WO2009116157A1 - Process for producing catalyst for fuel cell, electrode assembly, and fuel cell - Google Patents

Process for producing catalyst for fuel cell, electrode assembly, and fuel cell Download PDF

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Publication number
WO2009116157A1
WO2009116157A1 PCT/JP2008/055145 JP2008055145W WO2009116157A1 WO 2009116157 A1 WO2009116157 A1 WO 2009116157A1 JP 2008055145 W JP2008055145 W JP 2008055145W WO 2009116157 A1 WO2009116157 A1 WO 2009116157A1
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Prior art keywords
fuel cell
catalyst
producing
fibrous nanocarbon
metal catalyst
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PCT/JP2008/055145
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French (fr)
Japanese (ja)
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勲 持田
聖昊 尹
聖和 洪
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住友商事株式会社
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Priority to JP2010503710A priority Critical patent/JPWO2009116157A1/en
Priority to PCT/JP2008/055145 priority patent/WO2009116157A1/en
Publication of WO2009116157A1 publication Critical patent/WO2009116157A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8817—Treatment of supports before application of the catalytic active composition
    • 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
    • B01J21/185—Carbon nanotubes
    • 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
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/8906—Iron and noble 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
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/892—Nickel and noble 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
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/03—Precipitation; Co-precipitation
    • B01J37/031—Precipitation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/9075—Catalytic material supported on carriers, e.g. powder carriers
    • H01M4/9083—Catalytic material supported on carriers, e.g. powder carriers on carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/92—Metals of platinum group
    • H01M4/925—Metals of platinum group supported on carriers, e.g. powder carriers
    • H01M4/926—Metals of platinum group supported on carriers, e.g. powder carriers on carbon or graphite
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/03—Particle morphology depicted by an image obtained by SEM
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Definitions

  • the present invention relates to a method for producing a fuel cell catalyst, an electrode assembly, and a fuel cell.
  • Non-Patent Document 1 a fuel cell catalyst having a structure in which noble metal catalyst particles are supported on fibrous nanocarbon having tunnel-type mesopores is known (for example, see Non-Patent Document 1).
  • FIG. 11 is a flowchart shown for explaining a conventional method of manufacturing a fuel cell catalyst described in Non-Patent Document 1.
  • FIG. 12 is a view for explaining a tunnel-type mesopore forming step S930 in the conventional method for producing a fuel cell catalyst.
  • FIG. 12A is a diagram showing a reaction surface in fibrous nanocarbon
  • FIG. 12B is a diagram showing a change in the bonding state of carbon.
  • the conventional method for producing a catalyst for a fuel cell includes a fibrous nanocarbon production step S910 for producing a fibrous nanocarbon having a herringbone structure or a fibrous nanocarbon having a platelet structure, A new catalyst particle attaching step S920 for attaching new catalyst particles to the surface of the fibrous nanocarbon, and contacting the fibrous nanocarbon with hydrogen gas in a temperature range of 600 ° C. to 1200 ° C.
  • a tunnel type mesopore forming step S930 for forming pores and a noble metal catalyst particle supporting step S940 for supporting noble metal catalyst particles such as PtRu in the tunnel type mesopores are included in this order.
  • the nanorod constituting the fibrous nanocarbon is selected partially and by using a novel catalytic gasification method using hydrogen gas.
  • tunnel type mesopores having an average pore diameter of about 3 nm to 10 nm are formed.
  • the present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing a fuel cell catalyst capable of obtaining higher fuel cell efficiency than conventional ones. Moreover, it aims at providing the electrode assembly manufactured using the catalyst for fuel cells manufactured by such a method, and a fuel cell.
  • the present inventors have formed tunnel-type mesopores in fibrous nanocarbons using an oxidizing gas. As a result, a large amount of oxygen functional groups are formed on the pore walls, so that a larger amount of noble metal catalyst particles can be supported in the tunnel-type mesopores, resulting in higher fuel cell efficiency than before.
  • the present invention has been completed.
  • the method for producing a fuel cell catalyst of the present invention comprises a fibrous nanocarbon by thermally decomposing a carbon-containing gas in the temperature range of 400 ° C. to 1200 ° C. in the presence of a metal catalyst or an alloy catalyst.
  • a tunnel-type mesopore forming step for forming a tunnel-type mesopore in the fibrous nanocarbon by contacting an oxidizing gas with the nanocarbon, and a noble-metal catalyst particle support for supporting a noble-metal catalyst particle in the tunnel-type mesopore The steps are included in this order.
  • the fibrous nanocarbon has a large average particle diameter of 2 nm. It becomes possible to disperse and carry fine noble metal catalyst particles of about ⁇ 5 nm, and as a result, high fuel cell efficiency can be obtained.
  • tunnel mesopores are formed in the fibrous nanocarbon using an oxidizing gas in the tunnel-type mesopore forming step.
  • a large amount of oxygen functional groups are formed on the pore walls of the type mesopores. For this reason, it becomes possible to carry
  • a fuel cell catalyst capable of obtaining higher fuel cell efficiency than before can be produced.
  • a catalyst for a fuel cell of the present invention it becomes possible to form tunnel-type mesopores in fibrous nanocarbon at a temperature lower than that in the past, so that fuel can be produced at a lower production cost than in the past.
  • a battery catalyst can be produced.
  • the fibrous nanocarbon produced in the fibrous nanocarbon production step is a fibrous nanocarbon having a herringbone structure or a fibrous nanocarbon having a platelet structure. Carbon is preferred.
  • the fibrous nanocarbon having a herringbone structure or the fibrous nanocarbon having a platelet structure has an axial width D (see FIG. 2C described later) of nanorods constituting these fibrous nanocarbons, for example, 2. It is about 5 nm. Therefore, by using the above-described method, a tunnel-type mesopore capable of supporting a large amount of fine noble metal catalyst particles having an average particle diameter of about 2 nm to 5 nm dispersed in fibrous nanocarbon can be formed. Is possible.
  • the noble metal catalyst particles have an average particle diameter in the range of 2 nm to 5 nm, and the tunnel-type mesopores have an average pore diameter of 2.5 nm to 100 nm. It is preferable that the average depth is in the range of 10 nm or more.
  • fine noble metal catalyst particles having an average particle diameter of about 2 nm to 5 nm can be reliably supported in the tunnel type mesopores.
  • the iron-based transition metal catalyst particles preferably have an average particle size in the range of 2.5 nm to 100 nm.
  • tunnel-type mesopores having an average pore diameter in the range of 2.5 nm to 100 nm, in other words, fine noble metal catalyst particles having an average particle diameter of about 2 to 5 nm. Possible tunnel-type mesopores can be formed.
  • the fibrous nanocarbon produced at the said fibrous nanocarbon preparation process has a BET specific surface area of 200 m ⁇ 2 > / g or more.
  • the oxidizing gas is preferably air, a mixed gas of inert gas and oxygen gas, or pure oxygen gas.
  • the fibrous nanocarbon after the completion of the tunnel-type mesopore formation step contains 0.5 wt% to 20 wt% oxygen. Is preferred.
  • the iron-based transition metal catalyst particles are preferably composed of fine particles of Fe, Ni, Co, or an alloy thereof.
  • the noble metal catalyst particles are preferably composed of fine particles of Pt, Ru or Pd or an alloy containing these noble metals.
  • the electrode assembly of the present invention is a fuel cell catalyst produced from a slurry obtained by mixing a carbon-containing paste with a fuel cell catalyst produced by the method for producing a fuel cell catalyst of the invention.
  • the ratio of the total weight of the noble metal catalyst particles to the sum of the total weight of the noble metal catalyst particles and the total weight of carbon in the slurry is 40% or less.
  • the electrode assembly of the present invention is an electrode assembly manufactured from a slurry obtained by mixing a carbon-containing paste with a fuel cell catalyst manufactured by the method for manufacturing a fuel cell catalyst of the present invention, In other words, the electrode assembly can obtain high fuel cell efficiency.
  • the electrode assembly of the present invention can make the amount of precious metal used about 80% or more, but by making the amount of precious metal used 40% or less, the amount of precious metal catalyst particles used is small and the production cost is low. It becomes a relatively inexpensive electrode assembly.
  • the fuel cell of the present invention is characterized in that it can produce electric power of 160 mW / cm 2 or more during operation at 90 ° C.
  • the fuel cell of the present invention is a fuel cell including the above-described electrode assembly, as is clear from the examples described later, the amount of noble metal catalyst particles used is small and the manufacturing cost is relatively low. However, the fuel cell can achieve a predetermined fuel cell efficiency.
  • the fuel cell of the present invention is characterized in that it can produce electric power of 185 mW / cm 2 or more during operation at 90 ° C.
  • the fuel cell of the present invention is a fuel cell including the above-described electrode assembly, as is clear from the examples described later, the amount of noble metal catalyst particles used is small and the manufacturing cost is relatively low. However, the fuel cell can achieve a predetermined fuel cell efficiency.
  • FIG. It is a flowchart shown in order to demonstrate the manufacturing method of the catalyst for fuel cells which concerns on embodiment. It is a figure shown in order to demonstrate the structure of fibrous nanocarbon 100.
  • FIG. It is a figure shown in order to demonstrate the manufacturing method of the catalyst for fuel cells which concerns on embodiment. It is a figure shown in order to demonstrate the manufacturing method of the catalyst for fuel cells which concerns on embodiment. It is a figure shown in order to demonstrate the catalyst 100b for fuel cells which concerns on embodiment. It is a figure shown in order to demonstrate the cell evaluation system 200.
  • FIG. It is a figure which shows the power density which the catalyst for fuel cells which concerns on the comparative example 1 produces. It is a figure which shows the power density which the catalyst for fuel cells which concerns on the comparative example 2 produces.
  • FIG. 1 is a flowchart showing a method for manufacturing a fuel cell catalyst according to an embodiment.
  • FIG. 2 is a diagram shown for explaining the structure of the fibrous nanocarbon 100 after completion of the fibrous nanocarbon production step S10.
  • 2 (a) is a diagram showing one fibrous nanocarbon 100 schematically
  • FIG. 2 (b) is an enlarged view of a portion indicated by reference sign A 1 in FIG. 2 (a)
  • 2 ( c) is an enlarged view of the nanorod 106.
  • FIG. 1 is a flowchart showing a method for manufacturing a fuel cell catalyst according to an embodiment.
  • FIG. 2 is a diagram shown for explaining the structure of the fibrous nanocarbon 100 after completion of the fibrous nanocarbon production step S10.
  • 2 (a) is a diagram showing one fibrous nanocarbon 100 schematically
  • FIG. 2 (b) is an enlarged view of a portion indicated by reference sign A 1 in FIG. 2 (a)
  • 2 ( c) is an enlarged view of the nanorod 106.
  • FIG. 3 and FIG. 4 are diagrams for explaining a method of manufacturing a fuel cell catalyst according to the embodiment.
  • FIG. 3A is a diagram showing the structure of the fibrous nanocarbon 100 after the completion of the fibrous nanocarbon production step S10
  • FIG. 3B is the fibrous nanocarbon after the completion of the iron-based transition metal catalyst particle attaching step S20.
  • FIG. 3 (c), FIG. 3 (d), and FIG. 4 (a) are diagrams showing the structure of fibrous nanocarbon 100 during tunnel-type mesopore formation step S30.
  • 4 (b) is a diagram showing the structure of the fibrous nanocarbon 100 after the iron-based transition metal catalyst particles 110 are removed after the tunnel-type mesopore forming step S30 is completed, and
  • FIG. 4 (c) is the noble metal catalyst particles. It is a figure which shows the structure of fibrous nanocarbon 100 after completion
  • FIG. 5 is a view for explaining the fuel cell catalyst 100b according to the embodiment.
  • FIG. 5A is a transmission electron microscope photograph of the fuel cell catalyst 100b
  • FIG. 5B is an enlarged photograph of FIG. 5A.
  • the method for producing a fuel cell catalyst includes a fibrous nanocarbon production step S10, an iron-based transition metal catalyst particle adhesion step S20, a tunnel-type mesopore formation step S30, and a noble metal.
  • the catalyst particle supporting step S40 is included in this order.
  • each process will be described in detail.
  • Fibrous nanocarbon production process S10 is a step of producing fibrous nanocarbon 100 by subjecting a carbon-containing gas to a thermal decomposition reaction in the temperature range of 400 ° C. to 1200 ° C. in the presence of a metal catalyst or an alloy catalyst. Yes (see FIG. 3A).
  • the metal catalyst or alloy catalyst a transition metal such as iron, nickel, cobalt, or a catalyst produced from an alloy thereof (for example, iron nitrate, nickel nitrate, etc.) is used.
  • the carbon-containing gas carbon monoxide (CO) or hydrocarbon (for example, methane (CH 3 ), ethylene (C 2 H 4 ), propane (C 3 H 8 ), etc.) is used.
  • Hydrogen hydrogen partial pressure of 0% to 90%
  • the thermal decomposition reaction is performed by bringing the above-mentioned carbon-containing gas into contact with the above-described metal catalyst or alloy catalyst in a temperature range of 400 ° C. to 1200 ° C.
  • the arrangement angle of the nanorod group is more than 20 degrees with respect to the axis perpendicular to the fiber axis in the nanorod stacking direction. It is a fibrous nanocarbon having a herringbone structure arranged at an angle of largely less than 80 degrees.
  • the nanorod group has a structure in which a large number of nanorods 106 are arranged in parallel to each other.
  • the nanorod 106 has a hexagonal column shape and a structure in which carbon hexagonal mesh surfaces are stacked concentrically.
  • reference numeral 102 indicates a metal catalyst or alloy catalyst
  • reference numeral 104 indicates a structure in which a number of nanorods 106 are arranged in parallel to each other.
  • the short diameter Wa of the metal catalyst or alloy catalyst 102 is, for example, 50 to 150 nm
  • the long diameter Wb of the metal catalyst or alloy catalyst 102 is, for example, 50 nm to 300 nm.
  • the axial width D of the nanorod 106 illustrated in FIG. 2C is, for example, 2.5 nm
  • the length L of the nanorod 106 is, for example, 20 nm.
  • the length of the fibrous nanocarbon 100 is, for example, 500 nm to 3000 nm.
  • Iron-based transition metal catalyst particle adhesion step S20 The iron-based transition metal catalyst particle attaching step S20 is a step of attaching the iron-based transition metal catalyst particles 110 to the surface of the fibrous nanocarbon 100 (see FIG. 3B).
  • the iron-based transition metal catalyst particle adhering step S20 is performed by immersing the fibrous nanocarbon 100 in a solution containing the iron-based transition metal catalyst particles 110, and then drying the fibrous nanocarbon 100.
  • the iron-based transition metal catalyst particles 110 those composed of fine particles of Fe, Ni, Co, or alloys thereof are used. Further, as the iron-based transition metal catalyst particles 110, those having an average particle diameter in the range of 2.5 nm to 100 nm are used.
  • tunnel type mesopore forming step S30 is a step of forming the tunnel-type mesopores 120 in the fibrous nanocarbon 100 by contacting the fibrous nanocarbon 100 with an oxidizing gas in a temperature range of 200 ° C. to 600 ° C. (See FIG. 3C, FIG. 3D, and FIG. 4A.)
  • the oxidizing gas for example, air, a mixed gas of inert gas and oxygen gas, or pure oxygen gas is used.
  • the tunnel-type mesopores grow gradually as the contact time elapses, so that the average pore diameter is in the range of 2.5 nm to 100 nm, and the axial direction B of the nanorod 106 (FIG. 4).
  • Tunnel type mesopores having an average length (average depth) of 10 nm or more along (b) and FIG. 2B) can be formed with good controllability.
  • the noble metal catalyst particle supporting step S40 is a step of supporting the noble metal catalyst particles 130 in the tunnel-type mesopores 120 (see FIGS. 4B to 4D).
  • the noble metal catalyst particle supporting step S40 is performed by removing the iron-based transition metal catalyst particles 110 from the fibrous nanocarbon 100 and then immersing the fibrous nanocarbon 100 in a solution containing the noble metal catalyst particles 130.
  • the noble metal catalyst particles 130 those made of fine particles of Pt, Ru, Pd, or an alloy containing these noble metals are used. Further, as the noble metal catalyst particles 130, those having an average particle diameter in the range of 2 nm to 5 nm are used.
  • a fuel cell catalyst 140 having a structure in which a large number of noble metal catalyst particles 130 are supported in the tunnel type mesopores 120 is obtained (FIGS. 4C and 4D) and FIG. (See FIG. 5A and FIG. 5B.)
  • the fuel cell catalyst 140 according to the embodiment can be manufactured as described above.
  • an electrode assembly can be manufactured using the slurry obtained by mixing a carbon containing paste with the catalyst 140 for fuel cells manufactured in this way.
  • a fuel cell can be manufactured using the electrode assembly manufactured in this way.
  • the tunnel-type mesopores in the fibrous nanocarbon 100 Since noble metal catalyst particles 130 are supported in 120, a large amount of fine noble metal catalyst particles 130 having an average particle diameter of about 2 nm to 5 nm can be dispersed and supported on the fibrous nanocarbon 100. As a result, high fuel cell efficiency can be obtained.
  • the tunnel-type mesopores 120 are formed in the fibrous nanocarbon 100 using the oxidizing gas in the tunnel-type mesopore formation step S30.
  • a large amount of oxygen functional groups are formed on the pore walls of the tunnel-type mesopores 120 to be formed. For this reason, it becomes possible to make the fibrous nanocarbon 100 carry a larger amount of the noble metal catalyst 130 than before.
  • a fuel cell catalyst according to the embodiment, it is possible to form the tunnel mesopores 120 in the fibrous nanocarbon 100 at a temperature lower than that of the conventional method, and therefore, the manufacturing cost is lower than that of the conventional method.
  • a fuel cell catalyst can be produced at low cost.
  • the fibrous nanocarbon 100 produced in the fibrous nanocarbon production step S10 is a fibrous nanocarbon having a herringbone structure, the fibrous nanocarbon. It is possible to form a tunnel-type mesopore 120 capable of dispersing and supporting a large amount of fine noble metal catalyst particles having an average particle diameter of about 2 nm to 5 nm.
  • the noble metal catalyst particles 130 have an average particle diameter in the range of 2 nm to 5 nm, and the tunnel-type mesopores 120 have an average pore diameter of 2.5 nm to Since it is in the range of 100 nm and the average depth is in the range of 10 nm or more, minute noble metal catalyst particles 130 having an average particle diameter of about 2 nm to 5 nm can be supported in the tunnel type mesopores 120.
  • the average pore diameter is 2.5 nm to 100 nm.
  • the tunnel-type mesopores 120 within the range that is, the tunnel-type mesopores capable of supporting a large amount of fine noble metal catalyst particles 130 having an average particle diameter of about 2 nm to 5 nm can be formed.
  • the fibrous nanocarbon 100 produced in the fibrous nanocarbon production step S10 has a BET specific surface area of 200 m 2 / g or more.
  • a large amount of noble metal catalyst particles 130 can be supported on the carbon 100.
  • the oxidizing gas is air, a mixed gas of inert gas and oxygen gas, or pure oxygen gas, so It is possible to introduce the oxygen functional group.
  • the fibrous nanocarbon 100 after the completion of the tunnel-type mesopore forming step S30 contains 0.5 wt% to 20 wt% of oxygen. Therefore, the noble metal catalyst particles 130 can be stably supported in the tunnel type mesopores 120.
  • the iron-based transition metal catalyst particles 110 are made of fine particles of Fe, Ni, Co, or an alloy thereof. It is possible to form the tunnel-type mesopores 120 as described above in carbon.
  • Example 1 Implementing a method for producing a catalyst for a fuel cell comprising the following fibrous nanocarbon production step, iron-based transition metal catalyst particle adhesion step, tunnel-type mesopore formation step, and noble metal catalyst particle support step in this order Thus, a fuel cell catalyst according to Example 1 was produced.
  • Fibrous nanocarbon was prepared.
  • Tunnel-type mesopore formation step Thereafter, fibrous nanocarbon is brought into contact with fibrous nanocarbon in a temperature range of 200 ° C. to 600 ° C. in a quartz glass tube having an inner diameter of 5 cm. Tunnel-type mesopores having an average pore diameter of 20 nm and an average depth of 20 nm were formed in carbon. After completion of the tunnel-type mesopore formation step, the residual carbon content, oxygen content, and BET specific surface area were measured. The residual carbon amount was calculated from the weight reduction rate, and the oxygen content was calculated from the CHN elemental analysis results.
  • Table 1 is a table showing the relationship between the air flow rate and the contact time with air during the tunnel-type mesopore formation process and the residual carbon amount, oxygen content, and BET specific surface area after the tunnel-type mesopore formation process. is there.
  • Example 1 As shown in Table 1, if the air flow rate in the tunnel mesopore formation process is increased or the contact time with the air is increased, the residual carbon amount decreases, the oxygen content increases, and the BET It can be seen that the specific surface area increases.
  • the flow rate of air is 150 sccm
  • the contact time with air is 2 hours
  • the residual carbon content is 72%
  • the oxygen content is 11.7%
  • the BET specific surface area is 222 m 2 / g.
  • the tunnel-type mesopore formation process was performed under the conditions (conditions on the fourth line from the top of Table 1).
  • Comparative Example 1 Implementing a method for producing a catalyst for a fuel cell comprising the following fibrous nanocarbon production step, iron-based transition metal catalyst particle adhesion step, tunnel-type mesopore formation step, and noble metal catalyst particle support step in this order
  • a fuel cell catalyst according to Comparative Example 1 was produced.
  • the fibrous nanocarbon production step, the iron-based transition metal catalyst particle adhesion step, and the noble metal catalyst particle supporting step are the same as in Example 1, and the tunnel-type mesopore forming step is different from that in Example 1.
  • the tunnel-type mesopore forming process is as follows.
  • Tunnel-type mesopore formation step Thereafter, a mixed gas (1: 1) of hydrogen gas / helium gas is brought into contact with fibrous nanocarbon at a temperature of 850 ° C. for 3 hours in a quartz glass tube having an inner diameter of 5 cm.
  • a mixed gas (1: 1) of hydrogen gas / helium gas is brought into contact with fibrous nanocarbon at a temperature of 850 ° C. for 3 hours in a quartz glass tube having an inner diameter of 5 cm.
  • Comparative Example 2 A fuel cell catalyst according to Comparative Example 2 was produced by carrying out a method for producing a fuel cell catalyst comprising the following fibrous nanocarbon production step and noble metal catalyst particle supporting step in this order. That is, in Comparative Example 2, noble metal catalyst particles were supported on the fibrous nanocarbon using the fibrous nanocarbon produced in the fibrous nanocarbon production step as it was. The fibrous nanocarbon production process and the noble metal catalyst particle supporting process are the same as those in Example 1.
  • Comparative Example 3 was a fuel cell catalyst sold by E-TEK in which noble metal catalyst particles were supported on carbon fine particles.
  • FIG. 6 is a diagram for explaining the single cell evaluation system 200.
  • Catalyst for fuel cell according to Example 1 and Comparative Examples 1 to 3 “Nafion 115 (manufactured by DuPont, Nafion is a trademark of DuPont Co., Ltd.) and Nafion dispersion 20% by weight” and “commercially available Pt-black (manufactured by Johnson Matthey, 6 mg / cm 2 ) ”was laminated, and an electrode assembly (MEA) 204 was produced by applying a pressure of 100 kg / cm 2 for 10 minutes at a temperature of 135 ° C. .
  • MEA electrode assembly
  • the fuel cell catalyst according to Example 1 and Comparative Examples 1 to 3 becomes the fuel electrode catalyst 212, “Nafion 115” and the Nafion dispersion become the electrolyte membrane 230, and the commercially available Pt-black becomes the air electrode catalyst 222.
  • the area of the electrode assembly 204 is 25 mm ⁇ 25 mm.
  • a fuel cell (direct methanol fuel cell) 202 is fabricated by attaching the fuel electrode current collector 214 and the air electrode current collector 224 to the electrode assembly 204, and FIG. A single cell evaluation system 200 as shown was produced.
  • FIG. 7 to 10 are diagrams showing the results of cell evaluation.
  • FIG. 7 is a diagram showing the produced power density in the unit cell using the fuel cell catalyst according to Example 1
  • FIG. 8 is the produced power density in the unit cell using the fuel cell catalyst according to Comparative Example 1.
  • FIG. 9 is a diagram showing a generated power density in a unit cell using the fuel cell catalyst according to Comparative Example 2
  • FIG. 10 is a graph using the fuel cell catalyst according to Comparative Example 3. It is a figure which shows the production electric power density in a cell.
  • Table 3 is a table showing the cell evaluation results. Table 3 shows the maximum production power density in Example 1 and Comparative Examples 1 to 3.
  • the unit cell using the fuel cell catalyst according to Example 1 is the largest compared to the unit cell using the fuel cell catalyst according to Comparative Examples 1 to 3. It was found that the produced power density is high and the fuel cell efficiency is high. *
  • fibrous nanocarbon which has a herringbone structure was used as fibrous nanocarbon
  • this invention is not limited to this.
  • fibrous nanocarbon having a platelet structure can be used.
  • the present invention is not limited to this.
  • the amount of noble metal used may be 40% by weight or more, or less than 40% by weight.
  • the fuel cell catalyst produced by the fuel cell catalyst of the present invention is used as the material for the fuel electrode catalyst, but the present invention is not limited to this.
  • it can be used as a material for an air electrode catalyst.

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Abstract

This invention provides a process for producing a catalyst for a fuel cell. The production process comprises, in the following sequence, a fibrous nanocarbon production step (S10) of thermally decomposing a carbon-containing gas in the presence of a metal catalyst or an alloy catalyst in the temperature range of 400°C to 1200°C to produce a fibrous nanocarbon, an iron-type transition metal catalyst particle deposition step (S20) of depositing iron-type transition metal catalyst particles onto the surface of the fibrous nanocarbon, a tunnel-type mesopore forming step (S30) of bringing an oxidizing gas into contact with the fibrous nanocarbonin the temperature range of 200°C to 600°C to form tunnel-type mesopores in the fibrous nanocarbon, and a noble metal catalyst particle supporting step (S40) of supporting noble metal catalyst particles in the tunnel-type mesopores. According to the above constitution, the process for producing a catalyst for a fuel cell can produce a catalyst for a fuel cell which can realize a higher fuel cell efficiency than the prior art.

Description

燃料電池用触媒の製造方法、電極接合体及び燃料電池Method for producing catalyst for fuel cell, electrode assembly and fuel cell
　本発明は、燃料電池用触媒の製造方法、電極接合体及び燃料電池に関する。 The present invention relates to a method for producing a fuel cell catalyst, an electrode assembly, and a fuel cell.
　従来、トンネル型メソ気孔を有する繊維状ナノ炭素に貴金属触媒粒子を担持させた構造を有する燃料電池用触媒が知られている（例えば、非特許文献１参照。）。 Conventionally, a fuel cell catalyst having a structure in which noble metal catalyst particles are supported on fibrous nanocarbon having tunnel-type mesopores is known (for example, see Non-Patent Document 1).
　図１１は、非特許文献１に記載された従来の燃料電池用触媒の製造方法を説明するために示すフローチャートである。図１２は、従来の燃料電池用触媒の製造方法におけるトンネル型メソ気孔形成工程Ｓ９３０を説明するために示す図である。図１２（ａ）は繊維状ナノ炭素における反応表面を示す図であり、図１２（ｂ）は炭素の結合状態の変化を示す図である。 FIG. 11 is a flowchart shown for explaining a conventional method of manufacturing a fuel cell catalyst described in Non-Patent Document 1. FIG. 12 is a view for explaining a tunnel-type mesopore forming step S930 in the conventional method for producing a fuel cell catalyst. FIG. 12A is a diagram showing a reaction surface in fibrous nanocarbon, and FIG. 12B is a diagram showing a change in the bonding state of carbon.
　従来の燃料電池用触媒の製造方法は、図１１に示すように、ヘリングボーン構造を有する繊維状ナノ炭素又はプレートレット構造を有する繊維状ナノ炭素を作製する繊維状ナノ炭素作製工程Ｓ９１０と、繊維状ナノ炭素の表面に新規触媒粒子を付着させる新規触媒粒子付着工程Ｓ９２０と、６００℃～１２００℃の温度範囲で繊維状ナノ炭素に水素ガスを接触させることにより、繊維状ナノ炭素にトンネル型メソ気孔を形成するトンネル型メソ気孔形成工程Ｓ９３０と、トンネル型メソ気孔中にＰｔＲｕ等の貴金属触媒粒子を担持させる貴金属触媒粒子担持工程Ｓ９４０とをこの順序で含むものである。 As shown in FIG. 11, the conventional method for producing a catalyst for a fuel cell includes a fibrous nanocarbon production step S910 for producing a fibrous nanocarbon having a herringbone structure or a fibrous nanocarbon having a platelet structure, A new catalyst particle attaching step S920 for attaching new catalyst particles to the surface of the fibrous nanocarbon, and contacting the fibrous nanocarbon with hydrogen gas in a temperature range of 600 ° C. to 1200 ° C. A tunnel type mesopore forming step S930 for forming pores and a noble metal catalyst particle supporting step S940 for supporting noble metal catalyst particles such as PtRu in the tunnel type mesopores are included in this order.
　そして、トンネル型メソ気孔形成工程Ｓ９３０においては、図１２に示すように、水素ガスを用いる新規の触媒ガス化法を用いることによって、繊維状ナノ炭素を構成しているナノロッドを部分的にかつ選択的に除去することで、平均孔径が３ｎｍ～１０ｎｍ程度のトンネル型メソ気孔を形成している。 Then, in the tunnel-type mesopore formation step S930, as shown in FIG. 12, the nanorod constituting the fibrous nanocarbon is selected partially and by using a novel catalytic gasification method using hydrogen gas. As a result, tunnel type mesopores having an average pore diameter of about 3 nm to 10 nm are formed.
　このため、従来の燃料電池用触媒の製造方法によれば、上記のようなトンネル型メソ気孔形成工程Ｓ９３０を含むため、繊維状ナノ炭素に、多量の、平均粒径が２ｎｍ～５ｎｍ程度の微小な貴金属触媒粒子を分散して担持させることが可能となり、結果として、高い燃料電池効率（非特許文献１の場合、産生電力密度。）を得ることが可能となる。 Therefore, according to the conventional method for producing a catalyst for a fuel cell, since the tunnel-type mesopore forming step S930 as described above is included, a large amount of fine particles having an average particle diameter of about 2 nm to 5 nm are added to the fibrous nanocarbon. As a result, it is possible to obtain high fuel cell efficiency (in the case of Non-Patent Document 1, production power density).
　ところで、燃料電池用触媒としては常に、従来よりも高い燃料電池効率を得ることが可能な燃料電池用触媒が求められている。 By the way, as a fuel cell catalyst, a fuel cell catalyst capable of obtaining higher fuel cell efficiency than ever has been demanded.
　そこで、本発明は、上記事情に鑑みてなされたもので、従来よりも高い燃料電池効率を得ることが可能な燃料電池用触媒を製造する方法を提供することを目的とする。また、そのような方法によって製造された燃料電池用触媒を用いて製造される電極接合体及び燃料電池を提供することを目的とする。 Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing a fuel cell catalyst capable of obtaining higher fuel cell efficiency than conventional ones. Moreover, it aims at providing the electrode assembly manufactured using the catalyst for fuel cells manufactured by such a method, and a fuel cell.
　本発明者らは、上述した目的を達成すべく鋭意努力を重ねた結果、酸化性ガスを用いて繊維状ナノ炭素にトンネル型メソ気孔を形成することとすれば、形成されるトンネル型メソ気孔の孔壁に多量の酸素官能基が形成されるようになるため、トンネル型メソ気孔中に従来よりも多量の貴金属触媒粒子を担持させることが可能となり、結果として、従来よりも高い燃料電池効率を得ることが可能となることを見出し、本発明を完成させるに至った。 As a result of intensive efforts to achieve the above-described object, the present inventors have formed tunnel-type mesopores in fibrous nanocarbons using an oxidizing gas. As a result, a large amount of oxygen functional groups are formed on the pore walls, so that a larger amount of noble metal catalyst particles can be supported in the tunnel-type mesopores, resulting in higher fuel cell efficiency than before. The present invention has been completed.
（１）本発明の燃料電池用触媒の製造方法は、金属触媒又は合金触媒存在下のもとで４００℃～１２００℃の温度範囲で炭素含有ガスを熱分解反応させることにより、繊維状ナノ炭素を作製する繊維状ナノ炭素作製工程と、前記繊維状ナノ炭素の表面に鉄系遷移金属触媒粒子を付着させる鉄系遷移金属触媒粒子付着工程と、２００℃～６００℃の温度範囲で前記繊維状ナノ炭素に酸化性ガスを接触させることにより、前記繊維状ナノ炭素にトンネル型メソ気孔を形成するトンネル型メソ気孔形成工程と、前記トンネル型メソ気孔中に貴金属触媒粒子を担持させる貴金属触媒粒子担持工程とをこの順序で含むことを特徴とする。 (1) The method for producing a fuel cell catalyst of the present invention comprises a fibrous nanocarbon by thermally decomposing a carbon-containing gas in the temperature range of 400 ° C. to 1200 ° C. in the presence of a metal catalyst or an alloy catalyst. A fibrous nanocarbon producing step for producing a metal, an iron-based transition metal catalyst particle adhering step for attaching iron-based transition metal catalyst particles to the surface of the fibrous nanocarbon, and the fibrous material in a temperature range of 200 ° C. to 600 ° C. A tunnel-type mesopore forming step for forming a tunnel-type mesopore in the fibrous nanocarbon by contacting an oxidizing gas with the nanocarbon, and a noble-metal catalyst particle support for supporting a noble-metal catalyst particle in the tunnel-type mesopore The steps are included in this order.
　本発明の燃料電池用触媒の製造方法によれば、繊維状ナノ炭素におけるトンネル型メソ気孔中に貴金属触媒粒子を担持させることとしているため、繊維状ナノ炭素に、多量の、平均粒径が２ｎｍ～５ｎｍ程度の微小な貴金属触媒粒子を分散して担持させることが可能となり、結果として、高い燃料電池効率を得ることが可能となる。 According to the method for producing a fuel cell catalyst of the present invention, since noble metal catalyst particles are supported in the tunnel-type mesopores in the fibrous nanocarbon, the fibrous nanocarbon has a large average particle diameter of 2 nm. It becomes possible to disperse and carry fine noble metal catalyst particles of about ˜5 nm, and as a result, high fuel cell efficiency can be obtained.
　また、本発明の燃料電池用触媒の製造方法によれば、トンネル型メソ気孔形成工程において酸化性ガスを用いて繊維状ナノ炭素にトンネル型メソ気孔を形成することとしているため、形成されるトンネル型メソ気孔の孔壁に多量の酸素官能基が形成されるようになる。このため、繊維状ナノ炭素に従来よりも多量の貴金属触媒粒子を担持させることが可能となる。 In addition, according to the method for producing a fuel cell catalyst of the present invention, tunnel mesopores are formed in the fibrous nanocarbon using an oxidizing gas in the tunnel-type mesopore forming step. A large amount of oxygen functional groups are formed on the pore walls of the type mesopores. For this reason, it becomes possible to carry | support the noble metal catalyst particle of a larger amount than before on fibrous nanocarbon.
　その結果、本発明の燃料電池用触媒の製造方法によれば、従来よりも高い燃料電池効率を得ることが可能な燃料電池用触媒を製造することできる。 As a result, according to the method for producing a fuel cell catalyst of the present invention, a fuel cell catalyst capable of obtaining higher fuel cell efficiency than before can be produced.
　また、本発明の燃料電池用触媒の製造方法によれば、従来よりも低い温度で繊維状ナノ炭素にトンネル型メソ気孔を形成することが可能となるため、従来よりも安価な製造コストで燃料電池用触媒を製造することができる。 Further, according to the method for producing a catalyst for a fuel cell of the present invention, it becomes possible to form tunnel-type mesopores in fibrous nanocarbon at a temperature lower than that in the past, so that fuel can be produced at a lower production cost than in the past. A battery catalyst can be produced.
（２）本発明の燃料電池用触媒の製造方法においては、前記繊維状ナノ炭素作製工程で作製する繊維状ナノ炭素は、ヘリングボーン構造を有する繊維状ナノ炭素又はプレートレット構造を有する繊維状ナノ炭素であることが好ましい。 (2) In the method for producing a fuel cell catalyst of the present invention, the fibrous nanocarbon produced in the fibrous nanocarbon production step is a fibrous nanocarbon having a herringbone structure or a fibrous nanocarbon having a platelet structure. Carbon is preferred.
　ヘリングボーン構造を有する繊維状ナノ炭素又はプレートレット構造を有する繊維状ナノ炭素は、これらの繊維状ナノ炭素を構成するナノロッドの軸幅Ｄ（後述する図２（ｃ）参照。）が例えば２．５ｎｍ程度である。従って、上記のような方法とすることにより、繊維状ナノ炭素に、多量の、平均粒径が２ｎｍ～５ｎｍ程度の微小な貴金属触媒粒子を分散して担持可能なトンネル型メソ気孔を形成することが可能となる。 The fibrous nanocarbon having a herringbone structure or the fibrous nanocarbon having a platelet structure has an axial width D (see FIG. 2C described later) of nanorods constituting these fibrous nanocarbons, for example, 2. It is about 5 nm. Therefore, by using the above-described method, a tunnel-type mesopore capable of supporting a large amount of fine noble metal catalyst particles having an average particle diameter of about 2 nm to 5 nm dispersed in fibrous nanocarbon can be formed. Is possible.
（３）本発明の燃料電池用触媒の製造方法においては、前記貴金属触媒粒子は、平均粒径が２ｎｍ～５ｎｍの範囲内にあり、前記トンネル型メソ気孔は、平均孔径が２．５ｎｍ～１００ｎｍの範囲内にあり、平均深さが１０ｎｍ以上の範囲内にあることが好ましい。 (3) In the method for producing a fuel cell catalyst according to the present invention, the noble metal catalyst particles have an average particle diameter in the range of 2 nm to 5 nm, and the tunnel-type mesopores have an average pore diameter of 2.5 nm to 100 nm. It is preferable that the average depth is in the range of 10 nm or more.
　このような方法とすることにより、トンネル型メソ気孔中に、平均粒径が２ｎｍ～５ｎｍ程度の微小な貴金属触媒粒子を確実に担持させることができる。 By adopting such a method, fine noble metal catalyst particles having an average particle diameter of about 2 nm to 5 nm can be reliably supported in the tunnel type mesopores.
（４）本発明の燃料電池用触媒の製造方法においては、前記鉄系遷移金属触媒粒子は、平均粒径が２．５ｎｍ～１００ｎｍの範囲内にあることが好ましい。 (4) In the method for producing a fuel cell catalyst of the present invention, the iron-based transition metal catalyst particles preferably have an average particle size in the range of 2.5 nm to 100 nm.
　このような方法とすることにより、平均孔径が２．５ｎｍ～１００ｎｍの範囲内にあるトンネル型メソ気孔、言い換えれば、平均粒径が２～５ｎｍ程度の微小な貴金属触媒粒子を多量担持させることが可能なトンネル型メソ気孔を形成することができる。 By adopting such a method, it is possible to carry a large amount of tunnel-type mesopores having an average pore diameter in the range of 2.5 nm to 100 nm, in other words, fine noble metal catalyst particles having an average particle diameter of about 2 to 5 nm. Possible tunnel-type mesopores can be formed.
（５）本発明の燃料電池用触媒の製造方法においては、前記繊維状ナノ炭素作製工程で作製する繊維状ナノ炭素は、ＢＥＴ比表面積が２００ｍ２／ｇ以上であることが好ましい。 (5) In the manufacturing method of the catalyst for fuel cells of this invention, it is preferable that the fibrous nanocarbon produced at the said fibrous nanocarbon preparation process has a BET specific surface area of 200 m < 2 > / g or more.
　このような方法とすることにより、繊維状ナノ炭素に多量の貴金属触媒粒子を担持させることが可能となる。 By using such a method, a large amount of noble metal catalyst particles can be supported on the fibrous nanocarbon.
（６）本発明の燃料電池用触媒の製造方法においては、前記酸化性ガスは、空気、不活性ガスと酸素ガスとの混合ガス又は純酸素ガスであることが好ましい。 (6) In the method for producing a fuel cell catalyst of the present invention, the oxidizing gas is preferably air, a mixed gas of inert gas and oxygen gas, or pure oxygen gas.
　このような方法とすることにより、トンネル型メソ気孔中に多量の酸素官能基を導入することが可能となる。 By adopting such a method, a large amount of oxygen functional groups can be introduced into the tunnel type mesopores.
（７）本発明の燃料電池用触媒の製造方法においては、前記トンネル型メソ気孔形成工程終了後の繊維状ナノ炭素には、０．５重量％～２０重量％の酸素が含まれていることが好ましい。 (7) In the method for producing a fuel cell catalyst of the present invention, the fibrous nanocarbon after the completion of the tunnel-type mesopore formation step contains 0.5 wt% to 20 wt% oxygen. Is preferred.
　このような方法とすることにより、トンネル型メソ気孔中には多量の酸素官能基が導入されていることとなり、その結果、トンネル型メソ気孔中に貴金属触媒粒子を安定して担持させることが可能となる。 By adopting such a method, a large amount of oxygen functional groups are introduced into the tunnel type mesopores, and as a result, the noble metal catalyst particles can be stably supported in the tunnel type mesopores. It becomes.
（８）本発明の燃料電池用触媒の製造方法においては、前記鉄系遷移金属触媒粒子は、Ｆｅ、Ｎｉ若しくはＣｏ又はこれらの合金の微粒子からなることが好ましい。 (8) In the method for producing a fuel cell catalyst of the present invention, the iron-based transition metal catalyst particles are preferably composed of fine particles of Fe, Ni, Co, or an alloy thereof.
　このような方法とすることにより、酸化性ガスを用いて繊維状ナノ炭素に上記したようなトンネル型メソ気孔を形成することが可能となる。 By adopting such a method, it becomes possible to form tunnel-type mesopores as described above in fibrous nanocarbon using an oxidizing gas.
（９）本発明の燃料電池用触媒の製造方法においては、前記貴金属触媒粒子は、Ｐｔ、Ｒｕ若しくはＰｄ又はこれらの貴金属を含む合金の微粒子からなることが好ましい。 (9) In the method for producing a fuel cell catalyst of the present invention, the noble metal catalyst particles are preferably composed of fine particles of Pt, Ru or Pd or an alloy containing these noble metals.
　このような方法とすることにより、高い燃料電池効率を得ることが可能な燃料電池用触媒を製造することができる。 By using such a method, a fuel cell catalyst capable of obtaining high fuel cell efficiency can be produced.
（１０）本発明の電極接合体は、本発明の燃料電池用触媒の製造方法によって製造される燃料電池用触媒に炭素含有ペーストを混合して得られるスラリーから製造される燃料電池用触媒であって、前記スラリーにおける貴金属触媒粒子の全重量と炭素の全重量との和に占める前記貴金属触媒粒子の全重量の比率（貴金属使用量）は、４０％以下であることを特徴とする。 (10) The electrode assembly of the present invention is a fuel cell catalyst produced from a slurry obtained by mixing a carbon-containing paste with a fuel cell catalyst produced by the method for producing a fuel cell catalyst of the invention. The ratio of the total weight of the noble metal catalyst particles to the sum of the total weight of the noble metal catalyst particles and the total weight of carbon in the slurry (precious metal usage amount) is 40% or less.
　本発明の電極接合体は、本発明の燃料電池用触媒の製造方法によって製造される燃料電池用触媒に炭素含有ペーストを混合して得られるスラリーから製造される電極接合体であるため、従来よりも高い燃料電池効率を得ることが可能な電極接合体となる。また、本発明の電極接合体は、貴金属使用量を８０％程度以上とすることも可能であるが、貴金属使用量を４０％以下とすることにより、貴金属触媒粒子の使用量が少なく製造コストの比較的安価な電極接合体となる。 Since the electrode assembly of the present invention is an electrode assembly manufactured from a slurry obtained by mixing a carbon-containing paste with a fuel cell catalyst manufactured by the method for manufacturing a fuel cell catalyst of the present invention, In other words, the electrode assembly can obtain high fuel cell efficiency. In addition, the electrode assembly of the present invention can make the amount of precious metal used about 80% or more, but by making the amount of precious metal used 40% or less, the amount of precious metal catalyst particles used is small and the production cost is low. It becomes a relatively inexpensive electrode assembly.
（１１）本発明の燃料電池は、９０℃運転時に１６０ｍＷ／ｃｍ２以上の電力を産生可能であることを特徴とする。 (11) The fuel cell of the present invention is characterized in that it can produce electric power of 160 mW / cm 2 or more during operation at 90 ° C.
　本発明の燃料電池は、上記した電極接合体を備える燃料電池であるため、後述する実施例からも明らかなように、貴金属触媒粒子の使用量が少なく製造コストの比較的安価な燃料電池でありながら、所定の燃料電池効率を得ることが可能な燃料電池となる。 Since the fuel cell of the present invention is a fuel cell including the above-described electrode assembly, as is clear from the examples described later, the amount of noble metal catalyst particles used is small and the manufacturing cost is relatively low. However, the fuel cell can achieve a predetermined fuel cell efficiency.
（１２）本発明の燃料電池は、９０℃運転時に１８５ｍＷ／ｃｍ２以上の電力を産生可能であることを特徴とする。 (12) The fuel cell of the present invention is characterized in that it can produce electric power of 185 mW / cm 2 or more during operation at 90 ° C.
　本発明の燃料電池は、上記した電極接合体を備える燃料電池であるため、後述する実施例からも明らかなように、貴金属触媒粒子の使用量が少なく製造コストの比較的安価な燃料電池でありながら、所定の燃料電池効率を得ることが可能な燃料電池となる。 Since the fuel cell of the present invention is a fuel cell including the above-described electrode assembly, as is clear from the examples described later, the amount of noble metal catalyst particles used is small and the manufacturing cost is relatively low. However, the fuel cell can achieve a predetermined fuel cell efficiency.
実施形態に係る燃料電池用触媒の製造方法を説明するために示すフローチャートである。It is a flowchart shown in order to demonstrate the manufacturing method of the catalyst for fuel cells which concerns on embodiment. 繊維状ナノ炭素１００の構造を説明するために示す図である。It is a figure shown in order to demonstrate the structure of fibrous nanocarbon 100. FIG. 実施形態に係る燃料電池用触媒の製造方法を説明するために示す図である。It is a figure shown in order to demonstrate the manufacturing method of the catalyst for fuel cells which concerns on embodiment. 実施形態に係る燃料電池用触媒の製造方法を説明するために示す図である。It is a figure shown in order to demonstrate the manufacturing method of the catalyst for fuel cells which concerns on embodiment. 実施形態に係る燃料電池用触媒１００ｂを説明するために示す図である。It is a figure shown in order to demonstrate the catalyst 100b for fuel cells which concerns on embodiment. 単電池評価系２００を説明するために示す図である。It is a figure shown in order to demonstrate the cell evaluation system 200. FIG. 比較例１に係る燃料電池用触媒が産生する電力密度を示す図である。It is a figure which shows the power density which the catalyst for fuel cells which concerns on the comparative example 1 produces. 比較例２に係る燃料電池用触媒が産生する電力密度を示す図である。It is a figure which shows the power density which the catalyst for fuel cells which concerns on the comparative example 2 produces. 比較例３に係る燃料電池用触媒が産生する電力密度を示す図である。It is a figure which shows the power density which the catalyst for fuel cells which concerns on the comparative example 3 produces. 実施例１に係る燃料電池用触媒が産生する電力密度を示す図である。It is a figure which shows the power density which the catalyst for fuel cells which concerns on Example 1 produces. 非特許文献１に記載された燃料電池用触媒の製造方法を説明するために示すフローチャートである。3 is a flowchart shown for explaining a method for producing a fuel cell catalyst described in Non-Patent Document 1. 非特許文献１に記載された燃料電池用触媒の製造方法におけるトンネル型メソ気孔形成工程を説明するために示す図である。It is a figure shown in order to demonstrate the tunnel type meso pore formation process in the manufacturing method of the catalyst for fuel cells described in the nonpatent literature 1.
　以下、本発明の燃料電池用触媒の製造方法、電極接合体及び燃料電池について、図に示す実施の形態に基づいて説明する。 Hereinafter, a method for producing a catalyst for a fuel cell, an electrode assembly, and a fuel cell of the present invention will be described based on the embodiments shown in the drawings.
［実施形態］
　図１は、実施形態に係る燃料電池用触媒の製造方法を示すフローチャートである。
　図２は、繊維状ナノ炭素作製工程Ｓ１０終了後における繊維状ナノ炭素１００の構造を説明するために示す図である。図２（ａ）は１本の繊維状ナノ炭素１００を模式的に示す図であり、図２（ｂ）は図２（ａ）における符号Ａ１で示す部分の拡大図であり、図２（ｃ）はナノロッド１０６の拡大図である。 [Embodiment]
FIG. 1 is a flowchart showing a method for manufacturing a fuel cell catalyst according to an embodiment.
FIG. 2 is a diagram shown for explaining the structure of the fibrous nanocarbon 100 after completion of the fibrous nanocarbon production step S10. 2 (a) is a diagram showing one fibrous nanocarbon 100 schematically, and FIG. 2 (b) is an enlarged view of a portion indicated by reference sign A 1 in FIG. 2 (a), 2 ( c) is an enlarged view of the nanorod 106. FIG.
　図３及び図４は、実施形態に係る燃料電池用触媒の製造方法を説明するために示す図である。図３（ａ）は繊維状ナノ炭素作製工程Ｓ１０終了後における繊維状ナノ炭素１００の構造を示す図であり、図３（ｂ）は鉄系遷移金属触媒粒子付着工程Ｓ２０終了後における繊維状ナノ炭素１００の構造を示す図であり、図３（ｃ）及び図３（ｄ）並びに図４（ａ）はトンネル型メソ気孔形成工程Ｓ３０実施中における繊維状ナノ炭素１００の構造を示す図であり、図４（ｂ）はトンネル型メソ気孔形成工程Ｓ３０終了後に鉄系遷移金属触媒粒子１１０を除去した後における繊維状ナノ炭素１００の構造を示す図であり、図４（ｃ）は貴金属触媒粒子担持工程Ｓ４０終了後における繊維状ナノ炭素１００の構造を示す図である。 FIG. 3 and FIG. 4 are diagrams for explaining a method of manufacturing a fuel cell catalyst according to the embodiment. FIG. 3A is a diagram showing the structure of the fibrous nanocarbon 100 after the completion of the fibrous nanocarbon production step S10, and FIG. 3B is the fibrous nanocarbon after the completion of the iron-based transition metal catalyst particle attaching step S20. FIG. 3 (c), FIG. 3 (d), and FIG. 4 (a) are diagrams showing the structure of fibrous nanocarbon 100 during tunnel-type mesopore formation step S30. 4 (b) is a diagram showing the structure of the fibrous nanocarbon 100 after the iron-based transition metal catalyst particles 110 are removed after the tunnel-type mesopore forming step S30 is completed, and FIG. 4 (c) is the noble metal catalyst particles. It is a figure which shows the structure of fibrous nanocarbon 100 after completion | finish of carrying | support process S40.
　図５は、実施形態に係る燃料電池用触媒１００ｂを説明するために示す図である。図５（ａ）は燃料電池用触媒１００ｂの透過型電子顕微鏡による写真であり、図５（ｂ）は図５（ａ）をさらに拡大した写真である。 FIG. 5 is a view for explaining the fuel cell catalyst 100b according to the embodiment. FIG. 5A is a transmission electron microscope photograph of the fuel cell catalyst 100b, and FIG. 5B is an enlarged photograph of FIG. 5A.
　実施形態に係る燃料電池用触媒の製造方法は、図１に示すように、繊維状ナノ炭素作製工程Ｓ１０と、鉄系遷移金属触媒粒子付着工程Ｓ２０と、トンネル型メソ気孔形成工程Ｓ３０と、貴金属触媒粒子担持工程Ｓ４０とをこの順序で含む。以下、各工程を詳細に説明する。 As shown in FIG. 1, the method for producing a fuel cell catalyst according to the embodiment includes a fibrous nanocarbon production step S10, an iron-based transition metal catalyst particle adhesion step S20, a tunnel-type mesopore formation step S30, and a noble metal. The catalyst particle supporting step S40 is included in this order. Hereinafter, each process will be described in detail.
１．繊維状ナノ炭素作製工程Ｓ１０
　繊維状ナノ炭素作製工程Ｓ１０は、金属触媒又は合金触媒存在下のもとで４００℃～１２００℃の温度範囲で炭素含有ガスを熱分解反応させることにより、繊維状ナノ炭素１００を作製する工程である（図３（ａ）参照。）。 1. Fibrous nanocarbon production process S10
Fibrous nanocarbon production step S10 is a step of producing fibrous nanocarbon 100 by subjecting a carbon-containing gas to a thermal decomposition reaction in the temperature range of 400 ° C. to 1200 ° C. in the presence of a metal catalyst or an alloy catalyst. Yes (see FIG. 3A).
　金属触媒又は合金触媒としては、鉄、ニッケル、コバルトなどの遷移金属又はこれらの合金から製造される触媒（例えば、硝酸鉄、硝酸ニッケルなど。）を用いる。炭素含有ガスとしては、一酸化炭素（ＣＯ）又は炭化水素（例えば、メタン（ＣＨ３）、エチレン（Ｃ２Ｈ４）、プロパン（Ｃ３Ｈ８）など。）を用いる。キャリアガスとして水素（水素分圧０％～９０％）を用いてもよい。熱分解反応は、４００℃～１２００℃の温度範囲で、上記した炭素含有ガスを上記した金属触媒又は合金触媒に接触させることにより行う。 As the metal catalyst or alloy catalyst, a transition metal such as iron, nickel, cobalt, or a catalyst produced from an alloy thereof (for example, iron nitrate, nickel nitrate, etc.) is used. As the carbon-containing gas, carbon monoxide (CO) or hydrocarbon (for example, methane (CH 3 ), ethylene (C 2 H 4 ), propane (C 3 H 8 ), etc.) is used. Hydrogen (hydrogen partial pressure of 0% to 90%) may be used as the carrier gas. The thermal decomposition reaction is performed by bringing the above-mentioned carbon-containing gas into contact with the above-described metal catalyst or alloy catalyst in a temperature range of 400 ° C. to 1200 ° C.
　繊維状ナノ炭素作製工程Ｓ１０で作製される繊維状ナノ炭素１００は、例えば、図２に示すように、ナノロッド群の配列角度がナノロッドの積層方向の繊維軸と直交する軸に対して２０度より大きく８０度未満の角度で配列したヘリングボーン構造を有する繊維状ナノ炭素である。ナノロッド群は、多数のナノロッド１０６が互いに平行に配列された構造を有する。ナノロッド１０６は、六角柱の形状を有し、かつ、炭素六角網面が同心状に積層された構造を有する。なお、図２（ｂ）中、符号１０２は金属触媒又は合金触媒を示し、符号１０４は多数のナノロッド１０６が互いに平行に配列された構造を示す。金属触媒又は合金触媒１０２の短径Ｗａは、例えば５０～１５０ｎｍであり、金属触媒又は合金触媒１０２の長径Ｗｂは、例えば５０ｎｍ～３００ｎｍである。また、図２（ｃ）に示すナノロッド１０６の軸幅Ｄは、例えば２．５ｎｍであり、ナノロッド１０６の長さＬは、例えば２０ｎｍである。また、繊維状ナノ炭素１００の長さは、例えば５００ｎｍ～３０００ｎｍである。 In the fibrous nanocarbon 100 produced in the fibrous nanocarbon production step S10, for example, as shown in FIG. 2, the arrangement angle of the nanorod group is more than 20 degrees with respect to the axis perpendicular to the fiber axis in the nanorod stacking direction. It is a fibrous nanocarbon having a herringbone structure arranged at an angle of largely less than 80 degrees. The nanorod group has a structure in which a large number of nanorods 106 are arranged in parallel to each other. The nanorod 106 has a hexagonal column shape and a structure in which carbon hexagonal mesh surfaces are stacked concentrically. In FIG. 2B, reference numeral 102 indicates a metal catalyst or alloy catalyst, and reference numeral 104 indicates a structure in which a number of nanorods 106 are arranged in parallel to each other. The short diameter Wa of the metal catalyst or alloy catalyst 102 is, for example, 50 to 150 nm, and the long diameter Wb of the metal catalyst or alloy catalyst 102 is, for example, 50 nm to 300 nm. Moreover, the axial width D of the nanorod 106 illustrated in FIG. 2C is, for example, 2.5 nm, and the length L of the nanorod 106 is, for example, 20 nm. The length of the fibrous nanocarbon 100 is, for example, 500 nm to 3000 nm.
２．鉄系遷移金属触媒粒子付着工程Ｓ２０
　鉄系遷移金属触媒粒子付着工程Ｓ２０は、繊維状ナノ炭素１００の表面に鉄系遷移金属触媒粒子１１０を付着させる工程である（図３（ｂ）参照。）。 2. Iron-based transition metal catalyst particle adhesion step S20
The iron-based transition metal catalyst particle attaching step S20 is a step of attaching the iron-based transition metal catalyst particles 110 to the surface of the fibrous nanocarbon 100 (see FIG. 3B).
　鉄系遷移金属触媒粒子付着工程Ｓ２０は、鉄系遷移金属触媒粒子１１０を含有させた溶液に、繊維状ナノ炭素１００を浸漬した後、繊維状ナノ炭素１００を乾燥させることにより行う。鉄系遷移金属触媒粒子１１０としては、Ｆｅ、Ｎｉ若しくはＣｏ又はこれらの合金の微粒子からなるものを用いる。また、鉄系遷移金属触媒粒子１１０としては、平均粒径が２．５ｎｍ～１００ｎｍの範囲内にあるものを用いる。 The iron-based transition metal catalyst particle adhering step S20 is performed by immersing the fibrous nanocarbon 100 in a solution containing the iron-based transition metal catalyst particles 110, and then drying the fibrous nanocarbon 100. As the iron-based transition metal catalyst particles 110, those composed of fine particles of Fe, Ni, Co, or alloys thereof are used. Further, as the iron-based transition metal catalyst particles 110, those having an average particle diameter in the range of 2.5 nm to 100 nm are used.
３．トンネル型メソ気孔形成工程Ｓ３０
　トンネル型メソ気孔形成工程Ｓ３０は、２００℃～６００℃の温度範囲で繊維状ナノ炭素１００に酸化性ガスを接触させることにより、繊維状ナノ炭素１００にトンネル型メソ気孔１２０を形成する工程である（図３（ｃ）及び図３（ｄ）並びに図４（ａ）参照。）。 3. Tunnel type mesopore forming step S30
The tunnel-type mesopore forming step S30 is a step of forming the tunnel-type mesopores 120 in the fibrous nanocarbon 100 by contacting the fibrous nanocarbon 100 with an oxidizing gas in a temperature range of 200 ° C. to 600 ° C. (See FIG. 3C, FIG. 3D, and FIG. 4A.)
　酸化性ガスとしては、例えば、空気、不活性ガスと酸素ガスとの混合ガス又は純酸素ガスを用いる。
　トンネル型メソ気孔形成工程Ｓ３０においては、接触時間が経過するに従ってトンネル型メソ気孔が徐々に成長するため、平均孔径が２．５ｎｍ～１００ｎｍの範囲内にあり、ナノロッド１０６の軸方向Ｂ（図４（ｂ）及び図２（ｂ）参照。）に沿った平均長さ（平均深さ）が１０ｎｍ以上のトンネル型メソ気孔を制御性よく形成することができる。 As the oxidizing gas, for example, air, a mixed gas of inert gas and oxygen gas, or pure oxygen gas is used.
In the tunnel-type mesopore formation step S30, the tunnel-type mesopores grow gradually as the contact time elapses, so that the average pore diameter is in the range of 2.5 nm to 100 nm, and the axial direction B of the nanorod 106 (FIG. 4). Tunnel type mesopores having an average length (average depth) of 10 nm or more along (b) and FIG. 2B) can be formed with good controllability.
４．貴金属触媒粒子担持工程Ｓ４０
　貴金属触媒粒子担持工程Ｓ４０は、トンネル型メソ気孔１２０中に貴金属触媒粒子１３０を担持させる工程である（図４（ｂ）～図４（ｄ）参照。）。 4). Precious metal catalyst particle supporting step S40
The noble metal catalyst particle supporting step S40 is a step of supporting the noble metal catalyst particles 130 in the tunnel-type mesopores 120 (see FIGS. 4B to 4D).
　貴金属触媒粒子担持工程Ｓ４０は、繊維状ナノ炭素１００から鉄系遷移金属触媒粒子１１０を除去した後、貴金属触媒粒子１３０を含有する溶液に、繊維状ナノ炭素１００を浸漬することにより行う。貴金属触媒粒子１３０としては、Ｐｔ、Ｒｕ若しくはＰｄ又はこれらの貴金属を含む合金の微粒子からなるものを用いる。また、貴金属触媒粒子１３０としては、平均粒径が２ｎｍ～５ｎｍの範囲内にあるものを用いる。貴金属触媒粒子担持工程Ｓ４０終了後には、多数の貴金属触媒粒子１３０がトンネル型メソ気孔１２０中に担持された構造の燃料電池用触媒１４０が得られる（図４（ｃ）及び図４（ｄ）並びに図５（ａ）及び図５（ｂ）参照。）。 The noble metal catalyst particle supporting step S40 is performed by removing the iron-based transition metal catalyst particles 110 from the fibrous nanocarbon 100 and then immersing the fibrous nanocarbon 100 in a solution containing the noble metal catalyst particles 130. As the noble metal catalyst particles 130, those made of fine particles of Pt, Ru, Pd, or an alloy containing these noble metals are used. Further, as the noble metal catalyst particles 130, those having an average particle diameter in the range of 2 nm to 5 nm are used. After completion of the noble metal catalyst particle supporting step S40, a fuel cell catalyst 140 having a structure in which a large number of noble metal catalyst particles 130 are supported in the tunnel type mesopores 120 is obtained (FIGS. 4C and 4D) and FIG. (See FIG. 5A and FIG. 5B.)
　以上のようにして実施形態に係る燃料電池用触媒１４０を製造することができる。 The fuel cell catalyst 140 according to the embodiment can be manufactured as described above.
　なお、図示による説明は省略するが、本発明においては、このようにして製造される燃料電池用触媒１４０に炭素含有ペーストを混合して得られるスラリーを用いて電極接合体を製造することができ、また、このようにして製造される電極接合体を用いて燃料電池を製造することができる。 In addition, although description by illustration is abbreviate | omitted, in this invention, an electrode assembly can be manufactured using the slurry obtained by mixing a carbon containing paste with the catalyst 140 for fuel cells manufactured in this way. Moreover, a fuel cell can be manufactured using the electrode assembly manufactured in this way.
　以上、実施形態に係る燃料電池用触媒の製造方法、電極接合体及び燃料電池を説明したが、実施形態に係る燃料電池用触媒の製造方法によれば、繊維状ナノ炭素１００におけるトンネル型メソ気孔１２０中に貴金属触媒粒子１３０を担持させることとしているため、繊維状ナノ炭素１００に、多量の、平均粒径が２ｎｍ～５ｎｍ程度の微小な貴金属触媒粒子１３０を分散して担持させることが可能となり、結果として、高い燃料電池効率を得ることが可能となる。 Although the fuel cell catalyst manufacturing method, electrode assembly, and fuel cell according to the embodiment have been described above, according to the fuel cell catalyst manufacturing method according to the embodiment, the tunnel-type mesopores in the fibrous nanocarbon 100 Since noble metal catalyst particles 130 are supported in 120, a large amount of fine noble metal catalyst particles 130 having an average particle diameter of about 2 nm to 5 nm can be dispersed and supported on the fibrous nanocarbon 100. As a result, high fuel cell efficiency can be obtained.
　また、実施形態に係る燃料電池用触媒の製造方法によれば、トンネル型メソ気孔形成工程Ｓ３０において酸化性ガスを用いて繊維状ナノ炭素１００にトンネル型メソ気孔１２０を形成することとしているため、形成されるトンネル型メソ気孔１２０の孔壁には多量の酸素官能基が形成される。このため、繊維状ナノ炭素１００に従来よりも多量の貴金属触媒１３０を担持させることが可能となる。 Further, according to the method for manufacturing a fuel cell catalyst according to the embodiment, the tunnel-type mesopores 120 are formed in the fibrous nanocarbon 100 using the oxidizing gas in the tunnel-type mesopore formation step S30. A large amount of oxygen functional groups are formed on the pore walls of the tunnel-type mesopores 120 to be formed. For this reason, it becomes possible to make the fibrous nanocarbon 100 carry a larger amount of the noble metal catalyst 130 than before.
　その結果、実施形態に係る燃料電池用触媒の製造方法によれば、従来よりも高い燃料電池効率を得ることが可能な燃料電池用触媒を製造することできる。 As a result, according to the method for producing a fuel cell catalyst according to the embodiment, it is possible to produce a fuel cell catalyst capable of obtaining higher fuel cell efficiency than before.
　また、実施形態に係る燃料電池用触媒の製造方法によれば、従来よりも低い温度で繊維状ナノ炭素１００にトンネル型メソ気孔１２０を形成することが可能となるため、従来よりも安価な製造コストで燃料電池用触媒を製造することができる。 In addition, according to the method for manufacturing a fuel cell catalyst according to the embodiment, it is possible to form the tunnel mesopores 120 in the fibrous nanocarbon 100 at a temperature lower than that of the conventional method, and therefore, the manufacturing cost is lower than that of the conventional method. A fuel cell catalyst can be produced at low cost.
　また、実施形態に係る燃料電池用触媒の製造方法によれば、繊維状ナノ炭素作製工程Ｓ１０で作製する繊維状ナノ炭素１００がヘリングボーン構造を有する繊維状ナノ炭素であるため、繊維状ナノ炭素１００に、多量の、平均粒径が２ｎｍ～５ｎｍ程度の微小な貴金属触媒粒子を分散して担持可能なトンネル型メソ気孔１２０を形成することが可能となる。 In addition, according to the method for manufacturing a fuel cell catalyst according to the embodiment, since the fibrous nanocarbon 100 produced in the fibrous nanocarbon production step S10 is a fibrous nanocarbon having a herringbone structure, the fibrous nanocarbon. It is possible to form a tunnel-type mesopore 120 capable of dispersing and supporting a large amount of fine noble metal catalyst particles having an average particle diameter of about 2 nm to 5 nm.
　また、実施形態に係る燃料電池用触媒の製造方法によれば、貴金属触媒粒子１３０は、平均粒径が２ｎｍ～５ｎｍの範囲内にあり、トンネル型メソ気孔１２０は、平均孔径が２．５ｎｍ～１００ｎｍの範囲内にありかつ平均深さが１０ｎｍ以上の範囲内にあるため、トンネル型メソ気孔１２０中に、平均粒径が２ｎｍ～５ｎｍ程度の微小な貴金属触媒粒子１３０を担持させることができる。 Further, according to the method for manufacturing a fuel cell catalyst according to the embodiment, the noble metal catalyst particles 130 have an average particle diameter in the range of 2 nm to 5 nm, and the tunnel-type mesopores 120 have an average pore diameter of 2.5 nm to Since it is in the range of 100 nm and the average depth is in the range of 10 nm or more, minute noble metal catalyst particles 130 having an average particle diameter of about 2 nm to 5 nm can be supported in the tunnel type mesopores 120.
　また、実施形態に係る燃料電池用触媒の製造方法によれば、鉄系遷移金属触媒粒子１１０は、平均粒径が２．５ｎｍ～１００ｎｍの範囲内にあるため、平均孔径が２．５ｎｍ～１００ｎｍの範囲内にあるトンネル型メソ気孔１２０、言い換えれば、平均粒径が２ｎｍ～５ｎｍ程度の微小な貴金属触媒粒子１３０を多量担持させることが可能なトンネル型メソ気孔を形成することができる。 In addition, according to the method for manufacturing a fuel cell catalyst according to the embodiment, since the iron-based transition metal catalyst particles 110 have an average particle diameter in the range of 2.5 nm to 100 nm, the average pore diameter is 2.5 nm to 100 nm. In other words, the tunnel-type mesopores 120 within the range, that is, the tunnel-type mesopores capable of supporting a large amount of fine noble metal catalyst particles 130 having an average particle diameter of about 2 nm to 5 nm can be formed.
　また、実施形態に係る燃料電池用触媒の製造方法によれば、繊維状ナノ炭素作製工程Ｓ１０で作製する繊維状ナノ炭素１００は、ＢＥＴ比表面積が２００ｍ２／ｇ以上であるため、繊維状ナノ炭素１００に多量の貴金属触媒粒子１３０を担持させることが可能となる。 In addition, according to the method for producing a fuel cell catalyst according to the embodiment, the fibrous nanocarbon 100 produced in the fibrous nanocarbon production step S10 has a BET specific surface area of 200 m 2 / g or more. A large amount of noble metal catalyst particles 130 can be supported on the carbon 100.
　また、実施形態に係る燃料電池用触媒の製造方法によれば、酸化性ガスは、空気、不活性ガスと酸素ガスとの混合ガス又は純酸素ガスであるため、トンネル型メソ気孔１２０中に多量の酸素官能基を導入することが可能となる。 In addition, according to the method for manufacturing a fuel cell catalyst according to the embodiment, the oxidizing gas is air, a mixed gas of inert gas and oxygen gas, or pure oxygen gas, so It is possible to introduce the oxygen functional group.
　また、実施形態に係る燃料電池用触媒の製造方法によれば、トンネル型メソ気孔形成工程Ｓ３０終了後の繊維状ナノ炭素１００には、０．５重量％～２０重量％の酸素が含まれているため、トンネル型メソ気孔１２０中に貴金属触媒粒子１３０を安定して担持させることが可能となる。 Further, according to the method for manufacturing a fuel cell catalyst according to the embodiment, the fibrous nanocarbon 100 after the completion of the tunnel-type mesopore forming step S30 contains 0.5 wt% to 20 wt% of oxygen. Therefore, the noble metal catalyst particles 130 can be stably supported in the tunnel type mesopores 120.
　また、実施形態に係る燃料電池用触媒の製造方法によれば、鉄系遷移金属触媒粒子１１０は、Ｆｅ、Ｎｉ若しくはＣｏ又はこれらの合金の微粒子からなるため、酸化性ガスを用いて繊維状ナノ炭素に上記したようなトンネル型メソ気孔１２０を形成することが可能となる。 In addition, according to the method for manufacturing a fuel cell catalyst according to the embodiment, the iron-based transition metal catalyst particles 110 are made of fine particles of Fe, Ni, Co, or an alloy thereof. It is possible to form the tunnel-type mesopores 120 as described above in carbon.
　以下、実施例を参照しながら、本発明の燃料電池用触媒の製造方法、電極接合体及び燃料電池の効果を説明する。 Hereinafter, the effects of the method for producing a fuel cell catalyst, the electrode assembly, and the fuel cell of the present invention will be described with reference to examples.
　１．試料の作製
［実施例１］
　以下の繊維状ナノ炭素作製工程と、鉄系遷移金属触媒粒子付着工程と、トンネル型メソ気孔形成工程と、貴金属触媒粒子担持工程とをこの順序で含む燃料電池用触媒の製造方法を実施することにより、実施例１に係る燃料電池用触媒を作製した。 1. Sample Preparation [Example 1]
Implementing a method for producing a catalyst for a fuel cell comprising the following fibrous nanocarbon production step, iron-based transition metal catalyst particle adhesion step, tunnel-type mesopore formation step, and noble metal catalyst particle support step in this order Thus, a fuel cell catalyst according to Example 1 was produced.
（１）繊維状ナノ炭素作製工程
　沈澱法を用いて調整した超微粒子状のニッケル触媒５０ｍｇを石英ガラス製のボート（長さ１０ｍｍ、幅２．５ｍｍ、深さ１．５ｍｍ）に載せ、内径４．５ｃｍの石英ガラス管の中で、触媒活性化のため、水素（Ｈ２）とヘリウム（Ｈｅ）との混合ガス（水素分圧：２０体積％）を１００ｓｃｃｍ（ｃｃ／ｍｉｎ）流しながら５００℃で２時間還元した。その後、エチレン（Ｃ２Ｈ４）と水素（Ｈ２）との混合ガス（水素分圧：２０体積％）を１００ｓｃｃｍ流しながら５８０℃の温度で１時間反応させて、所定量のヘリングボーン構造の繊維状ナノ炭素を作製した。 (1) Fibrous nanocarbon production process 50 mg of ultrafine nickel catalyst prepared using a precipitation method is placed on a quartz glass boat (length 10 mm, width 2.5 mm, depth 1.5 mm), and an inner diameter of 4 In a 5 cm quartz glass tube, for catalyst activation, a mixed gas of hydrogen (H 2 ) and helium (He) (hydrogen partial pressure: 20 vol%) flows at 500 ° C. while flowing 100 sccm (cc / min). For 2 hours. Thereafter, the mixture is reacted at a temperature of 580 ° C. for 1 hour while flowing a mixed gas of ethylene (C 2 H 4 ) and hydrogen (H 2 ) (hydrogen partial pressure: 20% by volume) at 100 sccm, and a predetermined amount of herringbone structure is obtained. Fibrous nanocarbon was prepared.
（２）鉄系遷移金属触媒粒子付着工程
　その後、硝酸鉄（ＩＩＩ）九水和物の一定量を純水に溶解した溶液に、繊維状ナノ炭素を浸漬した後、繊維状ナノ炭素を乾燥させることにより、繊維状ナノ炭素に平均粒径が２０ｎｍの鉄系遷移金属触媒粒子を付着させた。 (2) Iron-based transition metal catalyst particle adhering step Thereafter, the fibrous nanocarbon is dipped in a solution in which a certain amount of iron nitrate (III) nonahydrate is dissolved in pure water, and then the fibrous nanocarbon is dried. As a result, iron-based transition metal catalyst particles having an average particle diameter of 20 nm were adhered to the fibrous nanocarbon.
（３）トンネル型メソ気孔形成工程
　その後、内径５ｃｍの石英ガラス管の中で、２００℃～６００℃の温度範囲で繊維状ナノ炭素に酸化性ガスとしての空気を接触させることにより、繊維状ナノ炭素に、平均孔径が２０ｎｍ、平均深さが２０ｎｍのトンネル型メソ気孔を形成した。トンネル型メソ気孔形成工程終了後、残存炭素量、酸素含有量及びＢＥＴ比表面積を測定した。なお、残存炭素量は、重量減少率より算出し、酸素含有量は、ＣＨＮ元素分析結果より算出した。 (3) Tunnel-type mesopore formation step Thereafter, fibrous nanocarbon is brought into contact with fibrous nanocarbon in a temperature range of 200 ° C. to 600 ° C. in a quartz glass tube having an inner diameter of 5 cm. Tunnel-type mesopores having an average pore diameter of 20 nm and an average depth of 20 nm were formed in carbon. After completion of the tunnel-type mesopore formation step, the residual carbon content, oxygen content, and BET specific surface area were measured. The residual carbon amount was calculated from the weight reduction rate, and the oxygen content was calculated from the CHN elemental analysis results.
　表１は、トンネル型メソ気孔形成工程中における空気の流量及び空気との接触時間と、トンネル型メソ気孔形成工程終了後における残存炭素量、酸素含有量及びＢＥＴ比表面積との関係を示す表である。 Table 1 is a table showing the relationship between the air flow rate and the contact time with air during the tunnel-type mesopore formation process and the residual carbon amount, oxygen content, and BET specific surface area after the tunnel-type mesopore formation process. is there.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　表１に示すように、トンネル型メソ気孔形成工程中における空気の流量を多くしたり、空気との接触時間を長くしたりすれば、残存炭素量が減少し、酸素含有量が増加し、ＢＥＴ比表面積が大きくなることがわかる。実施例１においては、空気の流量を１５０ｓｃｃｍとするとともに空気との接触時間を２時間とし、残存炭素量が７２％、酸素含有量が１１．７％、ＢＥＴ比表面積が２２２ｍ２／ｇとなる条件（表１の上から４行目の条件）でトンネル型メソ気孔形成工程を行った。 As shown in Table 1, if the air flow rate in the tunnel mesopore formation process is increased or the contact time with the air is increased, the residual carbon amount decreases, the oxygen content increases, and the BET It can be seen that the specific surface area increases. In Example 1, the flow rate of air is 150 sccm, the contact time with air is 2 hours, the residual carbon content is 72%, the oxygen content is 11.7%, and the BET specific surface area is 222 m 2 / g. The tunnel-type mesopore formation process was performed under the conditions (conditions on the fourth line from the top of Table 1).
（４）貴金属触媒粒子担持工程
　その後、繊維状ナノ炭素を２０％の塩酸に浸漬することにより繊維状ナノ炭素から鉄系遷移金属触媒粒子を除去した後、当該繊維状ナノ炭素を塩化白金酸六水和物及び塩化ルテニウム（ＩＩＩ）ｎ水和物を含有する水溶液に浸漬した。さらにその後、テトラヒドロホウ酸ナトリウムを用いて上記貴金属塩を化学還元することにより、繊維状ナノ炭素に貴金属触媒粒子を担持させた。貴金属触媒粒子１３０の平均粒径は３ｎｍであった。 (4) Noble metal catalyst particle supporting step After the iron-based transition metal catalyst particles are removed from the fibrous nanocarbon by immersing the fibrous nanocarbon in 20% hydrochloric acid, the fibrous nanocarbon is converted to chloroplatinic acid hexa It was immersed in an aqueous solution containing a hydrate and ruthenium (III) chloride n hydrate. Thereafter, the noble metal catalyst particles were supported on the fibrous nanocarbon by chemically reducing the noble metal salt using sodium tetrahydroborate. The average particle diameter of the noble metal catalyst particles 130 was 3 nm.
［比較例１］
　以下の繊維状ナノ炭素作製工程と、鉄系遷移金属触媒粒子付着工程と、トンネル型メソ気孔形成工程と、貴金属触媒粒子担持工程とをこの順序で含む燃料電池用触媒の製造方法を実施することにより、比較例１に係る燃料電池用触媒を作製した。このうち、繊維状ナノ炭素作製工程、鉄系遷移金属触媒粒子付着工程及び貴金属触媒粒子担持工程は、実施例１と同じであり、トンネル型メソ気孔形成工程は、実施例１とは異なる。トンネル型メソ気孔形成工程は、以下のとおりである。 [Comparative Example 1]
Implementing a method for producing a catalyst for a fuel cell comprising the following fibrous nanocarbon production step, iron-based transition metal catalyst particle adhesion step, tunnel-type mesopore formation step, and noble metal catalyst particle support step in this order Thus, a fuel cell catalyst according to Comparative Example 1 was produced. Among these, the fibrous nanocarbon production step, the iron-based transition metal catalyst particle adhesion step, and the noble metal catalyst particle supporting step are the same as in Example 1, and the tunnel-type mesopore forming step is different from that in Example 1. The tunnel-type mesopore forming process is as follows.
（３）トンネル型メソ気孔形成工程
　その後、内径５ｃｍの石英ガラス管の中で、８５０℃の温度で３時間繊維状ナノ炭素に水素ガス／ヘリウムガスの混合ガス（１：１）を接触させることにより、繊維状ナノ炭素に、平均孔径が２０ｎｍ程度、平均深さが２０ｎｍのトンネル型メソ気孔を形成した。 (3) Tunnel-type mesopore formation step Thereafter, a mixed gas (1: 1) of hydrogen gas / helium gas is brought into contact with fibrous nanocarbon at a temperature of 850 ° C. for 3 hours in a quartz glass tube having an inner diameter of 5 cm. Thus, tunnel-type mesopores having an average pore diameter of about 20 nm and an average depth of 20 nm were formed in the fibrous nanocarbon.
［比較例２］
　以下の繊維状ナノ炭素作製工程と、貴金属触媒粒子担持工程とをこの順序で含む燃料電池用触媒の製造方法を実施することにより、比較例２に係る燃料電池用触媒を作製した。すなわち、比較例２においては、繊維状ナノ炭素作製工程で作製された繊維状ナノ炭素をそのまま用いて当該繊維状ナノ炭素に貴金属触媒粒子を担持させた。なお、繊維状ナノ炭素作製工程及び貴金属触媒粒子担持工程は、実施例１と同じである。 [Comparative Example 2]
A fuel cell catalyst according to Comparative Example 2 was produced by carrying out a method for producing a fuel cell catalyst comprising the following fibrous nanocarbon production step and noble metal catalyst particle supporting step in this order. That is, in Comparative Example 2, noble metal catalyst particles were supported on the fibrous nanocarbon using the fibrous nanocarbon produced in the fibrous nanocarbon production step as it was. The fibrous nanocarbon production process and the noble metal catalyst particle supporting process are the same as those in Example 1.
［比較例３］
　Ｅ－ＴＥＫ社から販売されている、カーボン微粒子に貴金属触媒粒子を担持させた燃料電池用触媒を比較例３とした。 [Comparative Example 3]
Comparative Example 3 was a fuel cell catalyst sold by E-TEK in which noble metal catalyst particles were supported on carbon fine particles.
２．単電池評価
（１）スラリーの作製
　実施例１及び比較例１～３に係る燃料電池用触媒のそれぞれに炭素含有ペーストを混合してスラリーを作製した。
　表２は、実施例１及び比較例１～３における貴金属使用量を示す表である。表２に示すように、貴金属使用量（すなわちスラリーにおける貴金属触媒粒子の全重量と炭素の全重量との和に占める貴金属触媒粒子の全重量の比率）は、実施例１並びに比較例１及び２の場合は４０％であり、比較例３の場合は６０％である。 2. Cell Evaluation (1) Preparation of Slurry A carbon-containing paste was mixed with each of the fuel cell catalysts according to Example 1 and Comparative Examples 1 to 3 to prepare a slurry.
Table 2 is a table showing the amount of noble metal used in Example 1 and Comparative Examples 1 to 3. As shown in Table 2, the amount of noble metal used (that is, the ratio of the total weight of the noble metal catalyst particles to the sum of the total weight of the noble metal catalyst particles and the total weight of carbon in the slurry) was determined in Example 1 and Comparative Examples 1 and 2. In the case of Comparative Example 3, it is 40%.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
（２）単電池評価系の作製
　図６は、単電池評価系２００を説明するために示す図である。
　まず、「実施例１並びに比較例１～３に係る燃料電池用触媒」、「ナフィオン１１５（デュポン株式会社製、ナフィオンはデュポン株式会社の商標。）及びナフィオン分散液２０重量％」並びに「市販のＰｔ－ｂｌａｃｋ（Johnson Matthey社製、６ｍｇ／ｃｍ２）」を積層し、これらを１３５℃の温度下、１００ｋｇ／ｃｍ２の圧力を１０分間印加することにより電極接合体（ＭＥＡ）２０４を作製した。実施例１並びに比較例１～３に係る燃料電池用触媒が燃料極触媒２１２となり、「ナフィオン１１５」及びナフィオン分散液が電解質膜２３０となり、市販のＰｔ－ｂｌａｃｋが空気極触媒２２２となる。電極接合体２０４の面積は、２５ｍｍ×２５ｍｍである。 (2) Production of Single Cell Evaluation System FIG. 6 is a diagram for explaining the single cell evaluation system 200.
First, “catalyst for fuel cell according to Example 1 and Comparative Examples 1 to 3”, “Nafion 115 (manufactured by DuPont, Nafion is a trademark of DuPont Co., Ltd.) and Nafion dispersion 20% by weight” and “commercially available Pt-black (manufactured by Johnson Matthey, 6 mg / cm 2 ) ”was laminated, and an electrode assembly (MEA) 204 was produced by applying a pressure of 100 kg / cm 2 for 10 minutes at a temperature of 135 ° C. . The fuel cell catalyst according to Example 1 and Comparative Examples 1 to 3 becomes the fuel electrode catalyst 212, “Nafion 115” and the Nafion dispersion become the electrolyte membrane 230, and the commercially available Pt-black becomes the air electrode catalyst 222. The area of the electrode assembly 204 is 25 mm × 25 mm.
　その後、電極接合体２０４に燃料極集電体２１４及びを空気極集電体２２４を取り付けることにより、燃料電池（ダイレクトメタノール型燃料電池）２０２を作製し、当該燃料電池２０２を用いて図６に示すような単電池評価系２００を作製した。 Thereafter, a fuel cell (direct methanol fuel cell) 202 is fabricated by attaching the fuel electrode current collector 214 and the air electrode current collector 224 to the electrode assembly 204, and FIG. A single cell evaluation system 200 as shown was produced.
（３）単電池評価
　単電池評価系２００における燃料極２１０に２Ｍのメタノールを４ｍｌ／分の流量で供給するとともに、空気極２２０に酸素を２００ｍｌ／分の流量で供給したときの電圧及び電流を電圧計２４２及び電流計２４４を用いて、負荷２４０の抵抗値を変化させながら測定し、単電池評価を行った。 (3) Single Cell Evaluation 2 M methanol is supplied to the fuel electrode 210 in the single cell evaluation system 200 at a flow rate of 4 ml / min, and the voltage and current when oxygen is supplied to the air electrode 220 at a flow rate of 200 ml / min. Using a voltmeter 242 and an ammeter 244, measurement was performed while changing the resistance value of the load 240, and a single cell was evaluated.
　図７～図１０は、単電池評価の結果を示す図である。図７は、実施例１に係る燃料電池用触媒を用いた単電池における産生電力密度を示す図であり、図８は、比較例１に係る燃料電池用触媒を用いた単電池における産生電力密度を示す図であり、図９は、比較例２に係る燃料電池用触媒を用いた単電池における産生電力密度を示す図であり、図１０は、比較例３に係る燃料電池用触媒を用いた単電池における産生電力密度を示す図である。 7 to 10 are diagrams showing the results of cell evaluation. FIG. 7 is a diagram showing the produced power density in the unit cell using the fuel cell catalyst according to Example 1, and FIG. 8 is the produced power density in the unit cell using the fuel cell catalyst according to Comparative Example 1. FIG. 9 is a diagram showing a generated power density in a unit cell using the fuel cell catalyst according to Comparative Example 2, and FIG. 10 is a graph using the fuel cell catalyst according to Comparative Example 3. It is a figure which shows the production electric power density in a cell.
　表３は、単電池評価結果を示す表である。表３においては、実施例１並びに比較例１～３における最大産生電力密度を示す。
Figure JPOXMLDOC01-appb-T000003
 Table 3 is a table showing the cell evaluation results. Table 3 shows the maximum production power density in Example 1 and Comparative Examples 1 to 3.
Figure JPOXMLDOC01-appb-T000003
　図７～図１０及び表３からもわかるように、実施例１に係る燃料電池用触媒を用いた単電池は、比較例１～３に係る燃料電池用触媒を用いた単電池に比べて最大産生電力密度が高く、ひいては燃料電池効率が高いことがわかった。　 As can be seen from FIGS. 7 to 10 and Table 3, the unit cell using the fuel cell catalyst according to Example 1 is the largest compared to the unit cell using the fuel cell catalyst according to Comparative Examples 1 to 3. It was found that the produced power density is high and the fuel cell efficiency is high. *
　以上、本発明の燃料電池用触媒の製造方法、電極接合体及び燃料電池を上記の実施形態に基づいて説明したが、本発明は上記の実施形態に限定されるものではなく、その要旨を逸脱しない範囲において種々の態様において実施することが可能であり、例えば次のような変形も可能である。 As mentioned above, although the manufacturing method of the catalyst for fuel cells of this invention, the electrode assembly, and the fuel cell were demonstrated based on said embodiment, this invention is not limited to said embodiment, It deviates from the summary. The present invention can be implemented in various modes as long as it is not, for example, the following modifications are possible.
（１）上記実施形態においては、繊維状ナノ炭素として、ヘリングボーン構造を有する繊維状ナノ炭素を用いたが、本発明はこれに限定されるものではない。例えば、プレートレット構造を有する繊維状ナノ炭素を用いることもできる。 (1) In the said embodiment, although fibrous nanocarbon which has a herringbone structure was used as fibrous nanocarbon, this invention is not limited to this. For example, fibrous nanocarbon having a platelet structure can be used.
（２）上記実施例においては、貴金属使用量として４０重量％のものを用いたが、本発明はこれに限定されるものではない。例えば、貴金属使用量として４０重量％以上のものを用いることもできるし、４０重量％未満のものを用いることもできる。 (2) In the above embodiment, 40% by weight of noble metal was used, but the present invention is not limited to this. For example, the amount of noble metal used may be 40% by weight or more, or less than 40% by weight.
（３）上記実施例においては、本発明の燃料電池用触媒によって製造された燃料電池用触媒を燃料極触媒の材料として用いたが、本発明はこれに限定されるものではない。例えば、空気極触媒の材料として用いることもできる。 (3) In the above embodiment, the fuel cell catalyst produced by the fuel cell catalyst of the present invention is used as the material for the fuel electrode catalyst, but the present invention is not limited to this. For example, it can be used as a material for an air electrode catalyst.

Claims (12)

  1. 　金属触媒又は合金触媒存在下のもとで４００℃～１２００℃の温度範囲で炭素含有ガスを熱分解反応させることにより、繊維状ナノ炭素を作製する繊維状ナノ炭素作製工程と、
    　前記繊維状ナノ炭素の表面に鉄系遷移金属触媒粒子を付着させる鉄系遷移金属触媒粒子付着工程と、
    　２００℃～６００℃の温度範囲で前記繊維状ナノ炭素に酸化性ガスを接触させることにより、前記繊維状ナノ炭素にトンネル型メソ気孔を形成するトンネル型メソ気孔形成工程と、
    　前記トンネル型メソ気孔中に貴金属触媒粒子を担持させる貴金属触媒粒子担持工程とをこの順序で含むことを特徴とする燃料電池用触媒の製造方法。     A fibrous nanocarbon production process for producing fibrous nanocarbon by thermally decomposing a carbon-containing gas in the temperature range of 400 ° C. to 1200 ° C. in the presence of a metal catalyst or an alloy catalyst;
    An iron-based transition metal catalyst particle attaching step of attaching iron-based transition metal catalyst particles to the surface of the fibrous nanocarbon; and
    A tunnel-type mesopore forming step for forming a tunnel-type mesopore in the fibrous nanocarbon by bringing an oxidizing gas into contact with the fibrous nanocarbon in a temperature range of 200 ° C to 600 ° C;
    A method for producing a fuel cell catalyst, comprising a noble metal catalyst particle supporting step of supporting noble metal catalyst particles in the tunnel type mesopores in this order.
  2. 　請求項１に記載の燃料電池用触媒の製造方法において、
    　前記繊維状ナノ炭素作製工程で作製する繊維状ナノ炭素は、ヘリングボーン構造を有する繊維状ナノ炭素又はプレートレット構造を有する繊維状ナノ炭素であることを特徴とする燃料電池用触媒の製造方法。     In the manufacturing method of the catalyst for fuel cells of Claim 1,
    The method for producing a fuel cell catalyst, wherein the fibrous nanocarbon produced in the fibrous nanocarbon production step is a fibrous nanocarbon having a herringbone structure or a fibrous nanocarbon having a platelet structure.
  3. 　請求項１又は２に記載の燃料電池用触媒の製造方法において、
    　前記貴金属触媒粒子は、平均粒径が２ｎｍ～５ｎｍの範囲内にあり、
    　前記トンネル型メソ気孔は、平均孔径が２．５ｎｍ～１００ｎｍの範囲内にあり、平均深さが１０ｎｍ以上の範囲内にあることを特徴とする燃料電池用触媒の製造方法。     In the manufacturing method of the catalyst for fuel cells of Claim 1 or 2,
    The noble metal catalyst particles have an average particle diameter in the range of 2 nm to 5 nm,
    The method for producing a fuel cell catalyst, wherein the tunnel type mesopores have an average pore diameter in a range of 2.5 nm to 100 nm and an average depth in a range of 10 nm or more.
  4. 　請求項１～３のいずれかに記載の燃料電池用触媒の製造方法において、
    　前記鉄系遷移金属触媒粒子は、平均粒径が２．５ｎｍ～１００ｎｍの範囲内にあることを特徴とする燃料電池用触媒の製造方法。     The method for producing a fuel cell catalyst according to any one of claims 1 to 3,
    The method for producing a fuel cell catalyst, wherein the iron-based transition metal catalyst particles have an average particle diameter in a range of 2.5 nm to 100 nm.
  5. 　請求項１～４のいずれかに記載の燃料電池用触媒の製造方法において、
    　前記繊維状ナノ炭素作製工程で作製する繊維状ナノ炭素は、ＢＥＴ比表面積が２００ｍ２／ｇ以上であることを特徴とする燃料電池用触媒の製造方法。     The method for producing a fuel cell catalyst according to any one of claims 1 to 4,
    The method for producing a fuel cell catalyst, wherein the fibrous nanocarbon produced in the fibrous nanocarbon production step has a BET specific surface area of 200 m 2 / g or more.
  6. 　請求項１～５のいずれかに記載の燃料電池用触媒の製造方法において、
    　前記酸化性ガスは、空気、不活性ガスと酸素ガスとの混合ガス又は純酸素ガスであることを特徴とする燃料電池用触媒の製造方法。     In the method for producing a fuel cell catalyst according to any one of claims 1 to 5,
    The method for producing a fuel cell catalyst, wherein the oxidizing gas is air, a mixed gas of inert gas and oxygen gas, or pure oxygen gas.
  7. 　請求項１～６のいずれかに記載の燃料電池用触媒の製造方法において、
    　前記トンネル型メソ気孔形成工程終了後の繊維状ナノ炭素には、０．５重量％～２０重量％の酸素が含まれていることを特徴とする燃料電池用触媒の製造方法。     The method for producing a fuel cell catalyst according to any one of claims 1 to 6,
    The method for producing a catalyst for a fuel cell, characterized in that the fibrous nanocarbon after the completion of the tunnel-type mesopore formation step contains 0.5 wt% to 20 wt% of oxygen.
  8. 　請求項１～７のいずれかに記載の燃料電池用触媒の製造方法において、
    　前記鉄系遷移金属触媒粒子は、Ｆｅ、Ｎｉ若しくはＣｏ又はこれらの合金の微粒子からなることを特徴とする燃料電池用触媒の製造方法。     The method for producing a fuel cell catalyst according to any one of claims 1 to 7,
    The method for producing a fuel cell catalyst, wherein the iron-based transition metal catalyst particles comprise fine particles of Fe, Ni, Co, or an alloy thereof.
  9. 　請求項１～８のいずれかに記載の燃料電池用触媒の製造方法において、
    　前記貴金属触媒粒子は、Ｐｔ、Ｒｕ若しくはＰｄ又はこれらの貴金属を含む合金の微粒子からなることを特徴とする燃料電池用触媒の製造方法。     The method for producing a fuel cell catalyst according to any one of claims 1 to 8,
    The method for producing a fuel cell catalyst, wherein the noble metal catalyst particles are made of fine particles of Pt, Ru, Pd or an alloy containing these noble metals.
  10. 　請求項１～９のいずれかに記載の燃料電池用触媒の製造方法によって製造される燃料電池用触媒に炭素含有ペーストを混合して得られるスラリーを用いて製造される電極接合体であって、
    　前記スラリーにおける貴金属触媒粒子の全重量と炭素の全重量との和に占める前記貴金属触媒粒子の全重量の比率は、４０％以下であることを特徴とする電極接合体。     An electrode assembly produced using a slurry obtained by mixing a carbon-containing paste with a fuel cell catalyst produced by the method for producing a fuel cell catalyst according to any one of claims 1 to 9,
    A ratio of the total weight of the noble metal catalyst particles to the sum of the total weight of the noble metal catalyst particles and the total weight of carbon in the slurry is 40% or less.
  11. 　請求項１０に記載の電極接合体を備える燃料電池であって、
    　９０℃運転時に１６０ｍＷ／ｃｍ２以上の電力を産生可能であることを特徴とする燃料電池。     A fuel cell comprising the electrode assembly according to claim 10,
    A fuel cell capable of producing an electric power of 160 mW / cm 2 or more during operation at 90 ° C.
  12. 　請求項１１に記載の燃料電池において、
    　９０℃運転時に１８５ｍＷ／ｃｍ２以上の電力を産生可能であることを特徴とする燃料電池。     The fuel cell according to claim 11, wherein
    A fuel cell characterized by being capable of producing electric power of 185 mW / cm 2 or more during operation at 90 ° C.
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