WO2020235322A1 - Fuel cell cathode, method for producing same and solid polymer fuel cell equipped with fuel cell cathode - Google Patents
Fuel cell cathode, method for producing same and solid polymer fuel cell equipped with fuel cell cathode Download PDFInfo
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- WO2020235322A1 WO2020235322A1 PCT/JP2020/018212 JP2020018212W WO2020235322A1 WO 2020235322 A1 WO2020235322 A1 WO 2020235322A1 JP 2020018212 W JP2020018212 W JP 2020018212W WO 2020235322 A1 WO2020235322 A1 WO 2020235322A1
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- WIPO (PCT)
- Prior art keywords
- catalyst
- fuel cell
- cathode electrode
- metal oxide
- composite metal
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- 239000000446 fuel Substances 0.000 title claims abstract description 53
- 229920000642 polymer Polymers 0.000 title claims abstract description 30
- 238000004519 manufacturing process Methods 0.000 title claims description 8
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- 239000003054 catalyst Substances 0.000 claims abstract description 164
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- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 67
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- 239000002923 metal particle Substances 0.000 claims abstract description 49
- 239000004020 conductor Substances 0.000 claims abstract description 47
- 229910052697 platinum Inorganic materials 0.000 claims abstract description 25
- 239000005518 polymer electrolyte Substances 0.000 claims abstract description 25
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 68
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- 229910006404 SnO 2 Inorganic materials 0.000 claims description 25
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- OEIMLTQPLAGXMX-UHFFFAOYSA-I tantalum(v) chloride Chemical compound Cl[Ta](Cl)(Cl)(Cl)Cl OEIMLTQPLAGXMX-UHFFFAOYSA-I 0.000 claims description 5
- 229910021389 graphene Inorganic materials 0.000 claims description 4
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- AXZWODMDQAVCJE-UHFFFAOYSA-L tin(II) chloride (anhydrous) Chemical compound [Cl-].[Cl-].[Sn+2] AXZWODMDQAVCJE-UHFFFAOYSA-L 0.000 claims description 3
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- HPGGPRDJHPYFRM-UHFFFAOYSA-J tin(iv) chloride Chemical compound Cl[Sn](Cl)(Cl)Cl HPGGPRDJHPYFRM-UHFFFAOYSA-J 0.000 description 2
- NWUYHJFMYQTDRP-UHFFFAOYSA-N 1,2-bis(ethenyl)benzene;1-ethenyl-2-ethylbenzene;styrene Chemical compound C=CC1=CC=CC=C1.CCC1=CC=CC=C1C=C.C=CC1=CC=CC=C1C=C NWUYHJFMYQTDRP-UHFFFAOYSA-N 0.000 description 1
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- PIBWKRNGBLPSSY-UHFFFAOYSA-L palladium(II) chloride Chemical compound Cl[Pd]Cl PIBWKRNGBLPSSY-UHFFFAOYSA-L 0.000 description 1
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Images
Classifications
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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
- 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
- B01J23/76—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
- B01J23/84—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36 with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/847—Vanadium, niobium or tantalum or polonium
-
- 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
-
- B01J35/51—
-
- 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
-
- 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
- B01J37/16—Reducing
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/10—Fuel cells with solid electrolytes
-
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Definitions
- the present invention relates to a cathode electrode for a fuel cell, a method for manufacturing the same, and a polymer electrolyte fuel cell provided with a cathode electrode for a fuel cell.
- ionomer fluorine ion exchange resin
- a perfluorocarbon polymer having a strongly acidic sulfonic acid group in the side chain is used in order to enhance proton conductivity.
- Patent Documents 1, 2 and 3 a polymer electrolyte fuel cell and an electrode layer treated with a fluororesin or a fluorine-based silane coupling agent for coating a catalyst are proposed.
- the coating treatment with a fluororesin and a fluorosilane was not sufficient from the viewpoint of durability because the fluororesin was peeled off and the siloxane bond was hydrolyzed due to the fluctuation of the traveling load of the automobile and the start / stop.
- a catalyst called a three-phase interface, ionomer and oxygen (in other words, hydrogen ions, oxygen, and electrons are associated with each other on the surface of the catalyst metal particles) are associated with each other during catalysis.
- the purpose is to have more catalytic metal particles to have a reaction site to improve the effective utilization rate of platinum. Furthermore, it is to enable the continuous retention of the reaction site at the three-phase interface even in the presence of overvoltages in the traveling load fluctuation cycle and the start / stop cycle of the automobile.
- Patent Document 4 when the oxygen absorber composed of the pyrochlor type Ce 2 Zr 2 O 7 is separately present on the surface of the catalyst-supporting conductor without being in direct contact with the catalyst metal particles, Oxygen is easily dissolved in the generated water, and the supply to the reaction site at the three-phase interface on the surface of the catalyst metal particles is reduced. Further, since the oxygen absorber made of the pyrochloro type Ce 2 Zr 2 O 7 has low electron conductivity, the internal resistance of the cathode electrode increases, and the overvoltage of the traveling load fluctuation cycle and the start / stop cycle of the automobile becomes high. , Oxidation and elution of platinum, decomposition of sulfonic acid groups of ionomer and corrosion of catalyst-bearing conductors (conductive carbon).
- the metal oxide having protrusions is a catalyst metal so that the conduction of hydrogen ions, the conduction of electrons and oxygen can be associated with the surface of the catalyst metal particles to continuously form the site of the three-phase interface.
- the cathode electrode for a fuel cell of the present invention has a catalyst layer composed of a catalyst-supporting conductor and a polymer electrolyte, and the surface of the catalyst-supporting conductor has protrusions. It is covered with a composite metal oxide, and catalyst metal particles are supported on the conductive composite metal oxide.
- the height of the protrusions of the conductive composite metal oxide may be 5 nm to 15 nm.
- the conductive composite metal oxide may have a water repellency of 140 degrees or more at a contact angle with water.
- the catalyst-supported conductor may have a specific resistance of 0.2 ⁇ ⁇ cm or less.
- the conductive composite metal oxide may be an oxygen absorber.
- the conductive composite metal oxide may be a p-type semiconductor.
- the conductive composite metal oxide may contain Ta-doped SnO 2 (0.01% by mass ⁇ Ta ⁇ 1.0% by mass).
- the catalyst metal particles may have a core-shell structure composed of a Pt shell layer.
- the core layer of the core-shell structure may be made of Pd and an alloy selected from at least one of Pt, Ru and Co.
- the catalyst-supporting conductor may consist of at least one selected from conductive carbon, graphite, graphene and carbon alloy.
- the method for manufacturing a cathode electrode for a fuel cell of the present invention is the above-mentioned method for manufacturing a cathode electrode for a fuel cell of the present invention, and the suspension of the catalyst-supporting conductor , Tin chloride (II) and tantalum chloride (V) are added, and the pH is controlled to 1.5 to 2.0 to obtain the conductive composite metal oxide.
- the core layer of the catalyst metal particles may be formed on the surface of the protruding conductive composite metal oxide that covers the surface of the catalyst-supporting conductor by the first reduction step.
- the Pt shell layer of the catalyst metal particles may be formed by the second reduction step.
- the polymer electrolyte fuel cell of the present invention has a polymer arranged between the anode electrode, the cathode electrode of the present invention, and the anode electrode and the cathode electrode. It has an electrolyte membrane.
- the conductive composite metal oxide may contain Ta-doped SnO 2 (0.01% by mass ⁇ Ta ⁇ 1.0% by mass).
- a composite metal oxide composed of a pyrochloro-type Sn 2 Ta 2 O 7 having a protrusion and / or a crystal of Sn 2 Nb 2 O 7 has a long-lasting water repellency.
- FIG. 1 shows a conceptual diagram of the catalyst carrier conductor, the composite oxide, the catalyst metal particles, and the ionomer in the cathode electrode of the present invention.
- FIG. 2 shows a conceptual diagram of a reaction site at a three-phase interface due to the movement of hydrogen ions, electrons, and oxygen molecules onto the surface of the catalyst metal particles.
- FIG. 3 shows a conceptual diagram of deterioration behavior during power generation in a conventional cathode electrode.
- FIG. 4 shows a conceptual diagram of the core-shell type catalyst of the present invention.
- the present invention by forming a composite metal oxide having protrusions of 5 nm to 15 nm on the surface of the catalyst-supported conductor, the wettability with ionomer is good, the platinum effectiveness rate is high, and water can be discharged. In addition, the catalyst and the ionomer can be brought into close contact with each other when the catalyst is operated, and the continuous water repellency can be maintained.
- the composite metal oxide has a crystal structure of pyrochlore type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 . The catalyst metal particles are in contact with the surface of the metal oxide and are not dissolved in the water generated by oxygen, so that the catalyst metal particles can be efficiently supplied. is there.
- the composite metal oxide having an oxygen absorbing / releasing property having a crystal structure of pyrochlorotype Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 is a catalyst-supporting conductor and a catalyst metal. It is provided in contact with the particles and has electron conductivity, so that electrons can be supplied to the reaction site at the three-phase interface on the surface of the catalyst metal particles. At the same time, the metal oxide can prevent corrosion of the catalyst-supported conductor.
- the present invention is an invention of a cathode electrode for a fuel cell having a catalyst layer composed of a catalyst-supporting conductor and an ionomer, and is a pyrochloro-type Sn 2 having a protrusion on the surface of the catalyst-supporting conductor.
- Ta 2 O 7, Sn 2 Nb 2 O 7 and / or conductive composite metal oxide of the crystal structure of Ta-doped SnO 2 are formed, the catalyst metal particles are supported on the surface of the further conductive complex metal oxides Is preferable.
- the cathode electrode of the present invention the conductive composite metal comprising a crystal structure of the catalyst carrier conductive pyrochlore type surface fine protruding Sn 2 Ta 2 O 7, Sn 2 Nb 2 O 7 and / or Ta-doped SnO 2
- the oxide is further supported, it has long-lasting water repellency due to the formation of protrusions, and since the catalyst metal particles are supported on the surface of the conductive composite metal oxide, it is conductive to the catalyst metal particles.
- the oxygen defect of the sex composite metal oxide conducts electrons, and the oxygen carrier of the crystal structure of the pyrochloro type Sn 2 Ta 2 O 7 , Sn 2 Nb 2 O 7 and / or Ta-doped Sn O 2 causes oxygen carriers.
- a diffusion path for oxygen molecules is secured directly to the catalytic metal particles.
- the electron conductivity and oxygen carrier properties of the crystal structure of pyrochloro-type Sn 2 Ta 2 O 7 , Sn 2 Nb 2 O 7 and / or Ta-doped Sn O 2 electrons And oxygen molecules can be associated with the surface of the catalytic metal particles to increase the exchange current density in the electrode reaction and reduce overvoltage. That is, high electrode characteristics can be obtained.
- the overvoltage of the oxygen reduction reaction of the cathode electrode can be effectively reduced, so that the electrode characteristics of the cathode electrode can be improved.
- the shortage of oxygen gas occurs especially during operation of the fuel cell, but according to the present invention, high electrode characteristics can be maintained even during long-term operation.
- protrusions made of a conductive composite metal oxide having a height and an interval of 5 nm to 15 nm are formed on the surface of a catalyst carrier conductor having a particle size of 20 nm to 50 nm, and are resistant to corrosion by overvoltage and hydrogen peroxide. It made it possible to maintain durable water repellency that can be tolerated.
- the conductive composite metal oxide of the present invention has a pyrochlore-type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 crystal structure, holes are generated by oxygen defects and a P-type semiconductor is generated. It has characteristics and enables electron conductivity.
- the pyrochlore-type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 crystals that can be used in the present invention absorb and release oxygen due to oxygen defects in the crystals due to fluctuations in oxygen concentration in the vicinity.
- the oxygen carrier materials having a function of being able to reversibly repeat. That is, oxygen can be absorbed when the O 2 concentration is relatively high, and oxygen can be released in an atmosphere where the O 2 concentration is low.
- the catalyst-supported conductor in which the pyrochlore-type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 is supported on the surface is preferably porous carbon powder, graphite powder or graphene powder. ..
- the cathode electrode has a catalyst layer composed of a catalyst-supporting conductor and an ionomer, and the surface of the catalyst-supporting conductor has a pyrochlor-type Sn. It is preferable that an oxygen absorber composed of 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 , or Ta-doped SnO 2 which is not an oxygen absorber, and catalyst metal particles are further supported on the surface thereof. ..
- the cathode electrode of the present invention having excellent electrode characteristics for the oxygen reduction reaction described above, it is possible to construct a polymer electrolyte fuel cell having a high battery output. Further, as described above, in the cathode electrode of the present invention, the overvoltage of the traveling load fluctuation cycle and the start / stop cycle of the automobile becomes high, platinum oxidation and elution, decomposition of the sulfonic acid group of the ionomer, and catalyst-supported conductivity. Since the body (conductive carbon) can be prevented from corroding and has excellent durability, the polymer electrolyte fuel cell of the present invention provided with this can stably obtain a high battery output for a long period of time. It becomes.
- the surface of the catalyst carrier conductor is coated with a composite metal oxide having fine protrusions.
- Catalytic metal particles are supported on the surface of the composite metal oxide.
- the protrusions act as spacers, and the ionomer covers the tops of the protrusions with a uniform thickness.
- a pyrochlore-type Sn 2 Ta 2 O 7 and / or a Sn 2 Nb 2 O 7 conductive composite metal oxide having protrusions is supported on the surface of the catalyst-supporting conductor. Since the fine protrusions have continuous water repellency, the catalyst and the ionomer can maintain close contact even at high output, and many hydrogen ions can reach the catalyst metal particles.
- oxygen when the fuel cell has a low output, the amount of oxygen consumed by the catalyst is small, and the oxygen concentration near the oxygen absorber is high, so excess oxygen is stored in the oxygen absorber. On the other hand, since the amount of oxygen consumed by the catalyst is large and the oxygen concentration in the vicinity of the oxygen absorber is low, oxygen is directly transferred from the composite metal oxide to the catalyst metal particles, so that the influence of gas diffusion in the catalyst layer The performance of the fuel cell is further improved by reducing oxygen on the catalyst without receiving oxygen in the generated water and consuming oxygen.
- the electrode reaction proceeds at the site where the reaction gas, catalyst, and electrolyte meet, which is called the three-phase interface.
- the supply of oxygen to the three-phase interface is one important topic.
- the output of the battery is increased, a large amount of oxygen is required for the reaction, and if there is no oxygen in the vicinity of the catalyst, the power generation characteristics deteriorate sharply.
- a high concentration of oxygen is supplied, but as shown in FIG. 1, the actual reaction is carried out at the three-phase interface (near the catalyst), so if oxygen is not supplied here, it will be the same. I can't fully demonstrate my abilities.
- the output is increased, the oxygen consumption on the catalyst surface increases, but the diffusion rate of oxygen from the outside to the catalyst surface hardly changes.
- the cathode electrode of the polymer electrolyte fuel cell of the present invention includes a catalyst layer, and is preferably composed of a catalyst layer and a gas diffusion layer arranged adjacent to the catalyst layer.
- a constituent material of the gas diffusion layer for example, a porous body having electron conductivity (for example, carbon cloth or carbon paper) is used.
- a pyrochlor type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 having water repellency due to protrusions and conductivity and oxygen absorption / release property are present, and the cathode electrode
- the electrode reaction rate of the cathode electrode is improved by reducing the overvoltage with respect to the oxygen reduction reaction in the above.
- the electrode reaction rate of the cathode electrode can be improved by reducing the overvoltage with respect to the oxygen reduction reaction in the cathode electrode.
- the content of the pyrochlore-type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 composite metal oxide contained in the catalyst layer is the combination of the catalyst-supported conductor, the polymer electrolyte, and the catalyst metal particles.
- the amount is preferably 0.01 to 30% by mass, more preferably 0.01 to 20% by mass, based on the amount.
- the content of the pyrochlor type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 is less than 0.01% by mass, the water repellency, the electron conductivity and the oxygen absorption / release property are lowered.
- the content of the Ta-doped SnO 2 composite metal oxide contained in the catalyst layer is 0.01 to 30% by mass with respect to the total amount of the catalyst-supporting conductor, the polymer electrolyte, and the catalyst metal particles. It is preferably 0.01 to 20% by mass, and more preferably 0.01 to 20% by mass.
- the content of Ta-doped SnO 2 is less than 0.01% by mass, the water repellency, electron conductivity and oxygen absorption / release property are lowered, the ionomer and the catalyst metal particles are separated, oxygen is dissolved in the produced water, and the catalyst metal is dissolved.
- the Ta-doped SnO 2 preferably has a Ta content of 0.1 to 10% by mass, more preferably 0.5 to 5.0% by mass in SnO 2 .
- the Ta content is less than 0.1% by mass, the association of electrons with the catalyst metal at the three-phase interface is reduced, resulting in a decrease in power generation.
- the catalyst contained in the catalyst-supporting conductor of the cathode electrode of the present invention is not particularly limited, but platinum, platinum alloy or core-shell type (for example, the shell layer 6 surrounding the core layer 5 shown in FIG. 4 is platinum, core.
- Layer 5 is preferably an alloy selected from Pd, Pt, Ru and / or Co).
- the catalyst-supported conductor is not particularly limited, but a carbon material having a specific surface area of 200 m 2 / g or more is preferable. For example, carbon black, graphite or graphene is preferably used.
- a fluorine-containing ion exchange resin is preferable, and a sulfonic acid type perfluorocarbon polymer is particularly preferable.
- the sulfonic acid type perfluorocarbon polymer enables long-term chemically stable and rapid hydrogen ion conduction in the cathode electrode.
- the thickness of the catalyst layer of the cathode electrode of the present invention may be the same as that of the polymer solid electrolyte sandwiched between the ordinary anode electrode and the cathode electrode, and is preferably 1 to 50 ⁇ m, preferably 5 to 20 ⁇ m. Is more preferable.
- the overvoltage of the oxygen reduction reaction of the cathode electrode is usually very large compared to the overvoltage of the hydrogen oxidation reaction of the anode electrode, so that the generated hydrogen peroxide decomposes the sulfonic acid group of the ionomer.
- Oxidation and elution of catalyst metal and corrosion of catalyst carrier conductor are likely to occur, and as described above, the catalyst carrier conductor is coated with a composite metal oxide having water repellency, electron conductivity and oxygen absorption / release property due to the protrusion shape. It can be prevented by doing.
- the water-repellent effect of mosquito prevents the dissolution of oxygen in the generated water, and the oxygen absorption / release effect increases the oxygen concentration at the reaction site in the catalyst layer to suppress overvoltage, which is a continuous cathode. Improving the electrode characteristics of the electrodes is effective in stabilizing the output characteristics of the battery.
- the configuration of the anode electrode is not particularly limited, and for example, it may have a known configuration of a gas diffusion electrode.
- the polymer electrolyte membrane sandwiched between the anode electrode and the cathode electrode used in the polymer electrolyte fuel cell of the present invention is not particularly limited as long as it is an ion exchange membrane exhibiting good ionic conductivity under a wet state.
- the solid polymer material constituting the polymer electrolyte membrane for example, a perfluorocarbon polymer having a sulfonic acid group, a polysulfone resin, a perfluorocarbon polymer having a phosphonic acid group or a carboxylic acid group and the like can be used. Of these, a sulfonic acid type perfluorocarbon polymer is preferable.
- the polymer electrolyte membrane may be made of the same resin as the ionomer contained in the catalyst layer, or may be made of a different resin.
- the surface of the catalyst carrier conductor is covered with a composite metal oxide having protrusions in advance, and the catalyst metal particles are supported on the surface and the ionomer is dispersed in a solvent or dispersion.
- a solvent or dispersion medium for example, alcohol, fluorine-containing alcohol, fluorine-containing ether and the like can be used.
- the catalyst layer is formed by applying the coating liquid to an ion exchange membrane, a carbon cloth serving as a gas diffusion layer, or the like.
- the catalyst layer can also be formed on the polymer solid electrolyte membrane by applying the coating liquid to a separately prepared base material to form a coating layer and transferring the coating layer onto the polymer solid electrolyte membrane. ..
- the catalyst layer when the catalyst layer is formed on the gas diffusion layer, it is preferable to bond the catalyst layer and the polymer solid electrolyte membrane by an adhesion method, a hot press method, or the like. Further, when the catalyst layer is formed on the polymer solid electrolyte membrane, the cathode electrode may be formed only by the catalyst layer, but a gas diffusion layer may be further arranged adjacent to the catalyst layer to serve as the cathode electrode. Good.
- a separator having a normal gas flow path is arranged outside the cathode electrode, and a gas containing hydrogen is supplied to the anode electrode and a gas containing oxygen is supplied to the cathode electrode to the flow path to form a solid polymer type.
- a fuel cell is configured.
- the particle size distribution of the catalyst metal was measured by measuring 100 points using a transmission electron microscope (Titan Cubed G2 60-300, manufactured by FEI Company), and the average particle size was calculated by arithmetic mean.
- the shape (height, spacing) of the convex composite metal oxide of the present invention is the same as that of the particle size distribution of the catalyst metal, and a transmission electron microscope (Titan Cubed G2 60-300, manufactured by FEI) is used. Using, 100 points were measured, and the height and interval were calculated by arithmetic mean.
- Example 1 Prepare a mixture of Pt (5% by mass) / pyrochlore type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass) according to the following procedure, prepare MEA, assemble MEA into the cell, and evaluate the performance. did.
- Tin (II) chloride and tantalum (V) chloride were dissolved in pure water in a predetermined amount and stirred for 2 hours.
- Carbon black (Ketjen Black EC300J, BET specific surface area 800 g / m2, manufactured by Lion Specialty Chemicals Co., Ltd.) was prepared into powder, and a predetermined amount was added to pure water and stirred to prepare a suspension. ..
- the solution of (1) was slowly added to the suspension with stirring to adjust the pH to 1.5 with dilute hydrochloric acid, and the state was maintained for 3 hours. Then, filtration and washing with water were repeated three times to obtain a carbon black powder in which the carbon black particles were coated with Sn 2 Ta 2 O 7 .
- a catalyst ink of 0.0% by mass, Pt (5% by mass) / pyrochloro type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass) was prepared.
- the above catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ). It was used as an electrode film.
- Example 2 the core-shell type catalyst metal is the same as in Example 1 except that the catalyst metal is changed from the Pt single metal to the core-shell type catalyst metal (shell layer Pt / core layer Pd / Ru / Co alloy).
- An MEA was prepared using (5% by mass) / pyrochlore type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass), and its performance was evaluated in a single cell.
- the core-shell catalyst metal was produced by the following procedure. (1) The carbon black powder coated with Sn 2 Ta 2 O 7 obtained in (3) of Example 1 was dispersed in pure water with stirring, and combined with a palladium chloride solution (1% by mass as Pd). A predetermined amount of a ruthenium chloride solution (1% by mass as Ru) and a cobalt chloride solution (1% by mass as Co) were added. (2) A small amount of ethanol was slowly added thereto, and the mixture was heated to 40 ° C. and kept for 3 hours. Pd, Ru and Co were reduced to the surface of the composite metal oxide of Sn 2 Ta 2 O 7 . Then, filtration and washing with water were repeated 3 times, dried at 80 ° C.
- the catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ) to obtain an electrode film.
- Example 3 is the same as in Example 2 except that the pyrochlore-type Sn 2 Ta 2 O 7 is replaced with Ta-doped SnO 2 , and the core-shell type catalyst metal (5% by mass) / Ta-doped SnO 2 (20%). ) / MEA using carbon black (75% by mass) was prepared, and the performance was evaluated with a single cell.
- the composite metal oxide of Ta-doped SnO 2 was prepared by the following procedure. (1) A predetermined amount of tin (II) chloride was dissolved in pure water and stirred for 2 hours. (2) Carbon black (Ketjen Black EC300J, BET specific surface area 800 g / m 2 , manufactured by Lion Specialty Chemicals Co., Ltd.) is prepared into powder, and a predetermined amount is added to pure water and stirred to prepare a suspension. did. (3) The solution of (1) was slowly added to the suspension with stirring to adjust the pH to 1.5 with dilute hydrochloric acid, and the state was maintained for 3 hours. (4) A predetermined amount of tantalum chloride (V) was dissolved in pure water and stirred for 2 hours.
- V tantalum chloride
- the tantalum (V) chloride solution was slowly added in a predetermined amount, heated to 30 ° C., and held for 3 hours.
- filtration and washing with water were repeated three times to obtain a carbon black powder coated with Ta-doped SnO 2 .
- a small amount of the carbon black powder coated with the Ta-doped SnO 2 was collected, dried at 80 ° C. for 12 hours, pulverized in a mortar, and then calcined in an atmospheric baking oven at 500 ° C. for 2 hours.
- the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 145 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.2 ⁇ ⁇ cm. (10) Next, the core-shell type catalyst (Pt / Pd / Ru / Co alloy) / Ta-doped SnO 2 / carbon black is mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount.
- an ionomer electrolyte solution Nafion D520
- Catalyst ink was prepared. (11) The catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ) to obtain an electrode film. (12) When the electrode membrane was completely dissolved and ICP analyzed, Pt was 0.05 mg / cm 2 , Pd was 0.03 mg / cm 2 , Ru was 0.10 mg / cm 2 , and Co was 0.11 mg / cm.
- the core-shell catalyst (Pt / Pd / Ru / Co alloy) / carbon black powder was observed with a transmission electron microscope, the core-shell catalyst (Pt / Pd / Ru / Co alloy) particles were observed. The average particle size of was 3 nm.
- the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 90 degrees.
- the specific resistance was measured using the pellet, it was 0.5 ⁇ ⁇ cm.
- the core-shell type catalyst (Pt / Pd / Ru / Co alloy) / carbon black is mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount (Nafion /).
- a catalyst ink having Carbon 1.0% by mass and a core-shell type catalyst (Pt / Pd / Ru / Co alloy) (5% by mass) / carbon black (95% by mass) was prepared.
- the catalyst ink is cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ). It was used as an electrode film.
- Comparative Example 1 MEA was prepared using TEC10E50E (50% by mass as Pt, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) in which platinum was supported on commercially available carbon black, and the MEA was assembled into a cell to evaluate its performance.
- TEC10E50E 50% by mass as Pt, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.
- the average particle size of the platinum catalyst metal particles was 4 nm.
- the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 90 degrees.
- the specific resistance was measured using the pellet, it was 0.01 ⁇ ⁇ cm.
- MEA was assembled in the cell and the performance was evaluated.
- Comparative Example 2 In Comparative Example 2, instead of the pyrochlore type Sn 2 Ta 2 O 7 , the pyrochlore type Ce 2 Zr 2 O 7 was used as the composite metal oxide, and the pyrochlore type Ce 2 Zr 2 O 7 was not supported with the catalyst metal particles. , The composite metal oxide and the catalyst metal particles were individually supported on carbon black, but MEA was prepared in the same manner as in Example 1, and the MEA was assembled into the cell to evaluate the performance.
- a catalyst ink of 0.0% by mass, Pt (5% by mass) / pyrochroma type Ce 2 Zr 2 O (20% by mass) / carbon black (95% by mass) was prepared.
- the above catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ). It was used as an electrode film.
- Comparative Example 3 MEA was prepared in the same manner as in Comparative Example 1 except that it was treated with fluorine silane (0.1% by mass) / Pt (5% by mass) / carbon black (94.9% by mass). Was assembled into the cell and the performance was evaluated.
- the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 150 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.8 ⁇ ⁇ cm.
- a fluorosilane-treated (0.1% by mass) / Pt (5% by mass) / carbon black (94.9% by mass) catalyst ink was prepared.
- the catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ). It was used as an electrode film.
- thermocompression bonding (150) to a polymer solid electrolyte membrane (NafionNR211, t 25 ⁇ m). °C) to prepare MEA.
- MEA was assembled in the cell and the performance was evaluated.
- ECA test "Gas flow rate” Anode: H 2 200 NmL / min Cathode: N 2 200 ⁇ 0 NmL / min (N 2 nitrogen is blocked before measurement) "Humidification temperature” Anode dew point (relative humidity): 80 ° C (RH100%) Cathode dew point (relative humidity): 80 ° C (RH100%) "Set pressure” Normal pressure "Cell temperature” 80 ° C "Measurement conditions” After nitrogen blocking, scanning is performed 5 times at 50 mV / sec between 0.05 V and 0.9 V.
- the fuel cell using the electrode in which the conductive composite metal oxide having a protrusion shape is supported on the surface of the catalyst-supporting conductor of the present invention is conductive, water-repellent, and / or absorbs and releases oxygen. It can be seen that the body is superior in power generation performance and durability performance as compared with Comparative Example 2 and Comparative Example 3 using an electrode made of a normal oxygen absorber or fluorine-based treatment. Furthermore, it can be seen that the amount of platinum used can be reduced if the core-shell type of the present invention is also used.
- Catalyst metal carrier 2 Conductive composite metal oxide having protrusions 3: Catalyst metal particles 4: Ionomer (polymer solid electrolyte) 5: Core layer 6: Shell layer
Abstract
A cathode for a polymer solid electrolyte fuel cell, wherein the effective utilization rate of platinum is improved as a result of a greater number of catalytic metal particles having reaction sites at which a catalyst, an ionomer and oxygen meet during catalysis, which are known as three-phase interfaces. Furthermore, even when overvoltage occurs as a result of the start/stop cycle and the travel load fluctuation cycle of a vehicle, it is possible to sustainably maintain the three-phase interface reaction sites. This cathode for a fuel cell has a catalyst layer comprising a catalyst support conductor and a polymer electrolyte, the surface of the catalyst support conductor is covered by a conductive complex metal oxide having projections, and the conductive complex metal oxide supports the catalytic metal particles.
Description
本発明は、燃料電池用カソード電極およびその製造方法、燃料電池用カソード電極を備えた固体高分子型燃料電池に関する。
The present invention relates to a cathode electrode for a fuel cell, a method for manufacturing the same, and a polymer electrolyte fuel cell provided with a cathode electrode for a fuel cell.
近年、燃料電池のなかでも、プロトン伝道による高分子電解質膜を有する固体高分子型燃料電池は、作動温度が低く、出力密度が高く、小型軽量化が容易であることから、究極の地球温暖化対策として自動車等の電源等としての普及が期待されている。しかしながら、従来の内燃機関のＰｔ使用量と比較して、５～１０倍のＰｔが必要であること、負荷走行サイクルおよび起動停止時サイクルの過電圧による、Ｐｔ溶出および高分子電解質の劣化が課題になっている。
In recent years, among fuel cells, polymer electrolyte fuel cells having a polymer electrolyte membrane by proton transmission have a low operating temperature, a high output density, and are easy to be compact and lightweight, resulting in ultimate global warming. As a countermeasure, it is expected to be widely used as a power source for automobiles and the like. However, there are problems that Pt is required 5 to 10 times as much as the amount of Pt used in the conventional internal combustion engine, and that Pt elution and deterioration of the polymer electrolyte due to overvoltage in the load running cycle and the start / stop cycle are problems. It has become.
高分子固体電解質燃料電池において、カソード電極の触媒表面では、酸素が還元され、カソード電極はアノード電極の触媒担持導電体から電子を受取り、水分子になる三相界面が形成されて連鎖的な反応が起きる。そのため、固体高分子型燃料電池においては、従来より、触媒担持導電体においては、比表面積を大きくして触媒活性点を増すこと、および触媒層を含フッ素イオン交換樹脂（以下、「アイオノマー」と言う場合がある）で被覆して電極とし、三相界面の形成が図られている。
In a polymer solid electrolyte fuel cell, oxygen is reduced on the catalyst surface of the cathode electrode, the cathode electrode receives electrons from the catalyst-supporting conductor of the anode electrode, and a three-phase interface that becomes water molecules is formed to form a chain reaction. Occurs. Therefore, in the polymer electrolyte fuel cell, conventionally, in the catalyst-supporting conductor, the specific surface area is increased to increase the catalytic activity point, and the catalyst layer is referred to as a fluorine ion exchange resin (hereinafter referred to as "ionomer"). It is coated with (sometimes referred to as) to form an electrode, and a three-phase interface is formed.
上記の触媒を被覆するアイオノマーとしては、プロトン導電性が高めるために、側鎖に強酸性のスルホン酸基を有するパーフルオロカーボン重合体が使用されている。
As the ionomer that coats the above catalyst, a perfluorocarbon polymer having a strongly acidic sulfonic acid group in the side chain is used in order to enhance proton conductivity.
しかし、従来のカソード電極の触媒層は、発電による電位が生じると、触媒とアイオノマーとの隙間が広がり、そこに水生する水分子が介在して、プロトン伝道が低下することが知られている（図３）。図３の（１）～（６）に記載のように、従来のカソード電極では、発電過負荷時に、生成した過酸化水素と過電圧とにより、表層の白金が酸化されると、アイオノマーが白金と乖離する。そこへ、生成水が溜まり、酸素がその生成水に溶存する。さらに、アイオノマーからスルホン酸基の腐食による脱離が起き、白金の酸化が進み生成水に溶出して表層の白金が減少する。反応サイトとしての三相界面が保たれなくなる。また、酸素の透過性が低下し、触媒層内の酸素透過性が不十分となり、カソード電極における酸素還元反応の過電圧が大きくなり、過酸化水素の分解による白金の酸化および溶出、高分子固体電解質のスルホン酸基含有パーフルオロカーボンからスルホン酸が解離することが知られている。
However, it is known that in the catalyst layer of the conventional cathode electrode, when a potential is generated by power generation, the gap between the catalyst and the ionomer widens, and aquatic water molecules intervene in the gap, and the proton transmission decreases ( Figure 3). As described in FIGS. 3 (1) to (6), in the conventional cathode electrode, when the platinum on the surface layer is oxidized by the generated hydrogen peroxide and the overvoltage during power generation overload, the ionomer becomes platinum. Dissociate. The produced water accumulates there, and oxygen dissolves in the produced water. Furthermore, desorption of sulfonic acid groups from ionomers occurs due to corrosion of sulfonic acid groups, and platinum is oxidized and eluted in the generated water to reduce the amount of platinum on the surface layer. The three-phase interface as a reaction site cannot be maintained. In addition, the permeability of oxygen decreases, the permeability of oxygen in the catalyst layer becomes insufficient, the overvoltage of the oxygen reduction reaction at the cathode electrode increases, the oxidation and elution of platinum due to the decomposition of hydrogen peroxide, and the polymer solid electrolyte. It is known that sulfonic acid is dissociated from perfluorocarbon containing a sulfonic acid group.
これに対して、下記特許文献１、２、３においては、触媒を被覆するフッ素樹脂またはフッ素系シランカップリング剤で処理した固体高分子形燃料電池および電極層が提案されている。
On the other hand, in Patent Documents 1, 2 and 3 below, a polymer electrolyte fuel cell and an electrode layer treated with a fluororesin or a fluorine-based silane coupling agent for coating a catalyst are proposed.
しかしながら、フッ素系樹脂およびフッ素系シランによる被覆処理では、自動車の走行負荷変動および起動停止に、フッ素樹脂の剥離およびシロキサン結合の加水分解が起き、耐久性の観点で十分でなかった。
However, the coating treatment with a fluororesin and a fluorosilane was not sufficient from the viewpoint of durability because the fluororesin was peeled off and the siloxane bond was hydrolyzed due to the fluctuation of the traveling load of the automobile and the start / stop.
一方、カソード電極層の酸素透過性に関して、において、触媒担持導電体の表面に、酸素吸放出のパイロクロア構造のＣｅ２Ｚｒ２Ｏ酸化物が、重なり合うことなく、個々に分かれて担持された方法が、下記特許文献４に開示されている。
On the other hand, regarding the oxygen permeability of the cathode electrode layer, there is a method in which Ce 2 Zr 2 O oxide having a pyrochlore structure for absorbing and releasing oxygen is individually supported on the surface of the catalyst-supporting conductor without overlapping. , Disclosed in Patent Document 4 below.
しかしながら、特許文献４に記載の固体高分子形燃料電池であっても、Ｃｅ２Ｚｒ２Ｏ酸化物は電子導電性が不十分であり、三相界面が生成できずカソード電極の内部抵抗が増加する。さらに、触媒と酸素吸放出のＣｅ２Ｚｒ２Ｏ酸化物が、重なり合うことがないことで、触媒金属粒子表面への酸素の到達が少なく、三相界面の形成が不十分であった。
However, even in the polymer electrolyte fuel cell described in Patent Document 4, the electron conductivity of Ce 2 Zr 2 O oxide is insufficient, a three-phase interface cannot be formed, and the internal resistance of the cathode electrode increases. To do. Further, since the catalyst and the Ce 2 Zr 2 O oxide for absorbing and releasing oxygen do not overlap with each other, oxygen does not reach the surface of the catalyst metal particles less, and the formation of the three-phase interface is insufficient.
本発明は、高分子固体電解質燃料電池のカソード電極において、触媒作用時に、三相界面と呼ばれる触媒、アイオノマーおよび酸素（言い換えれば、触媒金属粒子の表面で水素イオン、酸素、および電子と）が会合する反応サイトを、より多くの触媒金属粒子で有し、白金有効利用率を向上させることにある。さらに、自動車の走行負荷変動サイクルおよび起動停止サイクルの過電圧がともなっても、持続的に三相界面の反応サイトの保持を可能にすることにある。
In the present invention, in the cathode electrode of a polymer solid electrolyte fuel cell, a catalyst called a three-phase interface, ionomer and oxygen (in other words, hydrogen ions, oxygen, and electrons are associated with each other on the surface of the catalyst metal particles) are associated with each other during catalysis. The purpose is to have more catalytic metal particles to have a reaction site to improve the effective utilization rate of platinum. Furthermore, it is to enable the continuous retention of the reaction site at the three-phase interface even in the presence of overvoltages in the traveling load fluctuation cycle and the start / stop cycle of the automobile.
特許文献１、２および３のように、フッ素樹脂またはフッ素系シランを触媒担持カーボンに被覆処理して撥水性を付与すると、自動車の走行負荷変動および起動停止によって、フッ素樹脂の剥離およびシロキサン結合の加水分解が起き、触媒とアイオノマーとの界面に隙間が生じ水素イオン伝道が低下する。さらに、その隙間に水分が溜まり、酸素がその水分に溶存して酸素の供給が低下する。したがって、三相界面の反応サイトへの水素イオンおよび酸素の会合が減少し、発電性能が低下することが問題であった。
As in Patent Documents 1, 2 and 3, when a fluororesin or a fluorosilane is coated on a catalyst-supported carbon to impart water repellency, the fluororesin is peeled off and a siloxane bond is formed due to fluctuations in the traveling load of the automobile and start / stop. Hydrolysis occurs, creating a gap at the interface between the catalyst and the ionomer, reducing hydrogen ion transmission. Further, water is accumulated in the gap, oxygen is dissolved in the water, and the supply of oxygen is reduced. Therefore, there is a problem that the association of hydrogen ions and oxygen to the reaction site at the three-phase interface is reduced and the power generation performance is lowered.
一方、特許文献４のように、パイロクロア型Ｃｅ２Ｚｒ２Ｏ７からなる酸素吸放出体が、触媒担持導電体の表面に、触媒金属粒子と直接的に接することなく別々に存在する場合は、酸素が生成水に溶存しやすく、触媒金属粒子表面での三相界面の反応サイトへの供給が低下する。さらに、前記パイロクロア型Ｃｅ２Ｚｒ２Ｏ７からなる酸素吸放出体は、電子電導性が低いために、カソード電極の内部抵抗が増し、自動車の走行負荷変動サイクルおよび起動停止サイクルの過電圧が高くなり、白金の酸化、および溶出、アイオノマーのスルホン酸基の分解および触媒担持導電体（導電性カーボン）の腐食につながる。
On the other hand, as in Patent Document 4, when the oxygen absorber composed of the pyrochlor type Ce 2 Zr 2 O 7 is separately present on the surface of the catalyst-supporting conductor without being in direct contact with the catalyst metal particles, Oxygen is easily dissolved in the generated water, and the supply to the reaction site at the three-phase interface on the surface of the catalyst metal particles is reduced. Further, since the oxygen absorber made of the pyrochloro type Ce 2 Zr 2 O 7 has low electron conductivity, the internal resistance of the cathode electrode increases, and the overvoltage of the traveling load fluctuation cycle and the start / stop cycle of the automobile becomes high. , Oxidation and elution of platinum, decomposition of sulfonic acid groups of ionomer and corrosion of catalyst-bearing conductors (conductive carbon).
本発明者は、触媒金属粒子表面へ、水素イオンの伝導、電子の伝導および酸素が会合し、三相界面のサイトを、持続的に形成できるよう、突起状を有する金属酸化物が、触媒金属粒子と触媒担持導電体との間にあって直接的に接し、撥水性、電子電導性および酸素吸放出性を有することにより、上記課題が解決することを見出し本発明に至った。
In the present invention, the metal oxide having protrusions is a catalyst metal so that the conduction of hydrogen ions, the conduction of electrons and oxygen can be associated with the surface of the catalyst metal particles to continuously form the site of the three-phase interface. We have found that the above problems can be solved by having direct contact between the particles and the catalyst-supporting conductor and having water repellency, electron conductivity and oxygen absorption / release property, and have reached the present invention.
上記課題を解決するために、本発明の燃料電池用カソード電極は、触媒担持導電体と、高分子電解質とからなる触媒層を有し、前記触媒担持導電体の表面が、突起を有する導電性複合金属酸化物で覆われ、前記導電性複合金属酸化物に、触媒金属粒子が担持されている。
In order to solve the above problems, the cathode electrode for a fuel cell of the present invention has a catalyst layer composed of a catalyst-supporting conductor and a polymer electrolyte, and the surface of the catalyst-supporting conductor has protrusions. It is covered with a composite metal oxide, and catalyst metal particles are supported on the conductive composite metal oxide.
前記導電性複合金属酸化物の前記突起の高さが、５ｎｍ～１５ｎｍであってもよい。
The height of the protrusions of the conductive composite metal oxide may be 5 nm to 15 nm.
前記導電性複合金属酸化物が、水との接触角で１４０度以上の撥水性を有してもよい。
The conductive composite metal oxide may have a water repellency of 140 degrees or more at a contact angle with water.
前記触媒担持導電体が、０．２Ω・ｃｍ以下の比抵抗を有してもよい。
The catalyst-supported conductor may have a specific resistance of 0.2 Ω · cm or less.
前記導電性複合金属酸化物が、酸素吸放出体であってもよい。
The conductive composite metal oxide may be an oxygen absorber.
前記導電性複合金属酸化物が、ｐ型半導体であってもよい。
The conductive composite metal oxide may be a p-type semiconductor.
前記導電性複合金属酸化物が、Ｓｎ2Ｍ2Ｏ７（Ｍ＝Ｔａおよび／またはＮｂ）からなるパイロクロア構造を有してもよい。
The conductive composite metal oxide may have a pyrochlore structure composed of Sn 2 M 2 O 7 (M = Ta and / or Nb).
前記導電性複合金属酸化物が、ＴａドープＳｎＯ2（０．０１質量％≦Ｔａ≦１．０質量％）を含んでもよい。
The conductive composite metal oxide may contain Ta-doped SnO 2 (0.01% by mass ≤ Ta ≤ 1.0% by mass).
前記触媒金属粒子が、Ｐｔのシェル層からなるコアシェル構造を有してもよい。
The catalyst metal particles may have a core-shell structure composed of a Pt shell layer.
前記コアシェル構造のコア層が、Ｐｄと、Ｐｔ、ＲｕおよびＣｏの少なくとも一つから選ばれてなる合金からなるものであってもよい。
The core layer of the core-shell structure may be made of Pd and an alloy selected from at least one of Pt, Ru and Co.
前記触媒担持導電体が、導電性カーボン、グラファイト、グラフェンおよびカーボンアロイから選ばれる少なくとも一つからなるものであってもよい。
The catalyst-supporting conductor may consist of at least one selected from conductive carbon, graphite, graphene and carbon alloy.
また、上記課題を解決するために、本発明の燃料電池用カソード電極の製造方法は、上記した本発明の燃料電池用カソード電極の製造方法であって、前記触媒担持導電体の懸濁液に、塩化スズ（II）および塩化タンタル（V）を加え、ｐＨ１．５～２．０に制御して前記導電性複合金属酸化物を得る工程を含む。
Further, in order to solve the above-mentioned problems, the method for manufacturing a cathode electrode for a fuel cell of the present invention is the above-mentioned method for manufacturing a cathode electrode for a fuel cell of the present invention, and the suspension of the catalyst-supporting conductor , Tin chloride (II) and tantalum chloride (V) are added, and the pH is controlled to 1.5 to 2.0 to obtain the conductive composite metal oxide.
前記導電性複合金属酸化物で被覆された前記触媒担持導電体の懸濁液に、コア層を構成する金属塩を加えたものを、４０℃～８０℃に加温して還元する第１還元工程を含み、前記第１還元工程により、前記触媒担持導電体の表面を被覆する突起状の前記導電性複合金属酸化物の表面に、前記触媒金属粒子のコア層が形成されてもよい。
A first reduction in which a suspension of the catalyst-supporting conductor coated with the conductive composite metal oxide, to which a metal salt constituting the core layer is added, is heated to 40 ° C. to 80 ° C. and reduced. The core layer of the catalyst metal particles may be formed on the surface of the protruding conductive composite metal oxide that covers the surface of the catalyst-supporting conductor by the first reduction step.
突起状の前記導電性複合金属酸化物の表面に、前記触媒金属粒子の前記コア層を有する前記触媒担持導電体の懸濁液に、Ｐｔ塩溶液と還元剤とを加えて還元する第２還元工程を含み、前記第２還元工程により、前記触媒金属粒子のＰｔシェル層が形成されてもよい。
A second reduction in which a Pt salt solution and a reducing agent are added to a suspension of the catalyst-supporting conductor having the core layer of the catalyst metal particles on the surface of the projecting conductive composite metal oxide. Including the step, the Pt shell layer of the catalyst metal particles may be formed by the second reduction step.
また、上記課題を解決するために、本発明の固体高分子型燃料電池は、アノード電極と、上記した本発明のカソード電極と、前記アノード電極と前記カソード電極との間に配置された高分子電解質膜と、を有する。
Further, in order to solve the above problems, the polymer electrolyte fuel cell of the present invention has a polymer arranged between the anode electrode, the cathode electrode of the present invention, and the anode electrode and the cathode electrode. It has an electrolyte membrane.
前記導電性複合金属酸化物が、Ｓｎ2Ｍ2Ｏ７（Ｍ＝Ｔａおよび／またはＮｂ）からなるパイロクロア構造を有してもよい。
The conductive composite metal oxide may have a pyrochlore structure composed of Sn 2 M 2 O 7 (M = Ta and / or Nb).
前記導電性複合金属酸化物が、ＴａドープＳｎＯ2（０．０１質量％≦Ｔａ≦１．０質量％）を含んでもよい。
The conductive composite metal oxide may contain Ta-doped SnO 2 (0.01% by mass ≤ Ta ≤ 1.0% by mass).
本発明によれば、燃料電池用カソード電極において、突起状を有するパイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７ の結晶からなる複合金属酸化物が持続性のある撥水性を有し、さらに電子電導性および酸素吸放出性、もしくは、酸素吸放出体ではないＴａドープＳｎＯ2 とから、触媒金属粒子表面に三相界面の反応サイトを高度に実現した酸素還元反応により、高い発電性能を得ることができた。
According to the present invention, in the cathode electrode for a fuel cell, a composite metal oxide composed of a pyrochloro-type Sn 2 Ta 2 O 7 having a protrusion and / or a crystal of Sn 2 Nb 2 O 7 has a long-lasting water repellency. By the oxygen reduction reaction that highly realizes the reaction site of the three-phase interface on the surface of the catalyst metal particles from Ta-doped SnO 2 , which is electron-conducting and oxygen-absorbing / releasing, or is not an oxygen-absorbing / releasing substance. High power generation performance could be obtained.
以下、本発明のカソード電極およびこれを備えた固体高分子型燃料電池の好適な実施形態について詳細に説明する。
Hereinafter, a preferred embodiment of the cathode electrode of the present invention and the polymer electrolyte fuel cell provided with the cathode electrode will be described in detail.
本発明は、前記三相界面の反応サイトを確保するために、以下の（１）～（３）の３つの要素が成り立つことが好ましい。
In the present invention, in order to secure the reaction site at the three-phase interface, it is preferable that the following three elements (1) to (3) are satisfied.
（１）本発明は、触媒担持導電体の表面に、５ｎｍ～１５ｎｍの突起状を有する複合金属酸化物を形成することで、アイオノマーとの濡れがよくて白金有効率が高く、水分を排出でき、かつ触媒作動時に触媒とアイオノマーとが密着できる、持続的な撥水性を保持できることにある。
（２）本発明は、前記複合金属酸化物がパイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７ の結晶構造 からなる酸素吸放出性を有し、触媒金属粒子が前記金属酸化物の表面に接していて、酸素が生成する水分に溶存することなく、触媒金属粒子へ効率が高い供給を可能にすることにある。
（３）本発明は、パイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７の結晶構造からなる酸素吸放出性を有する前記複合金属酸化物が、触媒担持導電体と触媒金属粒子との間に接して設けられ、電子電導性を有することで、触媒金属粒子表面での三相界面の反応サイトへ、電子を供給することを可能にすることにある。同時に、金属酸化物が触媒担持導電体の腐食を防ぐことができる。 (1) In the present invention, by forming a composite metal oxide having protrusions of 5 nm to 15 nm on the surface of the catalyst-supported conductor, the wettability with ionomer is good, the platinum effectiveness rate is high, and water can be discharged. In addition, the catalyst and the ionomer can be brought into close contact with each other when the catalyst is operated, and the continuous water repellency can be maintained.
(2) In the present invention, the composite metal oxide has a crystal structure of pyrochlore type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 . The catalyst metal particles are in contact with the surface of the metal oxide and are not dissolved in the water generated by oxygen, so that the catalyst metal particles can be efficiently supplied. is there.
(3) In the present invention, the composite metal oxide having an oxygen absorbing / releasing property having a crystal structure of pyrochlorotype Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 is a catalyst-supporting conductor and a catalyst metal. It is provided in contact with the particles and has electron conductivity, so that electrons can be supplied to the reaction site at the three-phase interface on the surface of the catalyst metal particles. At the same time, the metal oxide can prevent corrosion of the catalyst-supported conductor.
（２）本発明は、前記複合金属酸化物がパイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７ の結晶構造 からなる酸素吸放出性を有し、触媒金属粒子が前記金属酸化物の表面に接していて、酸素が生成する水分に溶存することなく、触媒金属粒子へ効率が高い供給を可能にすることにある。
（３）本発明は、パイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７の結晶構造からなる酸素吸放出性を有する前記複合金属酸化物が、触媒担持導電体と触媒金属粒子との間に接して設けられ、電子電導性を有することで、触媒金属粒子表面での三相界面の反応サイトへ、電子を供給することを可能にすることにある。同時に、金属酸化物が触媒担持導電体の腐食を防ぐことができる。 (1) In the present invention, by forming a composite metal oxide having protrusions of 5 nm to 15 nm on the surface of the catalyst-supported conductor, the wettability with ionomer is good, the platinum effectiveness rate is high, and water can be discharged. In addition, the catalyst and the ionomer can be brought into close contact with each other when the catalyst is operated, and the continuous water repellency can be maintained.
(2) In the present invention, the composite metal oxide has a crystal structure of pyrochlore type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 . The catalyst metal particles are in contact with the surface of the metal oxide and are not dissolved in the water generated by oxygen, so that the catalyst metal particles can be efficiently supplied. is there.
(3) In the present invention, the composite metal oxide having an oxygen absorbing / releasing property having a crystal structure of pyrochlorotype Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 is a catalyst-supporting conductor and a catalyst metal. It is provided in contact with the particles and has electron conductivity, so that electrons can be supplied to the reaction site at the three-phase interface on the surface of the catalyst metal particles. At the same time, the metal oxide can prevent corrosion of the catalyst-supported conductor.
即ち、第１に、本発明は、触媒担持導電体と、アイオノマーとからなる触媒層を有する燃料電池用カソード電極の発明であって、触媒担持導電体の表面に、突起状のパイロクロア型Ｓｎ２Ｔａ２Ｏ７、Ｓｎ２Ｎｂ２Ｏ７および／またはＴａドープＳｎＯ2の結晶構造の導電性複合金属酸化物が形成され、さらに導電性複合金属酸化物の表面に触媒金属粒子が担持されていることが好ましい。
That is, first, the present invention is an invention of a cathode electrode for a fuel cell having a catalyst layer composed of a catalyst-supporting conductor and an ionomer, and is a pyrochloro-type Sn 2 having a protrusion on the surface of the catalyst-supporting conductor. Ta 2 O 7, Sn 2 Nb 2 O 7 and / or conductive composite metal oxide of the crystal structure of Ta-doped SnO 2 are formed, the catalyst metal particles are supported on the surface of the further conductive complex metal oxides Is preferable.
本発明のカソード電極は、触媒担持導電体の表面に微細な突起状のパイロクロア型Ｓｎ２Ｔａ２Ｏ７、Ｓｎ２Ｎｂ２Ｏ７および／またはＴａドープＳｎＯ2の結晶構造からなる導電性複合金属酸化物がさらに担持されている場合には、その突起形成により持続性のある撥水性を有し、導電性複合金属酸化物の表面に触媒金属粒子が担持されているので、触媒金属粒子へ導電性複合金属酸化物の酸素欠陥により電子を電導させ、さらに、前記パイロクロア型Ｓｎ２Ｔａ２Ｏ７、Ｓｎ２Ｎｂ２Ｏ７および／またはＴａドープＳｎＯ2の結晶構造の酸素欠陥により酸素キャリアが、直接的に触媒金属粒子へ酸素分子の拡散経路が確保される。
The cathode electrode of the present invention, the conductive composite metal comprising a crystal structure of the catalyst carrier conductive pyrochlore type surface fine protruding Sn 2 Ta 2 O 7, Sn 2 Nb 2 O 7 and / or Ta-doped SnO 2 When the oxide is further supported, it has long-lasting water repellency due to the formation of protrusions, and since the catalyst metal particles are supported on the surface of the conductive composite metal oxide, it is conductive to the catalyst metal particles. The oxygen defect of the sex composite metal oxide conducts electrons, and the oxygen carrier of the crystal structure of the pyrochloro type Sn 2 Ta 2 O 7 , Sn 2 Nb 2 O 7 and / or Ta-doped Sn O 2 causes oxygen carriers. A diffusion path for oxygen molecules is secured directly to the catalytic metal particles.
その結果、持続性の撥水性で水素イオンの伝導、パイロクロア型Ｓｎ２Ｔａ２Ｏ７、Ｓｎ２Ｎｂ２Ｏ７および／またはＴａドープＳｎＯ2の結晶構造の電子伝導性および酸素キャリア性により、電子および酸素分子を触媒金属粒子の表面に会合を確保して、電極反応における交換電流密度を増大させることができ過電圧を低減できる。すなわち、高い電極特性を得ることができる。特に、固体高分子型燃料電池のカソード電極として使用すれば、カソード電極の酸素還元反応の過電圧を効果的に低減させることができるので、カソード電極の電極特性を向上させることができる。酸素ガスの不足は、特に、燃料電池が運転中に生じるが、本発明により、長時間の運転中も高い電極特性を維持することが出来る。
As a result, due to the persistent water repellency and conduction of hydrogen ions, the electron conductivity and oxygen carrier properties of the crystal structure of pyrochloro-type Sn 2 Ta 2 O 7 , Sn 2 Nb 2 O 7 and / or Ta-doped Sn O 2 , electrons And oxygen molecules can be associated with the surface of the catalytic metal particles to increase the exchange current density in the electrode reaction and reduce overvoltage. That is, high electrode characteristics can be obtained. In particular, when it is used as a cathode electrode of a polymer electrolyte fuel cell, the overvoltage of the oxygen reduction reaction of the cathode electrode can be effectively reduced, so that the electrode characteristics of the cathode electrode can be improved. The shortage of oxygen gas occurs especially during operation of the fuel cell, but according to the present invention, high electrode characteristics can be maintained even during long-term operation.
本発明は、２０ｎｍ～５０ｎｍの粒子径からなる触媒担体導電体の表面に、導電性複合金属酸化物からなる５ｎｍ～１５ｎｍの高さと間隔を有する突起を形成し、過電圧および過酸化水素による腐食に耐えうる持続性のある撥水性の維持を可能にした。
In the present invention, protrusions made of a conductive composite metal oxide having a height and an interval of 5 nm to 15 nm are formed on the surface of a catalyst carrier conductor having a particle size of 20 nm to 50 nm, and are resistant to corrosion by overvoltage and hydrogen peroxide. It made it possible to maintain durable water repellency that can be tolerated.
本発明の導電性複合金属酸化物が、パイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７ の結晶構造を有する場合には、酸素欠陥により正孔を生成し、Ｐ型半導体特性を有し電子導電性を可能にした。
When the conductive composite metal oxide of the present invention has a pyrochlore-type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 crystal structure, holes are generated by oxygen defects and a P-type semiconductor is generated. It has characteristics and enables electron conductivity.
さらに、本発明で用いることのできるパイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７の結晶は、近傍の酸素濃度の変動によって、その結晶の酸素欠陥により酸素の吸収と放出を可逆的に繰り返すことができる機能を有する酸素キャリア材の１種である。即ち、比較的Ｏ２濃度が高い時に酸素を吸収し、Ｏ２濃度が低い雰囲気下で酸素を放出するこができる。
Furthermore, the pyrochlore-type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 crystals that can be used in the present invention absorb and release oxygen due to oxygen defects in the crystals due to fluctuations in oxygen concentration in the vicinity. Is one of the oxygen carrier materials having a function of being able to reversibly repeat. That is, oxygen can be absorbed when the O 2 concentration is relatively high, and oxygen can be released in an atmosphere where the O 2 concentration is low.
本発明においては、表面にパイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７ が担持される触媒担持導電体として、多孔質カーボン粉末、グラファイト粉末またはグラフェン粉末であることが好ましい。
In the present invention, the catalyst-supported conductor in which the pyrochlore-type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 is supported on the surface is preferably porous carbon powder, graphite powder or graphene powder. ..
また、第２に、固体高分子型燃料電池の発明であって、カソード電極は、触媒担持導電体と、アイオノマーとからなる触媒層を有し、触媒担持導電体の表面には、パイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７からなる酸素吸放出体、もしくは、酸素吸放出体ではないＴａドープＳｎＯ2と、その表面に触媒金属粒子さらに担持されていることが好ましい。
Secondly, in the invention of the polymer electrolyte fuel cell, the cathode electrode has a catalyst layer composed of a catalyst-supporting conductor and an ionomer, and the surface of the catalyst-supporting conductor has a pyrochlor-type Sn. It is preferable that an oxygen absorber composed of 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 , or Ta-doped SnO 2 which is not an oxygen absorber, and catalyst metal particles are further supported on the surface thereof. ..
このように、先に述べた酸素還元反応に対する優れた電極特性を有する本発明のカソード電極を備えることにより、高い電池出力を有する固体高分子型燃料電池を構成することが可能となる。また、先に述べたように、本発明のカソード電極は、自動車の走行負荷変動サイクルおよび起動停止サイクルの過電圧が高くなり、白金の酸化、および溶出、アイオノマーのスルホン酸基の分解および触媒担持導電体（導電性カーボン）の腐食を防止することができるとともに、耐久性に優れているので、これを備える本発明の固体高分子型燃料電池は高い電池出力を長期にわたり安定して得ることが可能となる。
As described above, by providing the cathode electrode of the present invention having excellent electrode characteristics for the oxygen reduction reaction described above, it is possible to construct a polymer electrolyte fuel cell having a high battery output. Further, as described above, in the cathode electrode of the present invention, the overvoltage of the traveling load fluctuation cycle and the start / stop cycle of the automobile becomes high, platinum oxidation and elution, decomposition of the sulfonic acid group of the ionomer, and catalyst-supported conductivity. Since the body (conductive carbon) can be prevented from corroding and has excellent durability, the polymer electrolyte fuel cell of the present invention provided with this can stably obtain a high battery output for a long period of time. It becomes.
図１が示すとおり、触媒担体導電体の表面に、微細な突起状を有する複合金属酸化物が被覆されている。その複合金属酸化物の表面に、触媒金属粒子が担持されている。このようにして複合された粒子は、その突起状がスペーサーの役割を果たし、アイオノマーが突起状の頂点まで均一な厚みで覆っている。
As shown in FIG. 1, the surface of the catalyst carrier conductor is coated with a composite metal oxide having fine protrusions. Catalytic metal particles are supported on the surface of the composite metal oxide. In the particles composited in this way, the protrusions act as spacers, and the ionomer covers the tops of the protrusions with a uniform thickness.
図２が示すとおり、まず、水素イオンが、アイオノマー中を伝導して触媒金属粒子表面へ移動する。次に、電子は、触媒担体導電体から導電性を有する複合金属酸化物を通り、触媒金属粒子表面へ移動する。さらに、酸素分子は、前記複合酸化物に貯蔵された酸素が触媒金属粒子表面に移動する。このようにして、本発明のカソード電極は、触媒金属粒子表面で三相界面の反応サイトが成立し、酸素還元反応が進行する。この酸素還元反応を［化１］に示す。
As shown in FIG. 2, first, hydrogen ions are conducted through the ionomer and move to the surface of the catalyst metal particles. Next, the electrons move from the catalyst carrier conductor through the conductive composite metal oxide to the surface of the catalyst metal particles. Further, in the oxygen molecule, oxygen stored in the composite oxide moves to the surface of the catalyst metal particles. In this way, in the cathode electrode of the present invention, a reaction site at the three-phase interface is established on the surface of the catalytic metal particles, and the oxygen reduction reaction proceeds. This oxygen reduction reaction is shown in [Chemical formula 1].
［化１］
Ｏ２ ＋ ４Ｈ＋ ＋ ４ｅ－ → ２Ｈ２Ｏ [Chemical 1]
O 2 + 4H + + 4e - → 2H 2 O
Ｏ２ ＋ ４Ｈ＋ ＋ ４ｅ－ → ２Ｈ２Ｏ [Chemical 1]
O 2 + 4H + + 4e - → 2H 2 O
本発明は、触媒担持導電体の表面に、突起状を有するパイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７ の導電性複合金属酸化物が担持される。この微細な突起状が、持続的な撥水性を有することにより、高出力時であっても触媒とアイオノマーとが密着を保持でき、多くの水素イオンが触媒金属粒子へ到達できる。
In the present invention, a pyrochlore-type Sn 2 Ta 2 O 7 and / or a Sn 2 Nb 2 O 7 conductive composite metal oxide having protrusions is supported on the surface of the catalyst-supporting conductor. Since the fine protrusions have continuous water repellency, the catalyst and the ionomer can maintain close contact even at high output, and many hydrogen ions can reach the catalyst metal particles.
酸素は、燃料電池が低出力時において、触媒での酸素消費量が少なく、酸素吸放出体近傍の酸素濃度が濃いため酸素吸放出体に余剰の酸素が吸蔵される。一方、触媒での酸素消費量が多く酸素吸放出体近傍の酸素濃度が薄くなるため、前記複合金属酸化物から触媒金属粒子へ酸素が直接的に移動されるため、触媒層のガス拡散の影響を受けることなく、生成水に酸素が溶存され酸素が消費されることなく、酸素が触媒上で還元されることにより、燃料電池性能が更に向上する。
As for oxygen, when the fuel cell has a low output, the amount of oxygen consumed by the catalyst is small, and the oxygen concentration near the oxygen absorber is high, so excess oxygen is stored in the oxygen absorber. On the other hand, since the amount of oxygen consumed by the catalyst is large and the oxygen concentration in the vicinity of the oxygen absorber is low, oxygen is directly transferred from the composite metal oxide to the catalyst metal particles, so that the influence of gas diffusion in the catalyst layer The performance of the fuel cell is further improved by reducing oxygen on the catalyst without receiving oxygen in the generated water and consuming oxygen.
電極反応は三相界面と呼ばれる反応ガス、触媒、電解質が会合するサイトにて進行する。三相界面への酸素の供給が一つの重要なトピックとしてある。電池の出力を高くした場合、反応に大量の酸素が必要となり、触媒近傍に酸素がなければ発電特性は急激に低下する。従来の技術では高濃度の酸素を供給するという形式であるが、図１に示すように、実際の反応は三相界面（触媒近傍）で行われるので、ここに酸素が供給されていなければその能力を十二分に発揮させることができない。特に、出力をあげた場合、触媒表面での酸素消費量は上昇するが、外部から触媒表面に至る酸素の拡散速度は殆ど変化することがない。その為、ある一定以上の触媒表面での酸素の消費速度が、触媒表面への酸素の供給速度を上回った場合、触媒近傍付近の酸素欠により発電特性は低下する。これに対して、図２に示すように、本発明では、触媒表面への酸素の供給速度を高めることによって、触媒近傍付近の酸素欠による発電特性の低下を防止している。
The electrode reaction proceeds at the site where the reaction gas, catalyst, and electrolyte meet, which is called the three-phase interface. The supply of oxygen to the three-phase interface is one important topic. When the output of the battery is increased, a large amount of oxygen is required for the reaction, and if there is no oxygen in the vicinity of the catalyst, the power generation characteristics deteriorate sharply. In the conventional technique, a high concentration of oxygen is supplied, but as shown in FIG. 1, the actual reaction is carried out at the three-phase interface (near the catalyst), so if oxygen is not supplied here, it will be the same. I can't fully demonstrate my abilities. In particular, when the output is increased, the oxygen consumption on the catalyst surface increases, but the diffusion rate of oxygen from the outside to the catalyst surface hardly changes. Therefore, when the oxygen consumption rate on the catalyst surface above a certain level exceeds the oxygen supply rate to the catalyst surface, the power generation characteristics deteriorate due to lack of oxygen in the vicinity of the catalyst. On the other hand, as shown in FIG. 2, in the present invention, by increasing the supply rate of oxygen to the catalyst surface, deterioration of power generation characteristics due to lack of oxygen in the vicinity of the catalyst is prevented.
本発明の固体高分子型燃料電池のカソード電極は、触媒層を備えるが、触媒層と、該触媒層に隣接して配置されるガス拡散層とからなることが好ましい。ガス拡散層の構成材料としては、例えば、電子伝導性を有する多孔質体（例えば、カーボンクロスやカーボンペーパー）が使用される。
The cathode electrode of the polymer electrolyte fuel cell of the present invention includes a catalyst layer, and is preferably composed of a catalyst layer and a gas diffusion layer arranged adjacent to the catalyst layer. As a constituent material of the gas diffusion layer, for example, a porous body having electron conductivity (for example, carbon cloth or carbon paper) is used.
カソード電極の触媒層には、突起状による撥水性と、導電性および酸素吸放出性を有するパイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７が存在しており、カソード電極における酸素還元反応に対する過電圧を低減させることによるカソード電極の電極反応速度の向上が図られる。一方、酸素吸放出性を有さないＴａドープＳｎＯ２複合金属酸化物においても、カソード電極における酸素還元反応に対する過電圧を低減させることによるカソード電極の電極反応速度の向上が図られる。
In the catalyst layer of the cathode electrode, a pyrochlor type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 having water repellency due to protrusions and conductivity and oxygen absorption / release property are present, and the cathode electrode The electrode reaction rate of the cathode electrode is improved by reducing the overvoltage with respect to the oxygen reduction reaction in the above. On the other hand, even in the Ta-doped SnO 2 composite metal oxide having no oxygen absorption / release property, the electrode reaction rate of the cathode electrode can be improved by reducing the overvoltage with respect to the oxygen reduction reaction in the cathode electrode.
また、触媒層に含まれている、パイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７複合金属酸化物の含有率は触媒担持導電体と高分子電解質と触媒金属粒子の合量に対して、０．０１～３０質量％であることが好ましく、０．０１～２０質量％であることがより好ましい。ここで、パイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７の含有率が０．０１質量％未満であると、撥水性、電子電導性および酸素吸放出性の低下し、アイオノマーと触媒金属粒子の乖離、生成水へ酸素の溶存、触媒金属の酸化と溶出、アイオノマーのスルホン酸基の分解および触媒担持導電体の腐食が起こり十分な酸素還元反応が行えず、持続的な発電することが困難となる傾向が大きくなる。一方、パイロクロア型Ｓｎ２Ｔａ２Ｏ７、および／またはＳｎ２Ｎｂ２Ｏ７ 複合金属酸化物の含有率が３０質量％を超えると触媒層中に含有されるアイオノマーの含有率が相対的に低下し、その結果、触媒層中で有効に機能する反応サイトが減少するため高い電極特性を得ることが困難となる。
The content of the pyrochlore-type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 composite metal oxide contained in the catalyst layer is the combination of the catalyst-supported conductor, the polymer electrolyte, and the catalyst metal particles. The amount is preferably 0.01 to 30% by mass, more preferably 0.01 to 20% by mass, based on the amount. Here, when the content of the pyrochlor type Sn 2 Ta 2 O 7 and / or Sn 2 Nb 2 O 7 is less than 0.01% by mass, the water repellency, the electron conductivity and the oxygen absorption / release property are lowered. Dissociation between the ionomer and the catalyst metal particles, dissolution of oxygen in the generated water, oxidation and elution of the catalyst metal, decomposition of the sulfonic acid group of the ionomer, and corrosion of the catalyst-supporting conductor, resulting in insufficient oxygen reduction reaction, which is persistent. The tendency for it to become difficult to generate electricity increases. On the other hand, when the content of the pyrochlore-type Sn 2 Ta 2 O 7 and / or the Sn 2 Nb 2 O 7 composite metal oxide exceeds 30% by mass, the content of ionomer contained in the catalyst layer decreases relatively. As a result, it becomes difficult to obtain high electrode characteristics because the number of reaction sites that function effectively in the catalyst layer is reduced.
一方、触媒層に含まれている、ＴａドープＳｎＯ２複合金属酸化物の含有率は触媒担持導電体と高分子電解質と触媒金属粒子の合量に対して、０．０１～３０質量％であることが好ましく、０．０１～２０質量％であることがより好ましい。ＴａドープＳｎＯ２の含有率が０．０１質量％未満であると、撥水性、電子電導性および酸素吸放出性の低下し、アイオノマーと触媒金属粒子の乖離、生成水へ酸素の溶存、触媒金属の酸化と溶出、アイオノマーのスルホン酸基の分解および触媒担持導電体の腐食が起こり十分な酸素還元反応が行えず、持続的な発電することが困難となる傾向が大きくなる。また、ＴａドープＳｎＯ２複合金属酸化物の含有率が３０質量％を超えると触媒層中に含有されるアイオノマーの含有率が相対的に低下し、その結果、触媒層中で有効に機能する反応サイトが減少するため高い電極特性を得ることが困難となる。
On the other hand, the content of the Ta-doped SnO 2 composite metal oxide contained in the catalyst layer is 0.01 to 30% by mass with respect to the total amount of the catalyst-supporting conductor, the polymer electrolyte, and the catalyst metal particles. It is preferably 0.01 to 20% by mass, and more preferably 0.01 to 20% by mass. When the content of Ta-doped SnO 2 is less than 0.01% by mass, the water repellency, electron conductivity and oxygen absorption / release property are lowered, the ionomer and the catalyst metal particles are separated, oxygen is dissolved in the produced water, and the catalyst metal is dissolved. Oxidation and elution, decomposition of the sulfonic acid group of the ionomer, and corrosion of the catalyst-supporting conductor occur, and a sufficient oxygen reduction reaction cannot be performed, which increases the tendency that continuous power generation becomes difficult. Further, when the content of the Ta-doped SnO 2 composite metal oxide exceeds 30% by mass, the content of ionomer contained in the catalyst layer is relatively reduced, and as a result, a reaction that functions effectively in the catalyst layer. Since the number of sites is reduced, it becomes difficult to obtain high electrode characteristics.
前記ＴａドープＳｎＯ２は、ＳｎＯ２中にＴａの含有率が０．１～１０質量％が好ましく、さらに０．５～５．０質量％であることがより好ましい。Ｔａの含有率が０．１質量％未満であると、触媒金属へ電子の三相界面の会合が減少して発電力が低下する。
The Ta-doped SnO 2 preferably has a Ta content of 0.1 to 10% by mass, more preferably 0.5 to 5.0% by mass in SnO 2 . When the Ta content is less than 0.1% by mass, the association of electrons with the catalyst metal at the three-phase interface is reduced, resulting in a decrease in power generation.
本発明のカソード電極の触媒担持導電体に含まれる触媒は特に限定されるものではないが、白金、白金合金またはコアシェル型（例えば、図４に示すコア層５を囲むシェル層６が白金、コア層５がＰｄ、Ｐｔ、Ｒｕおよび／またはＣｏから選ばれる合金）が好ましい。更に、触媒担持導電体は、特に限定されないが、比表面積が２００ｍ２／ｇ以上のカーボン材料が好ましい。例えば、カーボンブラック、グラファイトまたはグラフェンなどが好ましく使用される。
The catalyst contained in the catalyst-supporting conductor of the cathode electrode of the present invention is not particularly limited, but platinum, platinum alloy or core-shell type (for example, the shell layer 6 surrounding the core layer 5 shown in FIG. 4 is platinum, core. Layer 5 is preferably an alloy selected from Pd, Pt, Ru and / or Co). Further, the catalyst-supported conductor is not particularly limited, but a carbon material having a specific surface area of 200 m 2 / g or more is preferable. For example, carbon black, graphite or graphene is preferably used.
また、本発明の触媒層に含有されるアイオノマーとしては、含フッ素イオン交換樹脂が好ましく，特に、スルホン酸型パーフルオロカーボン重合体であることが好ましい。スルホン酸型パーフルオロカーボン重合体は、カソード電極内において長期間化学的に安定でかつ速やかな水素イオン伝導を可能にする。
Further, as the ionomer contained in the catalyst layer of the present invention, a fluorine-containing ion exchange resin is preferable, and a sulfonic acid type perfluorocarbon polymer is particularly preferable. The sulfonic acid type perfluorocarbon polymer enables long-term chemically stable and rapid hydrogen ion conduction in the cathode electrode.
また、本発明のカソード電極の触媒層の層厚は、通常のアノード電極とカソード電極の間に挟まれる高分子固体電解質と同等であればよく、１～５０μｍであることが好ましく、５～２０μｍであることがより好ましい。
The thickness of the catalyst layer of the cathode electrode of the present invention may be the same as that of the polymer solid electrolyte sandwiched between the ordinary anode electrode and the cathode electrode, and is preferably 1 to 50 μm, preferably 5 to 20 μm. Is more preferable.
固体高分子型燃料電池においては、通常、アノード電極の水素酸化反応の過電圧に比較してカソード電極の酸素還元反応の過電圧が非常に大きいので、生成する過酸化水素によるアイオノマーのスルホン酸基の分解、触媒金属の酸化と溶出および触媒担体導電体の腐食が起こり易く、上記のように、突起形状による撥水性、電子電導性および酸素吸放出性を有する複合金属酸化物で触媒担体導電体を被覆することで防ぐことができる。また、カの撥水性の効果で生成水への酸素の溶存を防ぎ、酸素吸放出性の効果で触媒層内の反応サイトの酸素濃度を増加させて、過電圧を抑えことが、持続的なカソード電極の電極特性を向上させることは、電池の出力特性を安定化させる上で効果的である。
In a solid polymer fuel cell, the overvoltage of the oxygen reduction reaction of the cathode electrode is usually very large compared to the overvoltage of the hydrogen oxidation reaction of the anode electrode, so that the generated hydrogen peroxide decomposes the sulfonic acid group of the ionomer. , Oxidation and elution of catalyst metal and corrosion of catalyst carrier conductor are likely to occur, and as described above, the catalyst carrier conductor is coated with a composite metal oxide having water repellency, electron conductivity and oxygen absorption / release property due to the protrusion shape. It can be prevented by doing. In addition, the water-repellent effect of mosquito prevents the dissolution of oxygen in the generated water, and the oxygen absorption / release effect increases the oxygen concentration at the reaction site in the catalyst layer to suppress overvoltage, which is a continuous cathode. Improving the electrode characteristics of the electrodes is effective in stabilizing the output characteristics of the battery.
一方、アノード電極の構成は特に限定されず、例えば、公知のガス拡散電極の構成を有していてもよい。
On the other hand, the configuration of the anode electrode is not particularly limited, and for example, it may have a known configuration of a gas diffusion electrode.
また、本発明の固体高分子型燃料電池に使用するアノード電極とカソード電極に挟まれる高分子電解質膜は、湿潤状態下で良好なイオン伝導性を示すイオン交換膜であれば特に限定されない。高分子電解質膜を構成する固体高分子材料としては、例えば、スルホン酸基を有するパーフルオロカーボン重合体、ポリサルホン樹脂、ホスホン酸基またはカルボン酸基を有するパーフルオロカーボン重合体等を用いることができる。中でも、スルホン酸型パーフルオロカーボン重合体が好ましい。そして、この高分子電解質膜は、触媒層に含まれるアイオノマーと同じ樹脂からなっていてもよく、異なる樹脂からなっていてもよい。
Further, the polymer electrolyte membrane sandwiched between the anode electrode and the cathode electrode used in the polymer electrolyte fuel cell of the present invention is not particularly limited as long as it is an ion exchange membrane exhibiting good ionic conductivity under a wet state. As the solid polymer material constituting the polymer electrolyte membrane, for example, a perfluorocarbon polymer having a sulfonic acid group, a polysulfone resin, a perfluorocarbon polymer having a phosphonic acid group or a carboxylic acid group and the like can be used. Of these, a sulfonic acid type perfluorocarbon polymer is preferable. The polymer electrolyte membrane may be made of the same resin as the ionomer contained in the catalyst layer, or may be made of a different resin.
本発明のカソード電極の触媒層は、予め、触媒担体導電体の表面を、突起状を有する複合金属酸化物で覆い、その表面に触媒金属粒子を担持させたものとアイオノマーとを、溶媒または分散媒に溶解または分散した塗工液を用いて作製することができる。ここで用いる溶媒または分散媒としては、例えばアルコール、含フッ素アルコール、含フッ素エーテル等が使用できる。そして、塗工液をイオン交換膜またはガス拡散層となるカーボンクロス等に塗工することにより触媒層が形成される。また、別途用意した基材に上記塗工液を塗工して塗工層を形成し、これを高分子固体電解質膜上に転写することによっても高分子固体電解質膜上に触媒層が形成できる。
In the catalyst layer of the cathode electrode of the present invention, the surface of the catalyst carrier conductor is covered with a composite metal oxide having protrusions in advance, and the catalyst metal particles are supported on the surface and the ionomer is dispersed in a solvent or dispersion. It can be prepared by using a coating liquid dissolved or dispersed in a medium. As the solvent or dispersion medium used here, for example, alcohol, fluorine-containing alcohol, fluorine-containing ether and the like can be used. Then, the catalyst layer is formed by applying the coating liquid to an ion exchange membrane, a carbon cloth serving as a gas diffusion layer, or the like. Further, the catalyst layer can also be formed on the polymer solid electrolyte membrane by applying the coating liquid to a separately prepared base material to form a coating layer and transferring the coating layer onto the polymer solid electrolyte membrane. ..
ここで、触媒層をガス拡散層上に形成した場合には、触媒層と高分子固体電解質膜とを接着法やホットプレス法等により接合することが好ましい。また、高分子固体電解質膜上に触媒層を形成した場合には、触媒層のみでカソード電極を構成してもよいが、更に触媒層に隣接してガス拡散層を配置し、カソード電極としてもよい。
Here, when the catalyst layer is formed on the gas diffusion layer, it is preferable to bond the catalyst layer and the polymer solid electrolyte membrane by an adhesion method, a hot press method, or the like. Further, when the catalyst layer is formed on the polymer solid electrolyte membrane, the cathode electrode may be formed only by the catalyst layer, but a gas diffusion layer may be further arranged adjacent to the catalyst layer to serve as the cathode electrode. Good.
カソード電極の外側には、通常ガスの流路が形成されたセパレータが配置され、当該流路にアノード電極には水素を含むガス、カソード電極には酸素を含むガスが供給されて固体高分子型燃料電池が構成される。
A separator having a normal gas flow path is arranged outside the cathode electrode, and a gas containing hydrogen is supplied to the anode electrode and a gas containing oxygen is supplied to the cathode electrode to the flow path to form a solid polymer type. A fuel cell is configured.
（粒径分布の測定）
触媒金属の粒径分布は、透過型電子顕微鏡（Titan Cubed G2 60-300、FEI社製）を用いて、測定１００点数の測定をおこない、算術平均にて平均粒径とした。 (Measurement of particle size distribution)
The particle size distribution of the catalyst metal was measured by measuring 100 points using a transmission electron microscope (Titan Cubed G2 60-300, manufactured by FEI Company), and the average particle size was calculated by arithmetic mean.
触媒金属の粒径分布は、透過型電子顕微鏡（Titan Cubed G2 60-300、FEI社製）を用いて、測定１００点数の測定をおこない、算術平均にて平均粒径とした。 (Measurement of particle size distribution)
The particle size distribution of the catalyst metal was measured by measuring 100 points using a transmission electron microscope (Titan Cubed G2 60-300, manufactured by FEI Company), and the average particle size was calculated by arithmetic mean.
（複合金属酸化物形状の測定）
本発明の突起状を有する複合金属酸化物の形状（高さ、間隔）は、前記触媒金属の粒径分布と同様にして、透過型電子顕微鏡（Titan Cubed G2 60-300、FEI社製）を用いて、測定１００点数の測定をおこない、算術平均にて高さおよび間隔とした。 (Measurement of composite metal oxide shape)
The shape (height, spacing) of the convex composite metal oxide of the present invention is the same as that of the particle size distribution of the catalyst metal, and a transmission electron microscope (Titan Cubed G2 60-300, manufactured by FEI) is used. Using, 100 points were measured, and the height and interval were calculated by arithmetic mean.
本発明の突起状を有する複合金属酸化物の形状（高さ、間隔）は、前記触媒金属の粒径分布と同様にして、透過型電子顕微鏡（Titan Cubed G2 60-300、FEI社製）を用いて、測定１００点数の測定をおこない、算術平均にて高さおよび間隔とした。 (Measurement of composite metal oxide shape)
The shape (height, spacing) of the convex composite metal oxide of the present invention is the same as that of the particle size distribution of the catalyst metal, and a transmission electron microscope (Titan Cubed G2 60-300, manufactured by FEI) is used. Using, 100 points were measured, and the height and interval were calculated by arithmetic mean.
（導電性の測定）
本発明の突起状を有する複合金属酸化物の電気特性は、最終的な触媒粉末を円形状ペレットに成型し、このペレットの四隅に金属極を蒸着した試料を準備し、ホール効果測定装置（Ｒｅｓｉｔｅｓｔ ８３１０、東陽テクニカ製）を用いて比抵抗の測定を行った。 (Measurement of conductivity)
For the electrical characteristics of the convex composite metal oxide of the present invention, a sample in which the final catalyst powder is molded into a circular pellet and metal electrodes are vapor-deposited at the four corners of the pellet is prepared, and a Hall effect measuring device (resistest) is prepared. The resistivity was measured using 8310 (manufactured by Toyo Technica).
本発明の突起状を有する複合金属酸化物の電気特性は、最終的な触媒粉末を円形状ペレットに成型し、このペレットの四隅に金属極を蒸着した試料を準備し、ホール効果測定装置（Ｒｅｓｉｔｅｓｔ ８３１０、東陽テクニカ製）を用いて比抵抗の測定を行った。 (Measurement of conductivity)
For the electrical characteristics of the convex composite metal oxide of the present invention, a sample in which the final catalyst powder is molded into a circular pellet and metal electrodes are vapor-deposited at the four corners of the pellet is prepared, and a Hall effect measuring device (resistest) is prepared. The resistivity was measured using 8310 (manufactured by Toyo Technica).
（撥水度の測定）
以下の実施例１～３において突起を有する複合金属酸化物の撥水度は、最終的な触媒粉末を円形状ペレットに成型した試料を準備し、液滴法（自動極小接触角計MCA－３、協和界面科学（株）製）を用いて行った。参考例１、比較例１～３についても、最終的な触媒粉末を円形状ペレットに成型した試料を用意し、同様に測定した。 (Measurement of water repellency)
For the water repellency of the composite metal oxide having protrusions in Examples 1 to 3 below, a sample obtained by molding the final catalyst powder into circular pellets was prepared, and the sessile drop method (automatic minimum contact angle meter MCA-3) was used. , Kyowa Interface Science Co., Ltd.). For Reference Example 1 and Comparative Examples 1 to 3, a sample obtained by molding the final catalyst powder into circular pellets was prepared and measured in the same manner.
以下の実施例１～３において突起を有する複合金属酸化物の撥水度は、最終的な触媒粉末を円形状ペレットに成型した試料を準備し、液滴法（自動極小接触角計MCA－３、協和界面科学（株）製）を用いて行った。参考例１、比較例１～３についても、最終的な触媒粉末を円形状ペレットに成型した試料を用意し、同様に測定した。 (Measurement of water repellency)
For the water repellency of the composite metal oxide having protrusions in Examples 1 to 3 below, a sample obtained by molding the final catalyst powder into circular pellets was prepared, and the sessile drop method (automatic minimum contact angle meter MCA-3) was used. , Kyowa Interface Science Co., Ltd.). For Reference Example 1 and Comparative Examples 1 to 3, a sample obtained by molding the final catalyst powder into circular pellets was prepared and measured in the same manner.
以下、実施例および比較例を挙げて本発明のカソード電極および固体高分子型燃料電池について詳しく説明する。
Hereinafter, the cathode electrode and the polymer electrolyte fuel cell of the present invention will be described in detail with reference to Examples and Comparative Examples.
（実施例１）
下記の手順でＰｔ（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）の混合物を調製し、ＭＥＡを作成し、ＭＥＡをセルに組み付け、性能評価した。 (Example 1)
Prepare a mixture of Pt (5% by mass) / pyrochlore type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass) according to the following procedure, prepare MEA, assemble MEA into the cell, and evaluate the performance. did.
下記の手順でＰｔ（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）の混合物を調製し、ＭＥＡを作成し、ＭＥＡをセルに組み付け、性能評価した。 (Example 1)
Prepare a mixture of Pt (5% by mass) / pyrochlore type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass) according to the following procedure, prepare MEA, assemble MEA into the cell, and evaluate the performance. did.
（１）塩化錫（II）、塩化タンタル（V）を純水に所定量溶解させて２時間攪拌した。
（２）カーボンブラック（ケッチェンブラックＥＣ３００Ｊ、ＢＥＴ比表面積８００ｇ／ｍ２、ライオン・スペシャリティ・ケミカルズ（株）製）を粉末状に調整し、純水に所定量加え攪拌して懸濁液を作製した。
（３）前記懸濁液に攪拌しながら（１）の溶解液をゆっくりと加えて、希塩酸を用いてｐＨ１．５に調整し、その状態を３時間保持した。その後、ろ過、水洗を３回繰り返し、カーボンブラック粒子にＳｎ２Ｔａ２Ｏ７が被覆されたカーボンブラック粉末を得た。
（４）次に、（３）で得られたＳｎ２Ｔａ２Ｏ７が被覆されたカーボンブラック粉末を、純水に攪拌しながら分散させ、所定量の塩化白金酸(IV)溶液（白金として１質量％）を加えた。そこに、ゆっくりとエタノールを少量加え、４０℃に加温して３時間保持した。白金がＳｎ２Ｔａ２Ｏ７の複合金属酸化物の表面に還元された。
（５）その後、ろ過、水洗を３回繰り返し、８０℃で１２時間乾燥し、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。再び乳鉢で粉砕した。
（６）こうして得られたＰｔ／パイロクロア型Ｓｎ２Ｔａ２Ｏ７／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、白金の触媒金属粒子の平均粒径が３ｎｍ、パイロクロア型Ｓｎ２Ｔａ２Ｏ７ の形状が、平均高さ１０ｎｍ、平均間隔（ピッチ）が１０ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、１５０度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．１Ω・ｃｍであった。
（７）次に、前記Pt／パイロクロア型Ｓｎ２Ｔａ２Ｏ７／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、Ｐｔ（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）の触媒インクを作成した。
（８）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（９）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．３ｍｇ／ｃｍ２、Ｓｎ２Ｔａ２Ｏ７として１．２ｍｇ／ｃｍ２であった。
（１０）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（１１）ＭＥＡをセルに組み付け、性能評価した。 (1) Tin (II) chloride and tantalum (V) chloride were dissolved in pure water in a predetermined amount and stirred for 2 hours.
(2) Carbon black (Ketjen Black EC300J, BET specific surface area 800 g / m2, manufactured by Lion Specialty Chemicals Co., Ltd.) was prepared into powder, and a predetermined amount was added to pure water and stirred to prepare a suspension. ..
(3) The solution of (1) was slowly added to the suspension with stirring to adjust the pH to 1.5 with dilute hydrochloric acid, and the state was maintained for 3 hours. Then, filtration and washing with water were repeated three times to obtain a carbon black powder in which the carbon black particles were coated with Sn 2 Ta 2 O 7 .
(4) Next, the carbon black powder coated with Sn 2 Ta 2 O 7 obtained in (3) was dispersed in pure water with stirring, and a predetermined amount of a chloroplatinic acid (IV) solution (as platinum) was dispersed. 1% by mass) was added. A small amount of ethanol was slowly added thereto, and the mixture was heated to 40 ° C. and kept for 3 hours. Platinum was reduced to the surface of the composite metal oxide of Sn 2 Ta 2 O 7 .
(5) After that, filtration and washing with water were repeated 3 times, dried at 80 ° C. for 12 hours, pulverized in a mortar, and then calcined in an air baking oven at 500 ° C. for 2 hours. It was crushed again in a mortar.
(6) When the Pt / pyrochlore-type Sn 2 Ta 2 O 7 / carbon black powder thus obtained was observed with a transmission electron microscope, the average particle size of the platinum catalyst metal particles was 3 nm, and the pyrochlore-type Sn 2 was observed. The shape of Ta 2 O 7 had an average height of 10 nm and an average interval (pitch) of 10 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 150 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.1Ω · cm.
(7) Next, the Pt / pyrochroma type Sn 2 Ta 2 O 7 / carbon black is mixed in a predetermined amount with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol (Nafion / Carbon = 1). A catalyst ink of 0.0% by mass, Pt (5% by mass) / pyrochloro type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass) was prepared.
(8) The above catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ).
It was used as an electrode film.
(9) the electrode film was analyzed by ICP and total dissolved was 1.2 mg / cm 2 as 0.3mg / cm 2, Sn 2 Ta 2 O 7 as Pt.
(10) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) was performed on the polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(11) MEA was assembled in the cell and the performance was evaluated.
（２）カーボンブラック（ケッチェンブラックＥＣ３００Ｊ、ＢＥＴ比表面積８００ｇ／ｍ２、ライオン・スペシャリティ・ケミカルズ（株）製）を粉末状に調整し、純水に所定量加え攪拌して懸濁液を作製した。
（３）前記懸濁液に攪拌しながら（１）の溶解液をゆっくりと加えて、希塩酸を用いてｐＨ１．５に調整し、その状態を３時間保持した。その後、ろ過、水洗を３回繰り返し、カーボンブラック粒子にＳｎ２Ｔａ２Ｏ７が被覆されたカーボンブラック粉末を得た。
（４）次に、（３）で得られたＳｎ２Ｔａ２Ｏ７が被覆されたカーボンブラック粉末を、純水に攪拌しながら分散させ、所定量の塩化白金酸(IV)溶液（白金として１質量％）を加えた。そこに、ゆっくりとエタノールを少量加え、４０℃に加温して３時間保持した。白金がＳｎ２Ｔａ２Ｏ７の複合金属酸化物の表面に還元された。
（５）その後、ろ過、水洗を３回繰り返し、８０℃で１２時間乾燥し、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。再び乳鉢で粉砕した。
（６）こうして得られたＰｔ／パイロクロア型Ｓｎ２Ｔａ２Ｏ７／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、白金の触媒金属粒子の平均粒径が３ｎｍ、パイロクロア型Ｓｎ２Ｔａ２Ｏ７ の形状が、平均高さ１０ｎｍ、平均間隔（ピッチ）が１０ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、１５０度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．１Ω・ｃｍであった。
（７）次に、前記Pt／パイロクロア型Ｓｎ２Ｔａ２Ｏ７／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、Ｐｔ（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）の触媒インクを作成した。
（８）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（９）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．３ｍｇ／ｃｍ２、Ｓｎ２Ｔａ２Ｏ７として１．２ｍｇ／ｃｍ２であった。
（１０）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（１１）ＭＥＡをセルに組み付け、性能評価した。 (1) Tin (II) chloride and tantalum (V) chloride were dissolved in pure water in a predetermined amount and stirred for 2 hours.
(2) Carbon black (Ketjen Black EC300J, BET specific surface area 800 g / m2, manufactured by Lion Specialty Chemicals Co., Ltd.) was prepared into powder, and a predetermined amount was added to pure water and stirred to prepare a suspension. ..
(3) The solution of (1) was slowly added to the suspension with stirring to adjust the pH to 1.5 with dilute hydrochloric acid, and the state was maintained for 3 hours. Then, filtration and washing with water were repeated three times to obtain a carbon black powder in which the carbon black particles were coated with Sn 2 Ta 2 O 7 .
(4) Next, the carbon black powder coated with Sn 2 Ta 2 O 7 obtained in (3) was dispersed in pure water with stirring, and a predetermined amount of a chloroplatinic acid (IV) solution (as platinum) was dispersed. 1% by mass) was added. A small amount of ethanol was slowly added thereto, and the mixture was heated to 40 ° C. and kept for 3 hours. Platinum was reduced to the surface of the composite metal oxide of Sn 2 Ta 2 O 7 .
(5) After that, filtration and washing with water were repeated 3 times, dried at 80 ° C. for 12 hours, pulverized in a mortar, and then calcined in an air baking oven at 500 ° C. for 2 hours. It was crushed again in a mortar.
(6) When the Pt / pyrochlore-type Sn 2 Ta 2 O 7 / carbon black powder thus obtained was observed with a transmission electron microscope, the average particle size of the platinum catalyst metal particles was 3 nm, and the pyrochlore-type Sn 2 was observed. The shape of Ta 2 O 7 had an average height of 10 nm and an average interval (pitch) of 10 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 150 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.1Ω · cm.
(7) Next, the Pt / pyrochroma type Sn 2 Ta 2 O 7 / carbon black is mixed in a predetermined amount with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol (Nafion / Carbon = 1). A catalyst ink of 0.0% by mass, Pt (5% by mass) / pyrochloro type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass) was prepared.
(8) The above catalyst ink was cast on a Teflon (registered trademark) resin film (
It was used as an electrode film.
(9) the electrode film was analyzed by ICP and total dissolved was 1.2 mg / cm 2 as 0.3mg / cm 2, Sn 2 Ta 2 O 7 as Pt.
(10) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) was performed on the polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(11) MEA was assembled in the cell and the performance was evaluated.
（実施例２）
実施例２は、触媒金属を、Ｐｔ単一金属からコアシェル型触媒金属（シェル層Ｐｔ／コア層Ｐｄ・Ｒｕ・Ｃｏ合金）に代えた以外は、実施例１と同様にして、コアシェル型触媒金属（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）を用いたＭＥＡを作製し、単セルで性能評価した。 (Example 2)
In Example 2, the core-shell type catalyst metal is the same as in Example 1 except that the catalyst metal is changed from the Pt single metal to the core-shell type catalyst metal (shell layer Pt / core layer Pd / Ru / Co alloy). An MEA was prepared using (5% by mass) / pyrochlore type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass), and its performance was evaluated in a single cell.
実施例２は、触媒金属を、Ｐｔ単一金属からコアシェル型触媒金属（シェル層Ｐｔ／コア層Ｐｄ・Ｒｕ・Ｃｏ合金）に代えた以外は、実施例１と同様にして、コアシェル型触媒金属（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）を用いたＭＥＡを作製し、単セルで性能評価した。 (Example 2)
In Example 2, the core-shell type catalyst metal is the same as in Example 1 except that the catalyst metal is changed from the Pt single metal to the core-shell type catalyst metal (shell layer Pt / core layer Pd / Ru / Co alloy). An MEA was prepared using (5% by mass) / pyrochlore type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass), and its performance was evaluated in a single cell.
前記コアシェル触媒金属は、下記の手順で作製した。
（１）実施例１の（３）で、得られたＳｎ２Ｔａ２Ｏ７が被覆されたカーボンブラック粉末を、純水に攪拌しながら分散させ、塩化パラジウム溶液（Ｐｄとして１質量％）と塩化ルテニウム溶液（Ｒｕとして１質量％）塩化コバルト溶液（Ｃｏとして１質量％）とを各所定量を加えた。
（２）そこに、ゆっくりとエタノールを少量加え、４０℃に加温して３時間保持した。ＰｄとＲｕとＣｏとがＳｎ２Ｔａ２Ｏ７の複合金属酸化物の表面に還元した。その後、ろ過、水洗を３回繰り返し、８０℃で１２時間乾燥し、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。再び乳鉢で粉砕した。
（３）次に、（２）で得られたコア部の触媒が担持されたＳｎ２Ｔａ２Ｏ７被覆カーボンブラック粉末を、純水に攪拌しながら分散させ、塩化白金酸（IV）溶液を所定量加えた。そこに、ゆっくりとエタノールを少量加え、４０℃に加温して３時間保持した。
（４）その後、ろ過、水洗を３回繰り返し、８０℃で１２時間乾燥し、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。再び乳鉢で粉砕した。
（５）得られたコアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）粒子の平均粒径が３ｎｍ、パイロクロア型Ｓｎ２Ｔａ２Ｏ７の形状が、平均高さ１０ｎｍ、平均間隔（ピッチ）が１０ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、１５０度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．１Ω・ｃｍであった。
（６）次に、前記コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）の触媒インクを作成した。
（７）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、電極膜とした。
（８）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．０５ｍｇ／ｃｍ２、Ｐｄとして０．０３ｍｇ／ｃｍ２、Ｒｕとして０．１０ｍｇ／ｃｍ２、Ｃｏとして０．１１ｍｇ／ｃｍ２、Ｓｎ２Ｔａ２Ｏ７として１．２ｍｇ／ｃｍ２であった。
（９）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（１０）ＭＥＡをセルに組み付け、性能評価した。 The core-shell catalyst metal was produced by the following procedure.
(1) The carbon black powder coated with Sn 2 Ta 2 O 7 obtained in (3) of Example 1 was dispersed in pure water with stirring, and combined with a palladium chloride solution (1% by mass as Pd). A predetermined amount of a ruthenium chloride solution (1% by mass as Ru) and a cobalt chloride solution (1% by mass as Co) were added.
(2) A small amount of ethanol was slowly added thereto, and the mixture was heated to 40 ° C. and kept for 3 hours. Pd, Ru and Co were reduced to the surface of the composite metal oxide of Sn 2 Ta 2 O 7 . Then, filtration and washing with water were repeated 3 times, dried at 80 ° C. for 12 hours, pulverized in a mortar, and then calcined in an air baking oven at 500 ° C. for 2 hours. It was crushed again in a mortar.
(3) Next, the Sn 2 Ta 2 O 7- coated carbon black powder on which the catalyst of the core portion obtained in (2) was supported was dispersed in pure water with stirring to prepare a chloroplatinic acid (IV) solution. A predetermined amount was added. A small amount of ethanol was slowly added thereto, and the mixture was heated to 40 ° C. and kept for 3 hours.
(4) After that, filtration and washing with water were repeated 3 times, dried at 80 ° C. for 12 hours, pulverized in a mortar, and then calcined in an air baking oven at 500 ° C. for 2 hours. It was crushed again in a mortar.
(5) When the obtained core-shell type catalyst (Pt / Pd / Ru / Co alloy) / pyrochlor type Sn 2 Ta 2 O 7 / carbon black powder was observed with a transmission electron microscope, the core-shell type catalyst (Pt) was observed. / Pd ・ Ru ・ Co alloy) The average particle size of the particles was 3 nm, the shape of the pyrochlor type Sn 2 Ta 2 O 7 was 10 nm in average height and 10 nm in average interval (pitch). Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 150 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.1Ω · cm.
(6) Next, the core-shell type catalyst (Pt / Pd / Ru / Co alloy) / pyrochlor type Sn 2 Ta 2 O 7 / carbon black is added to ion-exchanged water, ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol. (Nafion / Carbon = 1.0% by mass, core-shell type catalyst (Pt / Pd / Ru / Co alloy) (5% by mass) / pyrochroma type Sn 2 Ta 2 O 7 (20%) / carbon A black (75% by mass) catalyst ink was prepared.
(7) The catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ) to obtain an electrode film.
(8) When the electrode film was completely dissolved and ICP analyzed, Pt was 0.05 mg / cm 2 , Pd was 0.03 mg / cm 2 , Ru was 0.10 mg / cm 2 , and Co was 0.11 mg / cm. It was 1.2 mg / cm 2 as cm 2 and Sn 2 Ta 2 O 7 .
(9) Using the obtained cathode electrode membrane and an electrode membrane made of a commercially available catalyst according to Comparative Example 1 for the anode electrode, thermocompression bonding (150) was performed on a polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(10) MEA was assembled in the cell and the performance was evaluated.
（１）実施例１の（３）で、得られたＳｎ２Ｔａ２Ｏ７が被覆されたカーボンブラック粉末を、純水に攪拌しながら分散させ、塩化パラジウム溶液（Ｐｄとして１質量％）と塩化ルテニウム溶液（Ｒｕとして１質量％）塩化コバルト溶液（Ｃｏとして１質量％）とを各所定量を加えた。
（２）そこに、ゆっくりとエタノールを少量加え、４０℃に加温して３時間保持した。ＰｄとＲｕとＣｏとがＳｎ２Ｔａ２Ｏ７の複合金属酸化物の表面に還元した。その後、ろ過、水洗を３回繰り返し、８０℃で１２時間乾燥し、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。再び乳鉢で粉砕した。
（３）次に、（２）で得られたコア部の触媒が担持されたＳｎ２Ｔａ２Ｏ７被覆カーボンブラック粉末を、純水に攪拌しながら分散させ、塩化白金酸（IV）溶液を所定量加えた。そこに、ゆっくりとエタノールを少量加え、４０℃に加温して３時間保持した。
（４）その後、ろ過、水洗を３回繰り返し、８０℃で１２時間乾燥し、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。再び乳鉢で粉砕した。
（５）得られたコアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）粒子の平均粒径が３ｎｍ、パイロクロア型Ｓｎ２Ｔａ２Ｏ７の形状が、平均高さ１０ｎｍ、平均間隔（ピッチ）が１０ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、１５０度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．１Ω・ｃｍであった。
（６）次に、前記コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）の触媒インクを作成した。
（７）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、電極膜とした。
（８）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．０５ｍｇ／ｃｍ２、Ｐｄとして０．０３ｍｇ／ｃｍ２、Ｒｕとして０．１０ｍｇ／ｃｍ２、Ｃｏとして０．１１ｍｇ／ｃｍ２、Ｓｎ２Ｔａ２Ｏ７として１．２ｍｇ／ｃｍ２であった。
（９）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（１０）ＭＥＡをセルに組み付け、性能評価した。 The core-shell catalyst metal was produced by the following procedure.
(1) The carbon black powder coated with Sn 2 Ta 2 O 7 obtained in (3) of Example 1 was dispersed in pure water with stirring, and combined with a palladium chloride solution (1% by mass as Pd). A predetermined amount of a ruthenium chloride solution (1% by mass as Ru) and a cobalt chloride solution (1% by mass as Co) were added.
(2) A small amount of ethanol was slowly added thereto, and the mixture was heated to 40 ° C. and kept for 3 hours. Pd, Ru and Co were reduced to the surface of the composite metal oxide of Sn 2 Ta 2 O 7 . Then, filtration and washing with water were repeated 3 times, dried at 80 ° C. for 12 hours, pulverized in a mortar, and then calcined in an air baking oven at 500 ° C. for 2 hours. It was crushed again in a mortar.
(3) Next, the Sn 2 Ta 2 O 7- coated carbon black powder on which the catalyst of the core portion obtained in (2) was supported was dispersed in pure water with stirring to prepare a chloroplatinic acid (IV) solution. A predetermined amount was added. A small amount of ethanol was slowly added thereto, and the mixture was heated to 40 ° C. and kept for 3 hours.
(4) After that, filtration and washing with water were repeated 3 times, dried at 80 ° C. for 12 hours, pulverized in a mortar, and then calcined in an air baking oven at 500 ° C. for 2 hours. It was crushed again in a mortar.
(5) When the obtained core-shell type catalyst (Pt / Pd / Ru / Co alloy) / pyrochlor type Sn 2 Ta 2 O 7 / carbon black powder was observed with a transmission electron microscope, the core-shell type catalyst (Pt) was observed. / Pd ・ Ru ・ Co alloy) The average particle size of the particles was 3 nm, the shape of the pyrochlor type Sn 2 Ta 2 O 7 was 10 nm in average height and 10 nm in average interval (pitch). Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 150 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.1Ω · cm.
(6) Next, the core-shell type catalyst (Pt / Pd / Ru / Co alloy) / pyrochlor type Sn 2 Ta 2 O 7 / carbon black is added to ion-exchanged water, ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol. (Nafion / Carbon = 1.0% by mass, core-shell type catalyst (Pt / Pd / Ru / Co alloy) (5% by mass) / pyrochroma type Sn 2 Ta 2 O 7 (20%) / carbon A black (75% by mass) catalyst ink was prepared.
(7) The catalyst ink was cast on a Teflon (registered trademark) resin film (
(8) When the electrode film was completely dissolved and ICP analyzed, Pt was 0.05 mg / cm 2 , Pd was 0.03 mg / cm 2 , Ru was 0.10 mg / cm 2 , and Co was 0.11 mg / cm. It was 1.2 mg / cm 2 as cm 2 and Sn 2 Ta 2 O 7 .
(9) Using the obtained cathode electrode membrane and an electrode membrane made of a commercially available catalyst according to Comparative Example 1 for the anode electrode, thermocompression bonding (150) was performed on a polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(10) MEA was assembled in the cell and the performance was evaluated.
（実施例３）
実施例３は、パイロクロア型Ｓｎ２Ｔａ２Ｏ７を、ＴａドープＳｎＯ２に代えた以外は、実施例２と同様にして、コアシェル型触媒金属（５質量％）／ＴａドープＳｎＯ２（２０％）／カーボンブラック（７５質量％）を用いたＭＥＡを作製し、単セルで性能評価した。 (Example 3)
Example 3 is the same as in Example 2 except that the pyrochlore-type Sn 2 Ta 2 O 7 is replaced with Ta-doped SnO 2 , and the core-shell type catalyst metal (5% by mass) / Ta-doped SnO 2 (20%). ) / MEA using carbon black (75% by mass) was prepared, and the performance was evaluated with a single cell.
実施例３は、パイロクロア型Ｓｎ２Ｔａ２Ｏ７を、ＴａドープＳｎＯ２に代えた以外は、実施例２と同様にして、コアシェル型触媒金属（５質量％）／ＴａドープＳｎＯ２（２０％）／カーボンブラック（７５質量％）を用いたＭＥＡを作製し、単セルで性能評価した。 (Example 3)
Example 3 is the same as in Example 2 except that the pyrochlore-type Sn 2 Ta 2 O 7 is replaced with Ta-doped SnO 2 , and the core-shell type catalyst metal (5% by mass) / Ta-doped SnO 2 (20%). ) / MEA using carbon black (75% by mass) was prepared, and the performance was evaluated with a single cell.
前記ＴａドープＳｎＯ２の複合金属酸化物は、下記の手順で作製した。
（１）塩化錫（II）を純水に所定量溶解させて２時間攪拌した。
（２）カーボンブラック（ケッチェンブラックＥＣ３００Ｊ、ＢＥＴ比表面積８００ｇ／ｍ２、ライオン・スペシャリティ・ケミカルズ（株）製）を粉末状に調整し、純水に所定量加え攪拌して懸濁液を作製した。
（３）前記懸濁液に攪拌しながら（１）の溶解液をゆっくりと加えて、希塩酸を用いてｐＨ１．５に調整し、その状態を３時間保持した。
（４）塩化タンタル（V）を純水に所定量溶解させて２時間攪拌した。
（５）次に、（３）の懸濁液を攪拌しながら、前記塩化タンタル（V）溶液をゆっくりと所定量加え、３０℃に加温して、３時間保持した。
（６）その後、ろ過、水洗を３回繰り返し、ＴａドープＳｎＯ２が被覆されたカーボンブラック粉末を得た。
（７）前記ＴａドープＳｎＯ２が被覆されたカーボンブラック粉末を少量採取し、８０℃で１２時間乾燥し、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。
（８）得られたＴａドープＳｎＯ２が被覆されたカーボンブラック粉末を、全溶解してＩＣＰ分析したところ、ＴａがＳｎＯ２に２．１質量％含まれていた。
（９）得られたコアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／ＴａドープＳｎＯ２／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）粒子の平均粒径が３ｎｍ、ＴａドープＳｎＯ２の形状が、平均高さ１０ｎｍ、平均間隔（ピッチ）が１０ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、１４５度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．２Ω・ｃｍであった。
（１０）次に、前記コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／ＴａドープＳｎＯ２／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）の触媒インクを作成した。
（１１）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、電極膜とした。
（１２）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．０５ｍｇ／ｃｍ２、Ｐｄとして０．０３ｍｇ／ｃｍ２、Ｒｕとして０．１０ｍｇ／ｃｍ２、Ｃｏとして０．１１ｍｇ／ｃｍ２、ＴａドープＳｎＯ２として１．２ｍｇ／ｃｍ２であった。
（１３）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（１４）ＭＥＡをセルに組み付け、性能評価した。 The composite metal oxide of Ta-doped SnO 2 was prepared by the following procedure.
(1) A predetermined amount of tin (II) chloride was dissolved in pure water and stirred for 2 hours.
(2) Carbon black (Ketjen Black EC300J, BET specific surface area 800 g / m 2 , manufactured by Lion Specialty Chemicals Co., Ltd.) is prepared into powder, and a predetermined amount is added to pure water and stirred to prepare a suspension. did.
(3) The solution of (1) was slowly added to the suspension with stirring to adjust the pH to 1.5 with dilute hydrochloric acid, and the state was maintained for 3 hours.
(4) A predetermined amount of tantalum chloride (V) was dissolved in pure water and stirred for 2 hours.
(5) Next, while stirring the suspension of (3), the tantalum (V) chloride solution was slowly added in a predetermined amount, heated to 30 ° C., and held for 3 hours.
(6) After that, filtration and washing with water were repeated three times to obtain a carbon black powder coated with Ta-doped SnO 2 .
(7) A small amount of the carbon black powder coated with the Ta-doped SnO 2 was collected, dried at 80 ° C. for 12 hours, pulverized in a mortar, and then calcined in an atmospheric baking oven at 500 ° C. for 2 hours.
(8) When the obtained carbon black powder coated with Ta-doped SnO 2 was completely dissolved and subjected to ICP analysis, Ta was contained in SnO 2 in an amount of 2.1% by mass.
(9) When the obtained core-shell type catalyst (Pt / Pd / Ru / Co alloy) / Ta-doped SnO 2 / carbon black powder was observed with a transmission electron microscope, the core-shell type catalyst (Pt / Pd / Ru / Ru) was observed. The average particle size of the (Co alloy) particles was 3 nm, the shape of the Ta-doped SnO 2 was 10 nm in average height, and the average interval (pitch) was 10 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 145 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.2Ω · cm.
(10) Next, the core-shell type catalyst (Pt / Pd / Ru / Co alloy) / Ta-doped SnO 2 / carbon black is mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount. (Nafion / Carbon = 1.0% by mass, core-shell type catalyst (Pt / Pd / Ru / Co alloy) (5% by mass) / pyrochroma type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass) %) Catalyst ink was prepared.
(11) The catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ) to obtain an electrode film.
(12) When the electrode membrane was completely dissolved and ICP analyzed, Pt was 0.05 mg / cm 2 , Pd was 0.03 mg / cm 2 , Ru was 0.10 mg / cm 2 , and Co was 0.11 mg / cm. It was 1.2 mg / cm 2 as cm 2 and Ta-doped SnO 2 .
(13) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) to a polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(14) MEA was assembled in the cell and its performance was evaluated.
（１）塩化錫（II）を純水に所定量溶解させて２時間攪拌した。
（２）カーボンブラック（ケッチェンブラックＥＣ３００Ｊ、ＢＥＴ比表面積８００ｇ／ｍ２、ライオン・スペシャリティ・ケミカルズ（株）製）を粉末状に調整し、純水に所定量加え攪拌して懸濁液を作製した。
（３）前記懸濁液に攪拌しながら（１）の溶解液をゆっくりと加えて、希塩酸を用いてｐＨ１．５に調整し、その状態を３時間保持した。
（４）塩化タンタル（V）を純水に所定量溶解させて２時間攪拌した。
（５）次に、（３）の懸濁液を攪拌しながら、前記塩化タンタル（V）溶液をゆっくりと所定量加え、３０℃に加温して、３時間保持した。
（６）その後、ろ過、水洗を３回繰り返し、ＴａドープＳｎＯ２が被覆されたカーボンブラック粉末を得た。
（７）前記ＴａドープＳｎＯ２が被覆されたカーボンブラック粉末を少量採取し、８０℃で１２時間乾燥し、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。
（８）得られたＴａドープＳｎＯ２が被覆されたカーボンブラック粉末を、全溶解してＩＣＰ分析したところ、ＴａがＳｎＯ２に２．１質量％含まれていた。
（９）得られたコアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／ＴａドープＳｎＯ２／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）粒子の平均粒径が３ｎｍ、ＴａドープＳｎＯ２の形状が、平均高さ１０ｎｍ、平均間隔（ピッチ）が１０ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、１４５度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．２Ω・ｃｍであった。
（１０）次に、前記コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／ＴａドープＳｎＯ２／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）（５質量％）／パイロクロア型Ｓｎ２Ｔａ２Ｏ７（２０％）／カーボンブラック（７５質量％）の触媒インクを作成した。
（１１）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、電極膜とした。
（１２）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．０５ｍｇ／ｃｍ２、Ｐｄとして０．０３ｍｇ／ｃｍ２、Ｒｕとして０．１０ｍｇ／ｃｍ２、Ｃｏとして０．１１ｍｇ／ｃｍ２、ＴａドープＳｎＯ２として１．２ｍｇ／ｃｍ２であった。
（１３）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（１４）ＭＥＡをセルに組み付け、性能評価した。 The composite metal oxide of Ta-doped SnO 2 was prepared by the following procedure.
(1) A predetermined amount of tin (II) chloride was dissolved in pure water and stirred for 2 hours.
(2) Carbon black (Ketjen Black EC300J, BET specific surface area 800 g / m 2 , manufactured by Lion Specialty Chemicals Co., Ltd.) is prepared into powder, and a predetermined amount is added to pure water and stirred to prepare a suspension. did.
(3) The solution of (1) was slowly added to the suspension with stirring to adjust the pH to 1.5 with dilute hydrochloric acid, and the state was maintained for 3 hours.
(4) A predetermined amount of tantalum chloride (V) was dissolved in pure water and stirred for 2 hours.
(5) Next, while stirring the suspension of (3), the tantalum (V) chloride solution was slowly added in a predetermined amount, heated to 30 ° C., and held for 3 hours.
(6) After that, filtration and washing with water were repeated three times to obtain a carbon black powder coated with Ta-doped SnO 2 .
(7) A small amount of the carbon black powder coated with the Ta-doped SnO 2 was collected, dried at 80 ° C. for 12 hours, pulverized in a mortar, and then calcined in an atmospheric baking oven at 500 ° C. for 2 hours.
(8) When the obtained carbon black powder coated with Ta-doped SnO 2 was completely dissolved and subjected to ICP analysis, Ta was contained in SnO 2 in an amount of 2.1% by mass.
(9) When the obtained core-shell type catalyst (Pt / Pd / Ru / Co alloy) / Ta-doped SnO 2 / carbon black powder was observed with a transmission electron microscope, the core-shell type catalyst (Pt / Pd / Ru / Ru) was observed. The average particle size of the (Co alloy) particles was 3 nm, the shape of the Ta-doped SnO 2 was 10 nm in average height, and the average interval (pitch) was 10 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 145 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.2Ω · cm.
(10) Next, the core-shell type catalyst (Pt / Pd / Ru / Co alloy) / Ta-doped SnO 2 / carbon black is mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount. (Nafion / Carbon = 1.0% by mass, core-shell type catalyst (Pt / Pd / Ru / Co alloy) (5% by mass) / pyrochroma type Sn 2 Ta 2 O 7 (20%) / carbon black (75% by mass) %) Catalyst ink was prepared.
(11) The catalyst ink was cast on a Teflon (registered trademark) resin film (
(12) When the electrode membrane was completely dissolved and ICP analyzed, Pt was 0.05 mg / cm 2 , Pd was 0.03 mg / cm 2 , Ru was 0.10 mg / cm 2 , and Co was 0.11 mg / cm. It was 1.2 mg / cm 2 as cm 2 and Ta-doped SnO 2 .
(13) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) to a polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(14) MEA was assembled in the cell and its performance was evaluated.
（参考例１）
参考例１は、パイロクロア型Ｓｎ２Ｔａ２Ｏ７を除いた以外は実施例２と同様にして、コアシェル型触媒金属（５質量％）／カーボンブラック（７５質量％）を用いたＭＥＡを作製し、単セルで性能評価した。 (Reference example 1)
In Reference Example 1, an MEA using a core-shell type catalyst metal (5% by mass) / carbon black (75% by mass) was prepared in the same manner as in Example 2 except that the pyrochlore type Sn 2 Ta 2 O 7 was removed. , Performance was evaluated with a single cell.
参考例１は、パイロクロア型Ｓｎ２Ｔａ２Ｏ７を除いた以外は実施例２と同様にして、コアシェル型触媒金属（５質量％）／カーボンブラック（７５質量％）を用いたＭＥＡを作製し、単セルで性能評価した。 (Reference example 1)
In Reference Example 1, an MEA using a core-shell type catalyst metal (5% by mass) / carbon black (75% by mass) was prepared in the same manner as in Example 2 except that the pyrochlore type Sn 2 Ta 2 O 7 was removed. , Performance was evaluated with a single cell.
（１）得られたコアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）粒子の平均粒径が３ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、９０度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．５Ω・ｃｍであった。
（２）次に、前記コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）（５質量％）／カーボンブラック（９５質量％）の触媒インクを作成した。
（３）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（４）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．０５ｍｇ／ｃｍ２、Ｐｄとして０．０３ｍｇ／ｃｍ２、Ｒｕとして０．１０ｍｇ／ｃｍ２、Ｃｏとして０．１１ｍｇ／ｃｍ２であった。
（５）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（６）ＭＥＡをセルに組み付け、性能評価した。 (1) When the obtained core-shell catalyst (Pt / Pd / Ru / Co alloy) / carbon black powder was observed with a transmission electron microscope, the core-shell catalyst (Pt / Pd / Ru / Co alloy) particles were observed. The average particle size of was 3 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 90 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.5Ω · cm.
(2) Next, the core-shell type catalyst (Pt / Pd / Ru / Co alloy) / carbon black is mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount (Nafion /). A catalyst ink having Carbon = 1.0% by mass and a core-shell type catalyst (Pt / Pd / Ru / Co alloy) (5% by mass) / carbon black (95% by mass) was prepared.
(3) The catalyst ink is cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ).
It was used as an electrode film.
(4) When the electrode membrane was completely dissolved and ICP analyzed, Pt was 0.05 mg / cm 2 , Pd was 0.03 mg / cm 2 , Ru was 0.10 mg / cm 2 , and Co was 0.11 mg / cm. It was cm 2 .
(5) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) to a polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(6) MEA was assembled in the cell and the performance was evaluated.
（２）次に、前記コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、コアシェル型触媒（Ｐｔ／Ｐｄ・Ｒｕ・Ｃｏ合金）（５質量％）／カーボンブラック（９５質量％）の触媒インクを作成した。
（３）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（４）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．０５ｍｇ／ｃｍ２、Ｐｄとして０．０３ｍｇ／ｃｍ２、Ｒｕとして０．１０ｍｇ／ｃｍ２、Ｃｏとして０．１１ｍｇ／ｃｍ２であった。
（５）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（６）ＭＥＡをセルに組み付け、性能評価した。 (1) When the obtained core-shell catalyst (Pt / Pd / Ru / Co alloy) / carbon black powder was observed with a transmission electron microscope, the core-shell catalyst (Pt / Pd / Ru / Co alloy) particles were observed. The average particle size of was 3 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 90 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.5Ω · cm.
(2) Next, the core-shell type catalyst (Pt / Pd / Ru / Co alloy) / carbon black is mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount (Nafion /). A catalyst ink having Carbon = 1.0% by mass and a core-shell type catalyst (Pt / Pd / Ru / Co alloy) (5% by mass) / carbon black (95% by mass) was prepared.
(3) The catalyst ink is cast on a Teflon (registered trademark) resin film (
It was used as an electrode film.
(4) When the electrode membrane was completely dissolved and ICP analyzed, Pt was 0.05 mg / cm 2 , Pd was 0.03 mg / cm 2 , Ru was 0.10 mg / cm 2 , and Co was 0.11 mg / cm. It was cm 2 .
(5) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) to a polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(6) MEA was assembled in the cell and the performance was evaluated.
（比較例１）
比較例１は、触媒を市販のカーボンブラックに白金が担持されたＴＥＣ１０Ｅ５０Ｅ（Ｐｔとして５０質量％、田中貴金属工業製）を用いて、ＭＥＡを作成し、ＭＥＡをセルに組み付け、性能評価した。 (Comparative Example 1)
In Comparative Example 1, MEA was prepared using TEC10E50E (50% by mass as Pt, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) in which platinum was supported on commercially available carbon black, and the MEA was assembled into a cell to evaluate its performance.
比較例１は、触媒を市販のカーボンブラックに白金が担持されたＴＥＣ１０Ｅ５０Ｅ（Ｐｔとして５０質量％、田中貴金属工業製）を用いて、ＭＥＡを作成し、ＭＥＡをセルに組み付け、性能評価した。 (Comparative Example 1)
In Comparative Example 1, MEA was prepared using TEC10E50E (50% by mass as Pt, manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) in which platinum was supported on commercially available carbon black, and the MEA was assembled into a cell to evaluate its performance.
（１）市販のＴＥＣ１０Ｅ５０Ｅの触媒粉末を、透過型電子顕微鏡にて観察したところ、白金の触媒金属粒子の平均粒径が４ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、９０度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．０１Ω・ｃｍであった。
（２）次に、前記市販のＴＥＣ１０Ｅ５０Ｅの触媒粉末を、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、Ｐｔ（５質量％）／カーボンブラック（９５質量％）の触媒インクを作成した。
（３）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（４）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．３ｍｇ／ｃｍ２であった。
（５）得られた前記電極膜を、カソード電極およびアノード電極ともに用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（６）ＭＥＡをセルに組み付け、性能評価した。 (1) When the commercially available TEC10E50E catalyst powder was observed with a transmission electron microscope, the average particle size of the platinum catalyst metal particles was 4 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 90 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.01Ω · cm.
(2) Next, the commercially available catalyst powder of TEC10E50E was mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount (Nafion / Carbon = 1.0% by mass, Pt (2). A catalyst ink of 5% by mass) / carbon black (95% by mass) was prepared.
(3) The catalyst ink is cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ).
It was used as an electrode film.
(4) When the electrode film was completely dissolved and ICP analyzed, it was 0.3 mg / cm 2 as Pt.
(5) The obtained electrode film was thermocompression-bonded (150 ° C.) to a polymer solid electrolyte membrane (NafionNR211, t = 25 μm) using both the cathode electrode and the anode electrode to prepare MEA.
(6) MEA was assembled in the cell and the performance was evaluated.
（２）次に、前記市販のＴＥＣ１０Ｅ５０Ｅの触媒粉末を、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、Ｐｔ（５質量％）／カーボンブラック（９５質量％）の触媒インクを作成した。
（３）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（４）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．３ｍｇ／ｃｍ２であった。
（５）得られた前記電極膜を、カソード電極およびアノード電極ともに用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（６）ＭＥＡをセルに組み付け、性能評価した。 (1) When the commercially available TEC10E50E catalyst powder was observed with a transmission electron microscope, the average particle size of the platinum catalyst metal particles was 4 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 90 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.01Ω · cm.
(2) Next, the commercially available catalyst powder of TEC10E50E was mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount (Nafion / Carbon = 1.0% by mass, Pt (2). A catalyst ink of 5% by mass) / carbon black (95% by mass) was prepared.
(3) The catalyst ink is cast on a Teflon (registered trademark) resin film (
It was used as an electrode film.
(4) When the electrode film was completely dissolved and ICP analyzed, it was 0.3 mg / cm 2 as Pt.
(5) The obtained electrode film was thermocompression-bonded (150 ° C.) to a polymer solid electrolyte membrane (NafionNR211, t = 25 μm) using both the cathode electrode and the anode electrode to prepare MEA.
(6) MEA was assembled in the cell and the performance was evaluated.
（比較例２）
比較例２は、パイロクロア型Ｓｎ２Ｔａ２Ｏ７に代えて、パイロクロア型Ｃｅ２Ｚr２Ｏ７を複合金属酸化物として使用し、パイロクロア型Ｃｅ２Ｚｒ２Ｏ７に触媒金属粒子は担持させず、複合金属酸化物と触媒金属粒子とをそれぞれ個別にカーボンブラックに担持した以外は、実施例１と同様にしてＭＥＡを作成し、ＭＥＡをセルに組み付け、性能評価した。 (Comparative Example 2)
In Comparative Example 2, instead of the pyrochlore type Sn 2 Ta 2 O 7 , the pyrochlore type Ce 2 Zr 2 O 7 was used as the composite metal oxide, and the pyrochlore type Ce 2 Zr 2 O 7 was not supported with the catalyst metal particles. , The composite metal oxide and the catalyst metal particles were individually supported on carbon black, but MEA was prepared in the same manner as in Example 1, and the MEA was assembled into the cell to evaluate the performance.
比較例２は、パイロクロア型Ｓｎ２Ｔａ２Ｏ７に代えて、パイロクロア型Ｃｅ２Ｚr２Ｏ７を複合金属酸化物として使用し、パイロクロア型Ｃｅ２Ｚｒ２Ｏ７に触媒金属粒子は担持させず、複合金属酸化物と触媒金属粒子とをそれぞれ個別にカーボンブラックに担持した以外は、実施例１と同様にしてＭＥＡを作成し、ＭＥＡをセルに組み付け、性能評価した。 (Comparative Example 2)
In Comparative Example 2, instead of the pyrochlore type Sn 2 Ta 2 O 7 , the pyrochlore type Ce 2 Zr 2 O 7 was used as the composite metal oxide, and the pyrochlore type Ce 2 Zr 2 O 7 was not supported with the catalyst metal particles. , The composite metal oxide and the catalyst metal particles were individually supported on carbon black, but MEA was prepared in the same manner as in Example 1, and the MEA was assembled into the cell to evaluate the performance.
（１）硝酸二アンモニウムセリウムと、オキシ硝酸ジルコニウムとを純水に所定量溶解させて２時間攪拌した。
（２）１２０℃で、水分を蒸発させた後、真空乾燥した。その後、大気焼成炉にて３５０℃で、５時間焼成した。
（３）還元ガス（Ｈ２、２％）雰囲気中９００℃で２時間保持、その後不活性ガス（Ｎ２）に切替えて徐冷した。
（４）得られた粉末を乳鉢で粉砕した後、その粉末をジニトロジアミン白金水溶液に浸漬・攪拌して１２０℃蒸発・乾固した。粉末に対し白金が５質量％であった。
（５）さらに、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。再び乳鉢で粉砕した。
（６）得られたＰｔ／パイロクロア型Ｃｅ２Ｚｒ２Ｏ７／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、白金の触媒金属粒子の平均粒径が３ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、７５度であった。また、前記ペレットを用いて比抵抗を測定したところ、１．５Ω・ｃｍであった。
（７）こうして得られたＰｔ／パイロクロア型Ｃｅ２Ｚｒ２Ｏ７／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、Ｐｔ（５質量％）／パイロクロア型Ｃｅ２Ｚｒ２Ｏ（２０質量％）／カーボンブラック（９５質量％）の触媒インクを作成した。
（８）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（９）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．３ｍｇ／ｃｍ２、パイロクロア型Ｃｅ２Ｚｒ２Ｏが１．２ｍｇ／ｃｍ２であった。
（１０）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（１１）ＭＥＡをセルに組み付け、性能評価した。 (1) A predetermined amount of diammonium cerium nitrate and zirconium oxynitrate were dissolved in pure water and stirred for 2 hours.
(2) Moisture was evaporated at 120 ° C. and then vacuum dried. Then, it was fired in an air firing furnace at 350 ° C. for 5 hours.
(3) The mixture was held at 900 ° C. for 2 hours in a reducing gas (H 2 , 2%) atmosphere, and then switched to an inert gas (N 2 ) and slowly cooled.
(4) The obtained powder was pulverized in a mortar, and then the powder was immersed in a dinitrodiamine platinum aqueous solution and stirred to evaporate and dry at 120 ° C. Platinum was 5% by mass with respect to the powder.
(5) Further, after pulverizing in a mortar, it was calcined at 500 ° C. for 2 hours in an atmospheric calcining furnace. It was crushed again in a mortar.
(6) When the obtained Pt / pyrochlor type Ce 2 Zr 2 O 7 / carbon black powder was observed with a transmission electron microscope, the average particle size of the platinum catalyst metal particles was 3 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 75 degrees. Moreover, when the specific resistance was measured using the pellet, it was 1.5Ω · cm.
(7) The Pt / pyrochroma type Ce 2 Zr 2 O 7 / carbon black thus obtained is mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount (Nafion / Carbon = 1). A catalyst ink of 0.0% by mass, Pt (5% by mass) / pyrochroma type Ce 2 Zr 2 O (20% by mass) / carbon black (95% by mass) was prepared.
(8) The above catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ).
It was used as an electrode film.
(9) the electrode film was analyzed by ICP and total dissolved, 0.3 mg / cm 2 as Pt, pyrochlore Ce 2 Zr 2 O was 1.2 mg / cm 2.
(10) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) was performed on the polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(11) MEA was assembled in the cell and the performance was evaluated.
（２）１２０℃で、水分を蒸発させた後、真空乾燥した。その後、大気焼成炉にて３５０℃で、５時間焼成した。
（３）還元ガス（Ｈ２、２％）雰囲気中９００℃で２時間保持、その後不活性ガス（Ｎ２）に切替えて徐冷した。
（４）得られた粉末を乳鉢で粉砕した後、その粉末をジニトロジアミン白金水溶液に浸漬・攪拌して１２０℃蒸発・乾固した。粉末に対し白金が５質量％であった。
（５）さらに、乳鉢で粉砕した後、大気焼成炉で５００℃、２時間焼成した。再び乳鉢で粉砕した。
（６）得られたＰｔ／パイロクロア型Ｃｅ２Ｚｒ２Ｏ７／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、白金の触媒金属粒子の平均粒径が３ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、７５度であった。また、前記ペレットを用いて比抵抗を測定したところ、１．５Ω・ｃｍであった。
（７）こうして得られたＰｔ／パイロクロア型Ｃｅ２Ｚｒ２Ｏ７／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、Ｐｔ（５質量％）／パイロクロア型Ｃｅ２Ｚｒ２Ｏ（２０質量％）／カーボンブラック（９５質量％）の触媒インクを作成した。
（８）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（９）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．３ｍｇ／ｃｍ２、パイロクロア型Ｃｅ２Ｚｒ２Ｏが１．２ｍｇ／ｃｍ２であった。
（１０）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（１１）ＭＥＡをセルに組み付け、性能評価した。 (1) A predetermined amount of diammonium cerium nitrate and zirconium oxynitrate were dissolved in pure water and stirred for 2 hours.
(2) Moisture was evaporated at 120 ° C. and then vacuum dried. Then, it was fired in an air firing furnace at 350 ° C. for 5 hours.
(3) The mixture was held at 900 ° C. for 2 hours in a reducing gas (H 2 , 2%) atmosphere, and then switched to an inert gas (N 2 ) and slowly cooled.
(4) The obtained powder was pulverized in a mortar, and then the powder was immersed in a dinitrodiamine platinum aqueous solution and stirred to evaporate and dry at 120 ° C. Platinum was 5% by mass with respect to the powder.
(5) Further, after pulverizing in a mortar, it was calcined at 500 ° C. for 2 hours in an atmospheric calcining furnace. It was crushed again in a mortar.
(6) When the obtained Pt / pyrochlor type Ce 2 Zr 2 O 7 / carbon black powder was observed with a transmission electron microscope, the average particle size of the platinum catalyst metal particles was 3 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 75 degrees. Moreover, when the specific resistance was measured using the pellet, it was 1.5Ω · cm.
(7) The Pt / pyrochroma type Ce 2 Zr 2 O 7 / carbon black thus obtained is mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount (Nafion / Carbon = 1). A catalyst ink of 0.0% by mass, Pt (5% by mass) / pyrochroma type Ce 2 Zr 2 O (20% by mass) / carbon black (95% by mass) was prepared.
(8) The above catalyst ink was cast on a Teflon (registered trademark) resin film (
It was used as an electrode film.
(9) the electrode film was analyzed by ICP and total dissolved, 0.3 mg / cm 2 as Pt, pyrochlore Ce 2 Zr 2 O was 1.2 mg / cm 2.
(10) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) was performed on the polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(11) MEA was assembled in the cell and the performance was evaluated.
（比較例３）
比較例３は、フッ素シラン処理（０．１質量％）／Ｐｔ（５質量％）／カーボンブラック（９４．９質量％）とした以外は、比較例１と同様にしてＭＥＡを作成し、ＭＥＡをセルに組み付け、性能評価した。 (Comparative Example 3)
In Comparative Example 3, MEA was prepared in the same manner as in Comparative Example 1 except that it was treated with fluorine silane (0.1% by mass) / Pt (5% by mass) / carbon black (94.9% by mass). Was assembled into the cell and the performance was evaluated.
比較例３は、フッ素シラン処理（０．１質量％）／Ｐｔ（５質量％）／カーボンブラック（９４．９質量％）とした以外は、比較例１と同様にしてＭＥＡを作成し、ＭＥＡをセルに組み付け、性能評価した。 (Comparative Example 3)
In Comparative Example 3, MEA was prepared in the same manner as in Comparative Example 1 except that it was treated with fluorine silane (0.1% by mass) / Pt (5% by mass) / carbon black (94.9% by mass). Was assembled into the cell and the performance was evaluated.
（１）まず、攪拌しながら、エタノールにトリデカフルオロオクチルトリエトキシシラン（Ｄｙｎａｓｙｌａｎ Ｆ８２６１、ＥＶＯＮＩＫ社製）を所定量加え、そのまま０．５時間保持した。次に、比較例１で得られたＰｔ／カーボンブラックの粉末を所定量加え、そのまま２時間保持した。その後、ろ過、水洗を３回繰り返し、８０℃で５時間乾燥した。
（２）得られたフッ素シラン処理／Ｐｔ／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、白金の触媒金属粒子の平均粒径が４ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、１５０度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．８Ω・ｃｍであった。
（３）こうして得られたフッ素シラン処理／Ｐｔ／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、フッ素シラン処理（０．１質量％）／Ｐｔ（５質量％）／カーボンブラック（９４．９質量％）の触媒インクを作成した。
（４）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（５）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．３ｍｇ／ｃｍ２であった。
（６）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（７）ＭＥＡをセルに組み付け、性能評価した。 (1) First, while stirring, a predetermined amount of tridecafluorooctyltriethoxysilane (Dynasilan F861, manufactured by EVONIK) was added to ethanol, and the mixture was maintained as it was for 0.5 hours. Next, a predetermined amount of the Pt / carbon black powder obtained in Comparative Example 1 was added, and the mixture was kept as it was for 2 hours. Then, filtration and washing with water were repeated 3 times, and the mixture was dried at 80 ° C. for 5 hours.
(2) When the obtained fluorine silane treatment / Pt / carbon black powder was observed with a transmission electron microscope, the average particle size of the platinum catalyst metal particles was 4 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 150 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.8Ω · cm.
(3) The fluorine silane treatment / Pt / carbon black thus obtained was mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount (Nafion / Carbon = 1.0% by mass). A fluorosilane-treated (0.1% by mass) / Pt (5% by mass) / carbon black (94.9% by mass) catalyst ink was prepared.
(4) The catalyst ink was cast on a Teflon (registered trademark) resin film (thickness 6 mil), dried, and cut into 25 (cm 2 ).
It was used as an electrode film.
(5) When the electrode film was completely dissolved and ICP analyzed, it was 0.3 mg / cm 2 as Pt.
(6) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) to a polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(7) MEA was assembled in the cell and the performance was evaluated.
（２）得られたフッ素シラン処理／Ｐｔ／カーボンブラックの粉末を、透過型電子顕微鏡にて観察したところ、白金の触媒金属粒子の平均粒径が４ｎｍであった。次に、得られた粉末を、プレス機を用いて直径２０ｍｍ×厚さ５ｍｍのペレットを作製し、液滴法にて水との接触角で撥水度を測定した。この接触角は、１５０度であった。また、前記ペレットを用いて比抵抗を測定したところ、０．８Ω・ｃｍであった。
（３）こうして得られたフッ素シラン処理／Ｐｔ／カーボンブラックを、イオン交換水、アイオノマー電解質溶液（Ｎａｆｉｏｎ Ｄ５２０）、エタノール、ポリエチレングリコールに所定量混合して（Ｎａｆｉｏｎ／Ｃａｒｂｏｎ＝１．０質量％、フッ素シラン処理（０．１質量％）／Ｐｔ（５質量％）／カーボンブラック（９４．９質量％）の触媒インクを作成した。
（４）上記触媒インクをテフロン（登録商標）樹脂膜にキャスト（膜厚６ｍｉｌ）して、乾燥し、２５（ｃｍ２）に切り出し、
電極膜とした。
（５）前記電極膜を、全溶解してＩＣＰ分析したところ、Ｐｔとして０．３ｍｇ／ｃｍ２であった。
（６）得られた前記カソード電極膜と、アノード電極を比較例１に記載の市販の触媒からなる電極膜とを用いて、高分子固体電解質膜（ＮａｆｉｏｎＮＲ２１１、ｔ=２５μｍ）に熱圧着（１５０℃）してＭＥＡを作成した。
（７）ＭＥＡをセルに組み付け、性能評価した。 (1) First, while stirring, a predetermined amount of tridecafluorooctyltriethoxysilane (Dynasilan F861, manufactured by EVONIK) was added to ethanol, and the mixture was maintained as it was for 0.5 hours. Next, a predetermined amount of the Pt / carbon black powder obtained in Comparative Example 1 was added, and the mixture was kept as it was for 2 hours. Then, filtration and washing with water were repeated 3 times, and the mixture was dried at 80 ° C. for 5 hours.
(2) When the obtained fluorine silane treatment / Pt / carbon black powder was observed with a transmission electron microscope, the average particle size of the platinum catalyst metal particles was 4 nm. Next, the obtained powder was prepared into pellets having a diameter of 20 mm and a thickness of 5 mm using a press machine, and the water repellency was measured by the contact angle with water by the sessile drop method. This contact angle was 150 degrees. Moreover, when the specific resistance was measured using the pellet, it was 0.8Ω · cm.
(3) The fluorine silane treatment / Pt / carbon black thus obtained was mixed with ion-exchanged water, an ionomer electrolyte solution (Nafion D520), ethanol, and polyethylene glycol in a predetermined amount (Nafion / Carbon = 1.0% by mass). A fluorosilane-treated (0.1% by mass) / Pt (5% by mass) / carbon black (94.9% by mass) catalyst ink was prepared.
(4) The catalyst ink was cast on a Teflon (registered trademark) resin film (
It was used as an electrode film.
(5) When the electrode film was completely dissolved and ICP analyzed, it was 0.3 mg / cm 2 as Pt.
(6) Using the obtained cathode electrode membrane and the anode electrode using the electrode membrane made of the commercially available catalyst described in Comparative Example 1, thermocompression bonding (150) to a polymer solid electrolyte membrane (NafionNR211, t = 25 μm). ℃) to prepare MEA.
(7) MEA was assembled in the cell and the performance was evaluated.
［発電性能評価試験］
電極面積２５ｃｍ２の単セル（ＪＡＲＩ標準セル、（財）日本自動車研究所）にて下記の発電性能評価試験を行った。結果を表１の「発電性能」に示す。
「ガス流量」アノード：Ｈ２ ５００ＮｍＬ／ｍｉｎ
カソード：空気 １０００ＮｍＬ／ｍｉｎ
「加湿温度」アノード露点（相対湿度）：７７℃（ＲＨ８８％）
カソード露点（相対湿度）：６０℃（ＲＨ４２％）
「設定圧力」常圧
「セル温度」８０℃ [Power generation performance evaluation test]
The following power generation performance evaluation test was conducted on a single cell (JARI standard cell, Japan Automobile Research Institute) with an electrode area of 25 cm 2 . The results are shown in "Power Generation Performance" in Table 1.
"Gas flow rate" anode:H 2 500NmL / min
Cathode: Air 1000 NmL / min
"Humidification temperature" Anode dew point (relative humidity): 77 ° C (RH88%)
Cathode dew point (relative humidity): 60 ° C (RH42%)
"Set pressure" Normal pressure "Cell temperature" 80 ° C
電極面積２５ｃｍ２の単セル（ＪＡＲＩ標準セル、（財）日本自動車研究所）にて下記の発電性能評価試験を行った。結果を表１の「発電性能」に示す。
「ガス流量」アノード：Ｈ２ ５００ＮｍＬ／ｍｉｎ
カソード：空気 １０００ＮｍＬ／ｍｉｎ
「加湿温度」アノード露点（相対湿度）：７７℃（ＲＨ８８％）
カソード露点（相対湿度）：６０℃（ＲＨ４２％）
「設定圧力」常圧
「セル温度」８０℃ [Power generation performance evaluation test]
The following power generation performance evaluation test was conducted on a single cell (JARI standard cell, Japan Automobile Research Institute) with an electrode area of 25 cm 2 . The results are shown in "Power Generation Performance" in Table 1.
"Gas flow rate" anode:
Cathode: Air 1000 NmL / min
"Humidification temperature" Anode dew point (relative humidity): 77 ° C (RH88%)
Cathode dew point (relative humidity): 60 ° C (RH42%)
"Set pressure" Normal pressure "Cell temperature" 80 ° C
［電気化学的有効表面積（ＥＣＡ）試験］
「ガス流量」アノード：Ｈ２ ２００ＮｍＬ／ｍｉｎ
カソード：Ｎ２ ２００→０ＮｍＬ／ｍｉｎ（測定前にＮ２窒素を遮断）
「加湿温度」アノード露点（相対湿度）：８０℃（ＲＨ１００％）
カソード露点（相対湿度）：８０℃（ＲＨ１００％）
「設定圧力」常圧
「セル温度」８０℃
「測定条件」窒素遮断後に０．０５Ｖ～０．９Ｖの間を５０ｍＶ／秒で、５回走査する。 [Electrochemical effective surface area (ECA) test]
"Gas flow rate" Anode: H 2 200 NmL / min
Cathode: N 2 200 → 0 NmL / min (N 2 nitrogen is blocked before measurement)
"Humidification temperature" Anode dew point (relative humidity): 80 ° C (RH100%)
Cathode dew point (relative humidity): 80 ° C (RH100%)
"Set pressure" Normal pressure "Cell temperature" 80 ° C
"Measurement conditions" After nitrogen blocking, scanning is performed 5 times at 50 mV / sec between 0.05 V and 0.9 V.
「ガス流量」アノード：Ｈ２ ２００ＮｍＬ／ｍｉｎ
カソード：Ｎ２ ２００→０ＮｍＬ／ｍｉｎ（測定前にＮ２窒素を遮断）
「加湿温度」アノード露点（相対湿度）：８０℃（ＲＨ１００％）
カソード露点（相対湿度）：８０℃（ＲＨ１００％）
「設定圧力」常圧
「セル温度」８０℃
「測定条件」窒素遮断後に０．０５Ｖ～０．９Ｖの間を５０ｍＶ／秒で、５回走査する。 [Electrochemical effective surface area (ECA) test]
"Gas flow rate" Anode: H 2 200 NmL / min
Cathode: N 2 200 → 0 NmL / min (N 2 nitrogen is blocked before measurement)
"Humidification temperature" Anode dew point (relative humidity): 80 ° C (RH100%)
Cathode dew point (relative humidity): 80 ° C (RH100%)
"Set pressure" Normal pressure "Cell temperature" 80 ° C
"Measurement conditions" After nitrogen blocking, scanning is performed 5 times at 50 mV / sec between 0.05 V and 0.9 V.
［耐久評価（電位サイクル試験）］
電気化学的有効表面積（ＥＣＡ）試験における触媒活性の半減期を確認するべく、以下の条件により耐久評価を行った。
「ガス流量」アノード：Ｈ２ ２００ＮｍＬ／ｍｉｎ
カソード：Ｎ２ ８００ＮｍＬ／ｍｉｎ
「セル温度」８０℃
「電位サイクル」電位 １．０Ｖ ⇔ １．５Ｖ
サイクル間隔 ２秒／サイクル
電気化学的有効表面積（ＥＣＡ）試験および耐久評価の結果に基づき、ＥＣＡサイクル数の半減期について、表１の「耐久性能」に示す。 [Durability evaluation (potential cycle test)]
In order to confirm the half-life of catalytic activity in the electrochemical effective surface area (ECA) test, durability evaluation was performed under the following conditions.
"Gas flow rate" Anode: H 2 200 NmL / min
Cathode: N 2 800 NmL / min
"Cell temperature" 80 ° C
"Potential cycle" potential 1.0V ⇔ 1.5V
Cycle interval 2 seconds / cycle Based on the results of the electrochemical effective surface area (ECA) test and durability evaluation, the half-life of the number of ECA cycles is shown in "Durability Performance" in Table 1.
電気化学的有効表面積（ＥＣＡ）試験における触媒活性の半減期を確認するべく、以下の条件により耐久評価を行った。
「ガス流量」アノード：Ｈ２ ２００ＮｍＬ／ｍｉｎ
カソード：Ｎ２ ８００ＮｍＬ／ｍｉｎ
「セル温度」８０℃
「電位サイクル」電位 １．０Ｖ ⇔ １．５Ｖ
サイクル間隔 ２秒／サイクル
電気化学的有効表面積（ＥＣＡ）試験および耐久評価の結果に基づき、ＥＣＡサイクル数の半減期について、表１の「耐久性能」に示す。 [Durability evaluation (potential cycle test)]
In order to confirm the half-life of catalytic activity in the electrochemical effective surface area (ECA) test, durability evaluation was performed under the following conditions.
"Gas flow rate" Anode: H 2 200 NmL / min
Cathode: N 2 800 NmL / min
"Cell temperature" 80 ° C
"Potential cycle" potential 1.0V ⇔ 1.5V
表１の結果より、本発明の触媒担持導電体の表面に、突起状を有する導電性複合金属酸化物が担持された電極を用いた燃料電池は、導電性、撥水性および／また酸素吸放出体は、通常の酸素吸放出体またはフッ素系処理からなる電極を用いた比較例２および比較例３と比べても、発電性能および耐久性能において優れていることが分る。さらに、本発明のコアシェル型を兼ねて用いれば、白金使用量を低減できることが分る。
From the results in Table 1, the fuel cell using the electrode in which the conductive composite metal oxide having a protrusion shape is supported on the surface of the catalyst-supporting conductor of the present invention is conductive, water-repellent, and / or absorbs and releases oxygen. It can be seen that the body is superior in power generation performance and durability performance as compared with Comparative Example 2 and Comparative Example 3 using an electrode made of a normal oxygen absorber or fluorine-based treatment. Furthermore, it can be seen that the amount of platinum used can be reduced if the core-shell type of the present invention is also used.
１：触媒金属担持体
２：突起状を有する導電性複合金属酸化物
３：触媒金属粒子
４：アイオノマー（高分子固体電解質）
５：コア層
６：シェル層 1: Catalyst metal carrier 2: Conductive composite metal oxide having protrusions 3: Catalyst metal particles 4: Ionomer (polymer solid electrolyte)
5: Core layer 6: Shell layer
２：突起状を有する導電性複合金属酸化物
３：触媒金属粒子
４：アイオノマー（高分子固体電解質）
５：コア層
６：シェル層 1: Catalyst metal carrier 2: Conductive composite metal oxide having protrusions 3: Catalyst metal particles 4: Ionomer (polymer solid electrolyte)
5: Core layer 6: Shell layer
Claims (17)
- 触媒担持導電体と、高分子電解質とからなる触媒層を有し、
前記触媒担持導電体の表面が、突起を有する導電性複合金属酸化物で覆われ、
前記導電性複合金属酸化物に、触媒金属粒子が担持されている、燃料電池用カソード電極。 It has a catalyst layer composed of a catalyst-supported conductor and a polymer electrolyte.
The surface of the catalyst-supported conductor is covered with a conductive composite metal oxide having protrusions,
A cathode electrode for a fuel cell in which catalyst metal particles are supported on the conductive composite metal oxide. - 前記導電性複合金属酸化物の前記突起の高さが、５ｎｍ～１５ｎｍである、請求項１に記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to claim 1, wherein the height of the protrusion of the conductive composite metal oxide is 5 nm to 15 nm.
- 前記導電性複合金属酸化物が、水との接触角で１４０度以上の撥水性を有する、請求項１または２に記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to claim 1 or 2, wherein the conductive composite metal oxide has water repellency of 140 degrees or more at a contact angle with water.
- 前記導電性複合金属酸化物で覆われた前記触媒担持導電体が、０．２Ω・ｃｍ以下の比抵抗を有する、請求項１～３のいずれかに記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to any one of claims 1 to 3, wherein the catalyst-supporting conductor covered with the conductive composite metal oxide has a specific resistance of 0.2 Ω · cm or less.
- 前記導電性複合金属酸化物が、酸素吸放出体である、請求項１～４のいずれかに記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to any one of claims 1 to 4, wherein the conductive composite metal oxide is an oxygen absorber.
- 前記導電性複合金属酸化物が、ｐ型半導体である、請求項１～５のいずれかに記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to any one of claims 1 to 5, wherein the conductive composite metal oxide is a p-type semiconductor.
- 前記導電性複合金属酸化物が、Ｓｎ２Ｍ２Ｏ７（Ｍ＝Ｔａおよび／またはＮｂ）からなるパイロクロア構造を有する、請求項１～６のいずれかに記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to any one of claims 1 to 6, wherein the conductive composite metal oxide has a pyrochlore structure composed of Sn 2 M 2 O 7 (M = Ta and / or Nb).
- 前記導電性複合金属酸化物が、ＴａドープＳｎＯ２（０．０１質量％≦Ｔａ≦１．０質量％）を含む、請求項１～４のいずれかに記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to any one of claims 1 to 4, wherein the conductive composite metal oxide contains Ta-doped SnO 2 (0.01% by mass ≤ Ta ≤ 1.0% by mass).
- 前記触媒金属粒子が、Ｐｔのシェル層からなるコアシェル構造を有する、請求項１～８のいずれかに記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to any one of claims 1 to 8, wherein the catalyst metal particles have a core-shell structure composed of a Pt shell layer.
- 前記コアシェル構造のコア層が、Ｐｄと、Ｐｔ、ＲｕおよびＣｏの少なくとも一つから選ばれてなる合金からなる、請求項９に記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to claim 9, wherein the core layer of the core-shell structure is made of Pd and an alloy selected from at least one of Pt, Ru and Co.
- 前記触媒担持導電体が、導電性カーボン、グラファイト、グラフェンおよびカーボンアロイから選ばれる少なくとも一つからなる、請求項１～１０のいずれかに記載の燃料電池用カソード電極。 The cathode electrode for a fuel cell according to any one of claims 1 to 10, wherein the catalyst-supporting conductor comprises at least one selected from conductive carbon, graphite, graphene and carbon alloy.
- 請求項１～１１のいずれかに記載の燃料電池用カソード電極の製造方法であって、
前記触媒担持導電体の懸濁液に、塩化スズ（II）および塩化タンタル（V）を加え、ｐＨ１．５～２．０に制御して前記導電性複合金属酸化物を得る工程を含む、燃料電池用カソード電極の製造方法。 The method for manufacturing a cathode electrode for a fuel cell according to any one of claims 1 to 11.
A fuel comprising a step of adding tin (II) chloride and tantalum chloride (V) to the suspension of the catalyst-supported conductor and controlling the pH to 1.5 to 2.0 to obtain the conductive composite metal oxide. A method for manufacturing a cathode electrode for a battery. - 前記導電性複合金属酸化物で被覆された前記触媒担持導電体の懸濁液に、コア層を構成する触媒の金属塩を加えたものを、４０℃～８０℃に加温して触媒金属として還元する第１還元工程を含み、
前記第１還元工程により、前記触媒担持導電体の表面を被覆する突起状の前記導電性複合金属酸化物の表面に、前記触媒金属粒子のコア層が形成される、請求項１２に記載の燃料電池用カソード電極の製造方法。 A suspension of the catalyst-supporting conductor coated with the conductive composite metal oxide to which a metal salt of the catalyst constituting the core layer is added is heated to 40 ° C. to 80 ° C. to obtain a catalyst metal. Including the first reduction step of reduction
The fuel according to claim 12, wherein a core layer of the catalyst metal particles is formed on the surface of the protruding conductive composite metal oxide that covers the surface of the catalyst-supporting conductor by the first reduction step. A method for manufacturing a cathode electrode for a battery. - 突起状の前記導電性複合金属酸化物の表面に、前記触媒金属粒子の前記コア層を有する前記触媒担持導電体の懸濁液に、Ｐｔ塩溶液と還元剤とを加えてＰｔを還元する第２還元工程を含み、
前記第２還元工程により、前記触媒金属粒子のＰｔシェル層が形成される、請求項１３に記載の燃料電池用カソード電極の製造方法。 A Pt salt solution and a reducing agent are added to a suspension of the catalyst-supporting conductor having the core layer of the catalyst metal particles on the surface of the projecting conductive composite metal oxide to reduce Pt. Including 2 reduction steps
The method for manufacturing a cathode electrode for a fuel cell according to claim 13, wherein a Pt shell layer of the catalyst metal particles is formed by the second reduction step. - アノード電極と、
請求項１～１１のいずれかに記載のカソード電極と、
前記アノード電極と前記カソード電極との間に配置された高分子電解質膜と、
を有する固体高分子型燃料電池。 Anode electrode and
The cathode electrode according to any one of claims 1 to 11,
A polymer electrolyte membrane arranged between the anode electrode and the cathode electrode,
Solid polymer fuel cell with. - 前記導電性複合金属酸化物が、Ｓｎ２Ｍ２Ｏ７（Ｍ＝Ｔａおよび／またはＮｂ）からなるパイロクロア構造を有する、請求項１５に記載の固体高分子型燃料電池。 The solid polymer fuel cell according to claim 15, wherein the conductive composite metal oxide has a pyrochlore structure composed of Sn 2 M 2 O 7 (M = Ta and / or Nb).
- 前記導電性複合金属酸化物が、ＴａドープＳｎＯ２（０．０１質量％≦Ｔａ≦１．０質量％）を含む、請求項１５に記載の固体高分子型燃料電池。 The solid polymer fuel cell according to claim 15, wherein the conductive composite metal oxide contains Ta-doped SnO 2 (0.01% by mass ≤ Ta ≤ 1.0% by mass).
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| JP2006066255A (en) * | 2004-08-27 | 2006-03-09 | Toyota Motor Corp | Cathode for fuel cell and solid polymer fuel cell including the same |
| JP4857570B2 (en) * | 2005-02-14 | 2012-01-18 | 株式会社日立製作所 | Catalyst structure and production method thereof |
| CA2703990C (en) * | 2007-11-09 | 2014-10-21 | Kyushu University, National University Corporation | Method for producing electrode material for fuel cell, electrode material for fuel cell, and fuel cell using the electrode material for fuel cell |
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| JP2008091264A (en) * | 2006-10-04 | 2008-04-17 | Toyota Motor Corp | Cathode for fuel cell and solid polymer electrolyte fuel cell equipped with this |
| JP2012043612A (en) * | 2010-08-18 | 2012-03-01 | Toppan Printing Co Ltd | Method for manufacturing electrode catalyst layer and solid polymer fuel cell |
| JP2012049075A (en) * | 2010-08-30 | 2012-03-08 | Jx Nippon Oil & Energy Corp | Method of preparing pyrochlore type oxide and method of manufacturing electrode catalyst for fuel cell |
| JP2017157353A (en) * | 2016-02-29 | 2017-09-07 | 国立大学法人山梨大学 | Alloy electrode catalyst and fuel cell using the same |
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| Publication number | Publication date |
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| CN113795332B (en) | 2024-03-15 |
| JP2020191189A (en) | 2020-11-26 |
| CN113795332A (en) | 2021-12-14 |
| JP7203422B2 (en) | 2023-01-13 |
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