catalyst was 639 [mV g], and the average pore diameter was 2. lnm.
また、当該 Ptナノ粒子触媒を用いて-トロベンゼンの水素化反応を行った。その反 応式を以下に示す。  In addition, hydrogenation of -trobenzene was performed using the Pt nanoparticle catalyst. The reaction formula is shown below.
[数 2]
Figure imgf000018_0001
[Equation 2]
Figure imgf000018_0001
ニトロベンゼンをエタノール中に溶解し、 20mlZminの速度で Hガスを供給して、  Nitrobenzene is dissolved in ethanol and H gas is supplied at a rate of 20mlZmin.
2  2
30°Cで 1. 5時間反応を行ったところ、当該ナノ粒子触媒では略 100%の反応効率 が得られた。また、当該触媒を遠心分離により分離 ·回収した後、再び上述と同様水 素化反応を行い反応効率を測定したところ、再利用する前と同様略 100%の反応効 率が得られた。このことから、再利用しても反応効率が低下しないことが分力つた（図 5)。  When the reaction was carried out at 30 ° C for 1.5 hours, a reaction efficiency of about 100% was obtained with the nanoparticle catalyst. Further, after separating and recovering the catalyst by centrifugation, the hydrogenation reaction was performed again in the same manner as described above, and the reaction efficiency was measured. As a result, a reaction efficiency of about 100% was obtained as before reuse. From this, it was found that the reaction efficiency did not decrease even when reused (Fig. 5).
[0048] また、比較例として、有機物により安定ィ匕された Ptナノ粒子 (Pt—PVP)を用いて、 上記水素化反応における反応効率を測定したところ、当該 Pt触媒では、約 80%の 反応効率が得られた。したがって、本発明に係る多孔質炭素層に内包されたナノ粒 子触媒を用いた場合の方が、有機物により安定化された Pt—PVPを用いた場合より 反応効率が高いことが分力つた（図 5)。また、 Pt—PVPでは、分離'回収が困難であ り再利用性の評価は行えな力つた。  [0048] As a comparative example, when the reaction efficiency in the hydrogenation reaction was measured using Pt nanoparticles (Pt-PVP) stabilized with an organic substance, about 80% of the reaction was achieved with the Pt catalyst. Efficiency was obtained. Therefore, it was found that the reaction efficiency was higher when the nanoparticle catalyst encapsulated in the porous carbon layer according to the present invention was used than when using Pt-PVP stabilized by organic matter ( (Figure 5). In addition, Pt-PVP is difficult to separate and collect and cannot be evaluated for reusability.
[0049] また、比較例として、活性炭担持 Pt触媒 (PtZC)を用いて、上記水素化反応にお ける反応効率を測定したところ、当該触媒ナノ粒子では、約 50%の反応効率が得ら れた。したがって、本発明に係る多孔質炭素層に内包された Ptナノ粒子を触媒として 用いた場合の方が、一般的な活性炭担持 Pt触媒 (PtZC)を用いた場合より反応効 率が 2倍程度高 、ことが分力つた（図 5)。  [0049] As a comparative example, when the reaction efficiency in the hydrogenation reaction was measured using an activated carbon-supported Pt catalyst (PtZC), a reaction efficiency of about 50% was obtained with the catalyst nanoparticles. It was. Therefore, the reaction efficiency when using Pt nanoparticles encapsulated in the porous carbon layer according to the present invention as a catalyst is about twice as high as when using a general activated carbon-supported Pt catalyst (PtZC). That was a component (Figure 5).
[0050] また、当該 Ptナノ粒子触媒を用いて酸素の還元反応における電極触媒機能を評 価し 7こ。  [0050] Also, the electrocatalytic function in the oxygen reduction reaction was evaluated using the Pt nanoparticle catalyst.
触媒ナノ粒子とナフイオンが 1： 1となるように調製した水：エタノール ( = 1 : 1)溶液を 、 Ptの量が 14 μ gPt/cm2となるようにグラッシ一カーボン回転リングディスク電極上 に滴下し、乾燥させた。その後、さらに電極上にナフイオンのエタノール溶液 (0. 05 %)を 8. 滴下し、乾燥させた。これを作用電極として用いた。 A water: ethanol (= 1: 1) solution prepared so that the catalyst nanoparticles and naphthions are 1: 1 is dropped onto a glassy carbon rotating ring disk electrode so that the amount of Pt is 14 μgPt / cm2. And dried. After that, naphthion ethanol solution (0. 05 %) Was added dropwise and dried. This was used as a working electrode.
電気化学測定には三電極セルを用い、作用極には触媒をのせたグラッシ一カーボ ン、対極には白金、参照極には銀'塩ィ匕銀を用いた (ルギン細管により、作用極との 電位差を小さくした)。電解質溶液には 0. 1MHC10を用いた。 Oの還元反応は、  A three-electrode cell was used for the electrochemical measurement, a glassy carbon with a catalyst on the working electrode, platinum as the counter electrode, and silver (salt) 匕 silver as the reference electrode. The potential difference of was reduced). As the electrolyte solution, 0.1MHC10 was used. The reduction reaction of O is
4 2  4 2
溶液に Oを 15分間バブリングした後、 Oを流通させながら、 -0. 2Vから 1. OV (vs After bubbling O through the solution for 15 minutes, while flowing O, -0.2 V to 1. OV (vs
2 2  twenty two
. AgZAgCl)まで電位を挿引して測定した。挿引速度は 0. 5V,s 回転速度は 16 OOrpmとした。電極上の汚れを除くため、何度も電位を挿引し、安定したプロットが得 られた後に測定を行った。図 6に示す電流電位曲線から、 0. 5V付近の電位で大きく 負の電流が流れていることが分かる。これは酸素の還元による電流であることから、調 製したカーボンシェルには導電性があり、本触媒は電気化学的な触媒反応にも用い ることが可能であることが明らかになった。  (AgZAgCl) was measured by inserting a potential. The insertion speed was 0.5 V, and the rotation speed was 16 OOrpm. In order to remove contamination on the electrode, the potential was drawn many times, and measurements were taken after a stable plot was obtained. From the current-potential curve shown in Fig. 6, it can be seen that a large negative current flows at a potential in the vicinity of 0.5V. Since this is an electric current due to reduction of oxygen, it was revealed that the prepared carbon shell is conductive, and that this catalyst can be used for electrochemical catalysis.
(実施例 2) (Example 2)
続いて、塩化白金酸 (H PtCl )に代えて、塩ィ匕ロジウム (RhCl )を用いて、触媒を  Subsequently, instead of chloroplatinic acid (H PtCl), using sodium chloride (RhCl), the catalyst was
2 6 3  2 6 3
作製した。 Produced.
まず、 6mMの塩化ロジウム（RhCl )水溶液 5πΛ (30 /ζ πιο1)にエタノール（EtOH  First, a 6 mM aqueous solution of rhodium chloride (RhCl 3) 5πΛ (30 / ζ πιο1) in ethanol (EtOH
3  Three
) 45mLをカロえ、さら〖こ PVP 66mgを添カロし 3時間還流した。その結果、平均粒径 2 . 5nmを有する Rh—PVP(Rh—PVPとは、 Rh粒子が PVPにより被覆されたものを 表す。）が得られた。  ) 45mL was added, and Sarakako PVP 66mg was added and refluxed for 3 hours. As a result, Rh-PVP having an average particle diameter of 2.5 nm (Rh-PVP means that Rh particles are coated with PVP) was obtained.
その後、実施例 1と同様に、 Rh— PVP溶液 4mL (2. 4 μ mol)、トルエン 9mLを混 合した溶液を 3000rpmで 10分遠心分離して、ナノ粒子を沈降させ、上澄み液を除 去した。この沈殿物に、エタノール 30mL、及び NH (28%) 2mL (94mmol)  Thereafter, in the same manner as in Example 1, the solution in which 4 mL (2.4 μmol) of Rh-PVP solution and 9 mL of toluene were mixed was centrifuged at 3000 rpm for 10 minutes to precipitate the nanoparticles, and the supernatant was removed. did. To this precipitate, 30 mL of ethanol and 2 mL (94 mmol) of NH (28%)
3 、 TE 3, TE
OS 0. 2mL (0. 88mmol)を加えて、室温で 6時間撹拌することにより、 TEOSをカロ 水分解'脱水縮合反応させた。この溶液にトルエン 50mLを加え、 3000rpmで 10分 遠心分離し、シリカ層（SiO )で被覆された Rh触媒 (以下、 SiOで被覆された Rh触 By adding 0.2 mL (0.88 mmol) of OS and stirring at room temperature for 6 hours, TEOS was subjected to a water hydrolysis / dehydration condensation reaction. To this solution, add 50 mL of toluene, centrifuge at 3000 rpm for 10 minutes, and apply Rh catalyst coated with silica layer (SiO 2) (hereinafter referred to as Rh catalyst coated with SiO 2).
2 2  twenty two
媒を Rh— SiOと表す。）が得られた。 The medium is represented as Rh—SiO. )was gotten.
2  2
この Rh— SiOにエタノール 30mL、水 2. 0mL、 NH (28%) 2. 55mL (120m  In this Rh-SiO, ethanol 30mL, water 2.0mL, NH (28%) 2.55mL (120m
2 3  twenty three
mol)、 TEOS 0. 4mL (l . 76mmol)及び ODTS 0. 16mLの混合溶液を加えて、 室温で 2時間撹拌することにより、シリカ層の表面をアルキル基 (ォクタデシル基)を 含むシリカ層で被覆した。この溶液にトルエン 70mLを加えて、 3000rpmで 10分遠 心分離し、残渣を 80°Cで乾燥させた。その後、さらに、これを窒素雰囲気下 550°Cで 4時間焼成した。これにより、シリカ層に含まれるアルキル基が除去され、シリカ層の 表面上に多孔質シリカ層が形成された。その結果、シリカ層を介して多孔質シリカ層 で被覆された Rhナノ粒子が得られた。 mol), TEOS 0.4 mL (l.76 mmol) and ODTS 0.16 mL mixed solution, and the mixture is stirred at room temperature for 2 hours to remove the alkyl group (octadecyl group) on the surface of the silica layer. Covered with a containing silica layer. To this solution, 70 mL of toluene was added, and centrifuged at 3000 rpm for 10 minutes, and the residue was dried at 80 ° C. Thereafter, this was further baked at 550 ° C. for 4 hours in a nitrogen atmosphere. Thereby, the alkyl group contained in the silica layer was removed, and a porous silica layer was formed on the surface of the silica layer. As a result, Rh nanoparticles coated with a porous silica layer via a silica layer were obtained.
[0052] さらにその後、エタノール 7mLに、上記 Rhナノ粒子 210mg及びフエノール榭脂 266mgを溶解させたものを一晩攪拌した。これにより、多孔質シリカ層の複数の細孔 内にフエノール榭脂を充填した。その後、真空中、 900°Cで 2時間熱処理して、当該 フエノール榭脂を炭化させた。 [0052] Thereafter, 210 mg of the above Rh nanoparticles and 266 mg of phenol rosin were dissolved in 7 mL of ethanol and stirred overnight. As a result, the phenol resin was filled into the plurality of pores of the porous silica layer. Then, the phenol resin was carbonized by heat treatment at 900 ° C. for 2 hours in vacuum.
そして、これをフッ化水素酸溶液（10%)に浸漬し、シリカ層及び多孔質シリカ層内 の SiOを溶解し除去した。その後、これを 80°Cで乾燥させた。これにより、中空状多 Then, this was immersed in a hydrofluoric acid solution (10%) to dissolve and remove SiO in the silica layer and the porous silica layer. Thereafter, it was dried at 80 ° C. As a result, the hollow
2 2
孔質炭素層に内包された Rh触媒 (Rh— mhC)が作製された。図 7に、 Rh— mhCの TEM写真を示す。図 7から、多孔質炭素層とコア部である Rhナノ粒子との間に中空 層が形成されて ヽることが確認された。  An Rh catalyst (Rh—mhC) encapsulated in a porous carbon layer was fabricated. Figure 7 shows a TEM photograph of Rh-mhC. From FIG. 7, it was confirmed that a hollow layer was formed between the porous carbon layer and the Rh nanoparticles as the core.
[0053] 続いて、当該 Rhナノ粒子触媒を用いてトルエンの水素化反応を行った。その反応 式を以下に示す。 [0053] Subsequently, toluene was hydrogenated using the Rh nanoparticle catalyst. The reaction formula is shown below.
[数 3]  [Equation 3]
Figure imgf000020_0001
Figure imgf000020_0001
上記 Rhナノ粒子触媒 0. 25 molをトルエンを含む溶液に混合し、これに 0. 6M Paの Hガスを供給して、 75°Cで 3時間反応を行った。溶媒としては、デカンを用いた The above Rh nanoparticle catalyst 0.25 mol was mixed with a solution containing toluene, and 0.6 M Pa H gas was supplied thereto, and the reaction was performed at 75 ° C. for 3 hours. As the solvent, decane was used.
2 2
。その結果を表 1に示す。  . The results are shown in Table 1.
[表 1] 触媒 溶媒 TOF[table 1] Catalyst Solvent TOF
Rh-PVP デ刀ン 2.2 29Rh-PVP Desword 2.2 29
R -hmC デカン 25.8 344R -hmC Decane 25.8 344
Rh/C* 、ノ 22.9 156 表 1から、本発明に係る多孔質炭素層に内包された Rhナノ粒子は、原料である Rh - PVPや活性炭担持 Rh触媒 (RhZC * )に比べて反応効率が 2倍以上高 ヽことが分 かった。 Rh / C *, 22.9 156 From Table 1, the Rh nanoparticles encapsulated in the porous carbon layer according to the present invention have a reaction efficiency higher than that of the raw material Rh-PVP and activated carbon-supported Rh catalyst (RhZC *). I found that it was more than twice as high.
続いて、当該 Rhナノ粒子触媒を用いて t一ブチルベンゼンを水素化反応させて、 t ーブチルシクロへキサンの生成を行った。その反応式を褂以下に示す。  Subsequently, t-butylbenzene was hydrogenated using the Rh nanoparticle catalyst to produce t-butylcyclohexane. The reaction formula is shown below.
[数 4] [Equation 4]
Figure imgf000021_0001
Figure imgf000021_0001
上記 Rhナノ粒子触媒 0. 25 molを t一ブチルベンゼンを含む溶液に混合し、こ れに Hガスを供給して、 3時間反応を行った。溶媒としては、メタノールと水を用いた 0.25 mol of the above Rh nanoparticle catalyst was mixed with a solution containing t-butylbenzene, and H gas was supplied thereto, followed by reaction for 3 hours. As the solvent, methanol and water were used.
2 2
oその結果を表 2に示す。 o The results are shown in Table 2.
[表 2] 触媒 溶媒 温度（ °C ) 収率 (％) TOF [Table 2] Catalyst Solvent Temperature (° C) Yield (%) TOF
Rh-PVP メタノ -ル B 0.9 12 Rh-PVP methanol B 0.9 12
Rh-hmC メタノ -ル Ε m 3.2 43  Rh-hmC methanol-m 3.2 43
Rh/C* メタノ- -ル ^/皿 10.1 34  Rh / C * methano-l ^ / dish 10.1 34
Rh-PVP H20 60 1.1 15 Rh-PVP H 2 0 60 1.1 15
R ~hmC H20 60 5.8 20 表 2から、本発明に係る多孔質炭素層に内包された Rhナノ粒子は、原料である Rh -PVPや活性炭担持 Rh触媒 (RhZC)に比べて反応効率が 2倍以上高 ヽことが分か つた。また、溶媒として水を用いても優位な反応性を示すことが確認された。 R ~ hmC H 2 0 60 5.8 20 From Table 2, the reaction efficiency of Rh nanoparticles encapsulated in the porous carbon layer according to the present invention is higher than that of Rh-PVP and activated carbon supported Rh catalyst (RhZC). I found that it was more than twice as high. Moreover, it was confirmed that even when water was used as a solvent, a superior reactivity was exhibited.
(実施例 3) (Example 3)
続いて、塩化白金酸 (H PtCl )に代えて、塩化パラジウム酸 (H PdCl )を用いて、  Subsequently, instead of chloroplatinic acid (H PtCl), using chloropalladium acid (H PdCl),
2 6 2 4 触媒を作製した。  2 6 2 4 A catalyst was prepared.
まず、 2mMの塩化パラジウム酸（H PdCl )水溶液 15π^ (30 /ζ mol)にエタノー  First, add 2mM chloropalladate (H PdCl) aqueous solution 15π ^ (30 / ζ mol) to ethanol
2 4  twenty four
ル（EtOH) 20mL及び水（H O) 15mLをカ卩え、さらに PVP 133mgを添加し 3時間 Add 20 mL of water (EtOH) and 15 mL of water (H 2 O) and add 133 mg of PVP for 3 hours.
2  2
還流した。その結果、平均粒径 1. 3nmを有する Pd— PVP(Pd— PVPとは、 Pd粒子 が PVPにより被覆されたものを表す。）が得られた。 Refluxed. As a result, Pd—PVP having an average particle diameter of 1.3 nm (Pd—PVP means that Pd particles are coated with PVP) was obtained.
その後、実施例 1と同様に、 Pd— PVP溶液 2mL (l. 2 mol)、エタノール 10mL 、トルエン 25mLを混合した溶液を 3000rpmで 10分遠心分離して、ナノ粒子を沈降 させ、上澄み液を除去した。この沈殿物に、エタノール 30mL、及び NH (28%) 2m  After that, in the same manner as in Example 1, the mixture of Pd-PVP solution 2 mL (l. 2 mol), ethanol 10 mL, and toluene 25 mL was centrifuged at 3000 rpm for 10 minutes to precipitate the nanoparticles, and the supernatant was removed. did. To this precipitate, add 30 mL of ethanol and 2 m of NH (28%)
3  Three
L (94mmol)、TEOS 0. 2mL (0. 88mmol)を加えて、室温で 6時間撹拌すること により、 TEOSを加水分解 ·脱水縮合反応させた。この溶液にトルエン 50mLをカロえ、 3000rpmで 10分遠心分離し、シリカ層（SiO )で被覆された Pd触媒 (以下、 SiOで  L (94 mmol) and 0.2 mL (0.88 mmol) of TEOS were added, and the mixture was stirred at room temperature for 6 hours to cause hydrolysis / dehydration condensation reaction of TEOS. To this solution, add 50 mL of toluene, centrifuge at 3000 rpm for 10 minutes, and coat with a silica layer (SiO 2) Pd catalyst (hereinafter referred to as SiO 2).
2 2 被覆された Pd触媒を Pd— SiOと表す。）が得られた。  2 2 The coated Pd catalyst is expressed as Pd-SiO. )was gotten.
2  2
上澄み液を除去後、 Pd— SiOにエタノール 30mL、水 2. OmL、 NH (28%) 2  After removing the supernatant, Pd—SiO with 30 mL ethanol, 2. OmL water, NH (28%) 2
2 3  twenty three
. 55mL (120mmol)、 TEOS 0. 4mL (l. 76mmol)及び ODTS 0. 16mLの混合 溶液を室温で 2時間撹拌することにより、シリカ層の表面をアルキル基 (ォクタデシル 基）を含むシリカ層で被覆した。この溶液にトルエン 70mLをカ卩えて、 3000rpmで 1 0分遠心分離し、残渣を 80°Cで乾燥させた。その後、さらに、これを窒素雰囲気下 55 0°Cで 4時間焼成した。これにより、シリカ層に含まれるアルキル基が除去され、シリカ 層の表面上に多孔質シリカ層が形成された。その結果、シリカ層を介して多孔質シリ 力層で被覆された Pdナノ粒子が得られた。 By stirring a mixed solution of 55 mL (120 mmol), TEOS 0.4 mL (l. 76 mmol) and ODTS 0.16 mL at room temperature for 2 hours, the surface of the silica layer was treated with alkyl groups (octadecyl And a silica layer containing a base). 70 mL of toluene was added to this solution and centrifuged at 3000 rpm for 10 minutes, and the residue was dried at 80 ° C. Thereafter, this was further baked at 550 ° C. for 4 hours in a nitrogen atmosphere. Thereby, the alkyl group contained in the silica layer was removed, and a porous silica layer was formed on the surface of the silica layer. As a result, Pd nanoparticles coated with a porous silica layer through a silica layer were obtained.
さらにその後、メタノール 7mLに、上記 Pdナノ粒子 210mg及びフエノール榭脂 2 66mgを溶解させたものを一晩攪拌した。これにより、多孔質シリカ層の複数の細孔 内にフエノール榭脂を充填した。その後、真空中、 900°Cで 2時間熱処理して、当該 フエノール榭脂を炭化させた。  Thereafter, 210 mg of the Pd nanoparticles and 66 mg of phenol rosin dissolved in 7 mL of methanol were stirred overnight. As a result, the phenol resin was filled into the plurality of pores of the porous silica layer. Then, the phenol resin was carbonized by heat treatment at 900 ° C. for 2 hours in vacuum.
そして、これをフッ化水素酸溶液（10%)に浸漬し、シリカ層及び多孔質シリカ層内 のシリカを溶解し除去した。その後、これを 80°Cで乾燥させた。その結果、上記同様 多孔質炭素層が形成された。これ〖こより、中空状多孔質炭素層に内包された Pd触媒 (Pd—mhC)が作製された。図 8に、 Pd—mhCの TEM写真を示す。図 8力ら、多孔 質炭素層とコア部である Pdナノ粒子との間に中空層が形成されて!ヽることが確認さ れた。  Then, this was immersed in a hydrofluoric acid solution (10%) to dissolve and remove the silica in the silica layer and the porous silica layer. Thereafter, it was dried at 80 ° C. As a result, a porous carbon layer was formed as described above. From this, a Pd catalyst (Pd-mhC) encapsulated in a hollow porous carbon layer was produced. Fig. 8 shows a TEM photograph of Pd-mhC. As shown in Fig. 8, it was confirmed that a hollow layer was formed between the porous carbon layer and the Pd nanoparticles as the core.
(実施例 4) (Example 4)
続いて、塩化白金酸 (H PtCl )に代えて、塩化ルテニウム (RuCl )を用いて、触媒  Then, instead of chloroplatinic acid (H PtCl), ruthenium chloride (RuCl) was used,
2 6 3  2 6 3
を作製した。 Was made.
まず、 6mM塩化ルテニウム（RuCl )水溶液 5mL (30 μ mol)に水（H O) 40mL  First, 5 mL (30 μmol) of 6 mM ruthenium chloride (RuCl) aqueous solution and 40 mL of water (H 2 O)
3 2 3 2
、 PVP 66mgを添加し、さらに水素化ホウ酸ナトリウム（NaBH )水溶液 5mL (300 , 66 mg of PVP, and 5 mL of sodium borohydride (NaBH) aqueous solution (300
4  Four
mol)を加え、 1時間攪拌した。その結果、平均粒径 2nmを有する Ru—PVP(Ru PVPとは、 Ru粒子が PVPにより被覆されたものを表す。）が得られた。  mol) was added and stirred for 1 hour. As a result, Ru—PVP having an average particle diameter of 2 nm (Ru PVP represents a Ru particle coated with PVP) was obtained.
その後、実施例 1と同様に、 Ru— PVP溶液 21111^ ( 1.2 11101)、ェタノール18111レ トルエン 50mLを混合した溶液を 3000rpmで 10分遠心分離して、ナノ粒子を沈降さ せ、上澄み液を除去した。この沈殿物に、エタノール 30mL、及び NH (28%) 2mL  After that, as in Example 1, the mixture of Ru-PVP solution 21111 ^ (1.2 11101) and ethanol 18111 toluene 50 mL was centrifuged at 3000 rpm for 10 minutes to settle the nanoparticles and remove the supernatant. did. Add 30 mL of ethanol and 2 mL of NH (28%) to this precipitate.
3  Three
(94mmol)、 TEOS 0. 2mL (0. 88mmol)をカ卩えて、室温で 6時間撹拌することに より、 TEOSを加水分解.脱水縮合反応させた。この溶液にトルエン 50mLをカ卩え、 3 OOOrpmで 10分遠心分離し、シリカ層（SiO )で被覆された Ru触媒 (以下、 SiOで 被覆された Ru触媒を Ru— SiOと表す。）が得られた。 (94 mmol) and TEOS (0.2 mL, 0.88 mmol) were added, and the mixture was stirred at room temperature for 6 hours to cause hydrolysis and dehydration condensation of TEOS. To this solution, add 50 mL of toluene, centrifuge at 3 OOOrpm for 10 minutes, and Ru catalyst coated with silica layer (SiO 2) (hereinafter referred to as SiO The coated Ru catalyst is represented as Ru—SiO. )was gotten.
2  2
[0057] その後、 Ru—SiOの懸濁液にエタノール 30mL、水 2. OmL、 NH (28%) 2. 5  [0057] Then, 30 mL of ethanol, 2. OmL of water, NH (28%) 2.5 in a suspension of Ru-SiO
2 3  twenty three
5mL (120mmol)、TEOS 0. 4mL (l. 76mmol)及び ODTS 0. 16mLの混合溶 液を室温で 2時間撹拌することにより、シリカ層の表面をアルキル基 (ォクタデシル基 )を含むシリカ層で被覆した。この溶液にトルエン 70mLをカ卩えて、 3000rpmで 10 分遠心分離し、残渣を 80°Cで乾燥させた。その後、さらに、これを窒素雰囲気下 550 °Cで 4時間焼成した。これにより、シリカ層に含まれるアルキル基が除去され、シリカ 層の表面上に多孔質シリカ層が形成された。その結果、シリカ層を介して多孔質シリ 力層で被覆された Ruナノ粒子が得られた。  The surface of the silica layer is coated with a silica layer containing an alkyl group (octadecyl group) by stirring a mixed solution of 5 mL (120 mmol), TEOS 0.4 mL (l. 76 mmol) and ODTS 0.16 mL at room temperature for 2 hours. did. 70 mL of toluene was added to this solution and centrifuged at 3000 rpm for 10 minutes, and the residue was dried at 80 ° C. Thereafter, this was further calcined at 550 ° C. for 4 hours in a nitrogen atmosphere. Thereby, the alkyl group contained in the silica layer was removed, and a porous silica layer was formed on the surface of the silica layer. As a result, Ru nanoparticles coated with a porous silica force layer via a silica layer were obtained.
[0058] さらにその後、メタノール 7mLに、上記 Ruナノ粒子 210mg及びフエノール榭脂 2 66mgを溶解させたものを一晩攪拌した。これにより、多孔質シリカ層の複数の細孔 内にフエノール榭脂を充填した。その後、真空中、 900°Cで 2時間熱処理して、当該 フエノール榭脂を炭化させた。 [0058] After that, 210 mg of the above Ru nanoparticles and 66 mg of phenol resin were dissolved in 7 mL of methanol and stirred overnight. As a result, the phenol resin was filled into the plurality of pores of the porous silica layer. Then, the phenol resin was carbonized by heat treatment at 900 ° C. for 2 hours in vacuum.
そして、これをフッ化水素酸溶液（10%)に浸漬し、シリカ層及び多孔質シリカ層内 のシリカを溶解し除去した。その後、これを 80°Cで乾燥させた。その結果、上記同様 多孔質炭素層が形成された。これ〖こより、中空状多孔質炭素層に内包された触媒 (R u—mhC)が作製された。図 9に、 Ru—mhCの TEM写真を示す。図 9力ら、多孔質 炭素層が形成されていることが確認された。また、コア部である Ruナノ粒子は、非常 に微小であるため、当該コア部は目視できな力つた。  Then, this was immersed in a hydrofluoric acid solution (10%) to dissolve and remove the silica in the silica layer and the porous silica layer. Thereafter, it was dried at 80 ° C. As a result, a porous carbon layer was formed as described above. From this, a catalyst (R u-mhC) encapsulated in a hollow porous carbon layer was produced. Figure 9 shows a TEM photograph of Ru-mhC. As shown in Fig. 9, it was confirmed that a porous carbon layer was formed. In addition, since the Ru nanoparticles, which are the core part, are very small, the core part has a force that cannot be visually observed.
(実施例 5)  (Example 5)
続いて、塩化白金酸 (H PtCl )に代えて、塩ィ匕金酸 (HAuCl )を用いて、触媒を  Subsequently, instead of chloroplatinic acid (H PtCl), chloroplatinic acid (HAuCl) was used to
2 6 4  2 6 4
作製した。  Produced.
まず、 10mMの塩化金酸（HAuCl )水溶液 5πΛ (50 /ζ πιο1)に水（H 0) 45mL、  First, 10mL of chloroauric acid (HAuCl) aqueous solution 5πΛ (50 / ζ πιο1) and water (H 0) 45mL,
4 2 さらに PVP 558mgを添カ卩し、 0度で 30分撹拌し、さらに水素化ホウ酸ナトリウム (Na BH )水溶液 5πΛ (500 /ζ πιο1)をカ卩え、 30分攪拌した。その結果、平均粒径 1. 3η 4 2 Further, 558 mg of PVP was added, and the mixture was stirred at 0 ° C. for 30 minutes. Further, an aqueous solution of sodium borohydride (Na BH) 5πΛ (500 / ζ πιο1) was added and stirred for 30 minutes. As a result, the average particle size 1.3 η
4 Four
mを有する Au—PVP(Au—PVPとは、 Au粒子が PVPにより被覆されたものを表す 。）が得られた。  Au-PVP having m (Au-PVP represents Au particles coated with PVP) was obtained.
その後、 Au—PVP溶液 5mL (5 μ mol)にアセトン 40mLを混合した溶液を 1500 Orpmで 20分遠心分離して、ナノ粒子を沈降させ、上澄み液を除去した。この沈殿物 【こ、エタノーノレ 30mL、及び NH (28%) 2.56mL (120mmol)、 TEOS 0. lmL (0 After that, add 5 mL (5 μmol) of Au-PVP solution and 40 mL of acetone to 1500 mL. Centrifugation at Orpm for 20 minutes allowed the nanoparticles to settle and remove the supernatant. This precipitate [this, ethanol, 30mL, NH (28%) 2.56mL (120mmol), TEOS 0.lmL (0
3  Three
. 44mmol)を加えて、室温で 19時間撹拌することにより、 TEOSを加水分解 '脱水 縮合反応させた。この溶液を 15000rpmで 20分遠心分離し、シリカ層（SiO )で被  44 mmol) was added and the mixture was stirred at room temperature for 19 hours to hydrolyze and dehydrate and condense TEOS. This solution is centrifuged at 15000 rpm for 20 minutes and covered with a silica layer (SiO 2).
2 覆された Au触媒 (以下、 SiOで被覆された Au触媒を Au— SiOと表す。）が得られ  2 A covered Au catalyst (hereinafter, the Au catalyst coated with SiO is referred to as Au-SiO) is obtained.
2 2  twenty two
た。  It was.
[0059] 上澄み液を除去後、 Au-SiOにエタノール 30mL、水 2. OmL、 NH (28%) 1  [0059] After removing the supernatant, 30 mL of ethanol, 2. OmL of water, NH (28%) in Au-SiO 1
2 3  twenty three
. 28mL (60mmol)、TEOS 0. lmL (0. 44mmol)及び ODTS 0. 04mLの混合 溶液を室温で 2時間撹拌することにより、シリカ層の表面をアルキル基 (ォクタデシル 基)を含むシリカ層で被覆した。この溶液を 15000rpmで 20分遠心分離し、残渣を 8 0°Cで乾燥させた。その後、さらに、これを窒素雰囲気下 550°Cで 4時間焼成した。こ れにより、シリカ層に含まれるアルキル基が除去され、シリカ層の表面上に多孔質シリ 力層が形成された。その結果、シリカ層を介して多孔質シリカ層で被覆された Auナノ 粒子が得られた。  28 mL (60 mmol), TEOS 0.1 mL (0.44 mmol) and ODTS 0.04 mL mixed solution was stirred at room temperature for 2 hours to coat the surface of the silica layer with a silica layer containing an alkyl group (octadecyl group). did. This solution was centrifuged at 15000 rpm for 20 minutes, and the residue was dried at 80 ° C. Thereafter, this was further baked at 550 ° C. for 4 hours in a nitrogen atmosphere. As a result, the alkyl group contained in the silica layer was removed, and a porous silicon force layer was formed on the surface of the silica layer. As a result, Au nanoparticles coated with a porous silica layer through a silica layer were obtained.
[0060] さらにその後、メタノール 7mLに、上記 Auナノ粒子 210mg及びフエノール榭脂 2 66mgを溶解させたものを一晩攪拌した。これにより、多孔質シリカ層の複数の細孔 内にフエノール榭脂を充填した。その後、真空中、 900°Cで 2時間熱処理して、当該 フエノール榭脂を炭化させた。  [0060] After that, 210 mg of the above Au nanoparticles and 66 mg of phenol resin were dissolved in 7 mL of methanol and stirred overnight. As a result, the phenol resin was filled into the plurality of pores of the porous silica layer. Then, the phenol resin was carbonized by heat treatment at 900 ° C. for 2 hours in vacuum.
そして、これをフッ化水素酸溶液（10%)に浸漬し、シリカ層及び多孔質シリカ層内 のシリカを溶解し除去した。その後、これを 80°Cで乾燥させた。その結果、上記同様 多孔質炭素層が形成された。これ〖こより、中空状多孔質炭素層に内包された Au触 媒 (Au— mhC)が作製された。図 10に、 Au— mhCの TEM写真を示す。図 10から 、多孔質炭素層とコア部である Auナノ粒子との間に中空層が形成されて!ヽることが 確認された。  Then, this was immersed in a hydrofluoric acid solution (10%) to dissolve and remove the silica in the silica layer and the porous silica layer. Thereafter, it was dried at 80 ° C. As a result, a porous carbon layer was formed as described above. From this, an Au catalyst (Au—mhC) encapsulated in a hollow porous carbon layer was produced. Figure 10 shows a TEM photograph of Au-mhC. From FIG. 10, it was confirmed that a hollow layer was formed between the porous carbon layer and the Au nanoparticles as the core part.

Claims

請求の範囲 The scope of the claims
[1] 触媒粒子を含むコア部と、前記コア部を覆うように形成された多孔質炭素層とを含 む触媒を製造する方法であって、  [1] A method for producing a catalyst comprising a core part containing catalyst particles and a porous carbon layer formed so as to cover the core part,
前記コア部を覆うようにシリカ含有層を形成する第一工程と、  A first step of forming a silica-containing layer so as to cover the core part;
前記シリカ含有層を覆うように前記多孔質炭素層を形成する第二工程と、 前記シリカ含有層を除去する第三工程と、  A second step of forming the porous carbon layer so as to cover the silica-containing layer; a third step of removing the silica-containing layer;
を包含する触媒製造方法。  The catalyst manufacturing method including this.
[2] 前記第二工程は、  [2] The second step includes
前記シリカ含有層を覆うように多孔質シリカ含有層を形成する工程と、  Forming a porous silica-containing layer so as to cover the silica-containing layer;
前記多孔質シリカ含有層の少なくとも一部に炭素源を充填する工程と、 前記炭素源を炭化することによって、前記多孔質炭素層を形成する工程と、 を包含する、請求項 1に記載の触媒製造方法。  The catalyst according to claim 1, comprising: filling at least a part of the porous silica-containing layer with a carbon source; and forming the porous carbon layer by carbonizing the carbon source. Production method.
[3] 前記多孔質シリカ含有層を形成する工程は、  [3] The step of forming the porous silica-containing layer includes:
アルキル基を含むシリコンアルコキシドまたはクロライド（Si (X) (R) (Xは C1または  Silicon alkoxides or chlorides containing alkyl groups (Si (X) (R) (where X is C1 or
m n  m n
OR' (R，はアルキル基）、 Rはアルキル基であり、 m= 1〜3、 n= 1〜3、 n/m= 1/ 3〜3を満たす。 Rに置換基を含んでもよい。；)）の加水分解 ·脱水縮合反応、または 前記シリコンアルコキシドまたは前記クロライドとアルコキシシラン（Si ( OR) (Rはァ  OR ′ (R is an alkyl group), R is an alkyl group, and satisfies m = 1 to 3, n = 1 to 3, and n / m = 1/3 to 3. R may contain a substituent. ;)) Hydrolysis · dehydration condensation reaction, or the silicon alkoxide or chloride and alkoxysilane (Si (OR) (R is
4 ルキル基) )との加水分解 '脱水縮合反応により、アルキル基包有シリカ層を形成する 工程と、  (4) alkyl group))) hydrolysis with 'dehydration condensation reaction to form an alkyl group-containing silica layer;
前記アルキル基包有シリカ層からアルキル基を分解除去する工程と、  Decomposing and removing alkyl groups from the alkyl group-containing silica layer;
を包含する、請求項 2に記載の触媒製造方法。  The method for producing a catalyst according to claim 2, comprising:
[4] 前記第三工程は、  [4] The third step includes
前記シリカ含有層および前記多孔質シリカ含有層に包有されるシリカを溶解すること によって、前記シリカ含有層および前記多孔質シリカ含有層を除去する工程を包含 する、請求項 2に記載の触媒製造方法。  3. The catalyst production according to claim 2, comprising a step of removing the silica-containing layer and the porous silica-containing layer by dissolving silica included in the silica-containing layer and the porous silica-containing layer. Method.
[5] 前記第三工程は、  [5] The third step includes
前記シリカをフッ化水素酸溶液およびアルカリ溶液のうちの少なくとも一方により溶解 することによって、前記シリカ含有層および前記多孔質シリカ含有層を除去する工程 を包含する、請求項 4に記載の触媒製造方法。 Removing the silica-containing layer and the porous silica-containing layer by dissolving the silica in at least one of a hydrofluoric acid solution and an alkaline solution. The method for producing a catalyst according to claim 4, comprising:
[6] 前記炭素源は、フエノール榭脂、ポリアクリルアミド、ポリピロール、またはグルコース[6] The carbon source is phenol rosin, polyacrylamide, polypyrrole, or glucose
、スクロース、フルフリルアルコールなどの重合体、石油ピッチから選択される少なくと も 1つである、請求項 2に記載の触媒製造方法。 3. The method for producing a catalyst according to claim 2, wherein the catalyst is at least one selected from polymers such as sucrose and furfuryl alcohol, and petroleum pitch.
[7] 触媒粒子を含むコア部と、 [7] a core portion containing catalyst particles;
前記コア部を覆うように形成された多孔質炭素層と  A porous carbon layer formed to cover the core portion;
を含む触媒であって、  A catalyst comprising:
前記コア部と前記多孔質炭素層との間には、中空層が設けられてなる触媒。  A catalyst in which a hollow layer is provided between the core portion and the porous carbon layer.
[8] 前記触媒粒子は、鉄 (Fe)、ルテニウム (Ru)、コバルト (Co)、ロジウム (Rh)、イリジゥ ム（Ir)、ニッケル (Ni)、パラジウム ば、白金（Pt)、銅（Cu)、銀 (Ag)、アルミニウム（[8] The catalyst particles include iron (Fe), ruthenium (Ru), cobalt (Co), rhodium (Rh), iridium (Ir), nickel (Ni), palladium, platinum (Pt), copper (Cu ), Silver (Ag), aluminum (
A1)、チタン (Ti)、すず (Sn)、ニオブ (Nb)およびタングステン (W)力もなる群力も選 択される少なくとも 1つを含む、請求項 7に記載の触媒。 The catalyst according to claim 7, comprising at least one selected from A1), titanium (Ti), tin (Sn), niobium (Nb) and tungsten (W) forces.
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