JP2008204690A - Solid polymer fuel cell having catalyst layer of anode electrode and catalyst layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polymer fuel cell capable of remarkably suppressing crossover of methanol which is a fuel in a direct methanol fuel cell, and provide a catalyst layer constituting the fuel cell. <P>SOLUTION: This catalyst layer is of an anode electrode containing catalyst carrying carbon and a proton conductive member. The catalyst carrying carbon is made of (1) platinum-ruthenium alloy catalyst carrying carbon, and (2) platinum catalyst carrying carbon and/or alloy catalyst carrying carbon containing platinum (excluding platinum-ruthenium alloy catalyst carrying carbon). In this solid polymer fuel cell, the catalyst layer is used as the catalyst layer on the anode electrode side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a catalyst layer of an anode electrode and a polymer electrolyte fuel cell having the catalyst layer.

  Various studies have been made on solid polymer fuel cells from the viewpoint of achieving lighter weight, higher output density, and the like than other fuel cells. The solid polymer fuel cell has a structure in which an ion conductive polymer electrolyte membrane is used as an electrolyte membrane, a catalyst layer and an electrode base material are arranged in order on both surfaces, and further sandwiched between separators.

In a polymer electrolyte fuel cell, a cation-conducting polymer electrolyte membrane that normally allows cation (H ⁺ ) to permeate is acted on, and generally has a main chain composed of fluorinated alkylene and a sulfonic acid group at the end. Sulfonate highly fluorinated polymers having side chains composed of fluorinated vinyl ethers are used. This type of polymer electrolyte membrane exhibits sufficient ion conductivity for power generation by being impregnated with appropriate moisture.

  A direct methanol fuel cell (DMFC), which is one of solid polymer fuel cells, has a problem of crossover of methanol as a fuel. Methanol crossover is largely caused by cracks present in the catalyst layer. Therefore, in order to solve the problem of methanol crossover, development of a catalyst layer with reduced cracks is underway. For example, Patent Document 1 discloses a method of filling a crack in a catalyst layer by spraying a paste made of catalyst-supporting carbon having small particles with a spray.

However, the catalyst layer disclosed in Patent Document 1 is not dense on the electrolyte membrane side of the catalyst layer, so that the problem of crossover has not yet been solved.
JP 2006-286477 A

  An object of the present invention is to provide a polymer electrolyte fuel cell capable of remarkably suppressing the crossover of methanol as a fuel in a direct methanol fuel cell (DMFC), and a catalyst layer constituting the fuel cell.

  The present inventor has intensively studied in order to solve the above problems. As a result, (1) platinum ruthenium alloy catalyst-supported carbon and (2) platinum catalyst-supported carbon and / or alloy catalyst-supported carbon containing platinum (platinum ruthenium alloy catalyst-supported carbon) as catalyst-supporting carbon constituting the catalyst layer of the anode electrode It was found that the above-mentioned problems can be solved by using together. The present invention has been completed based on such findings.

The present invention provides a catalyst layer and a fuel cell described in the following items 1 to 9.
Item 1. A catalyst layer of an anode electrode containing a catalyst-carrying carbon and a proton conductive member, wherein the catalyst-carrying carbon includes (1) platinum ruthenium alloy catalyst-carrying carbon and (2) platinum catalyst-carrying carbon and / or an alloy containing platinum. A catalyst layer made of catalyst-supported carbon (excluding platinum-ruthenium alloy catalyst-supported carbon).
Item 2. Item 2. The catalyst layer according to Item 1, wherein the catalyst-carrying carbon of (1), the catalyst-carrying carbon of (2), and the proton conductive member are uniformly mixed.
Item 3. Item 1. The catalyst-carrying carbon of (2) serves as a core, and the catalyst-carrying carbon of (1) is arranged around the catalyst-carrying carbon of (2) so as to fill a gap between the catalyst-carrying carbons of (2). The catalyst layer described in 1.
Item 4. Item 2. The catalyst layer according to Item 1, wherein the particle size of the catalyst supported on the carbon of (2) is larger than the particle size of the catalyst supported on the carbon of (1).
Item 5. Item 5. The catalyst layer according to Item 4, wherein the particle size of the catalyst supported on the carbon of (1) is 2 to 4 nm, and the particle size of the catalyst supported on the carbon of (2) is 4 to 6 nm.
Item 6. Item 1. The platinum-ruthenium alloy loading of the catalyst-supporting carbon of (1) is 20 to 80% by weight, and the catalyst-supporting carbon of (2) is 20 to 70% by weight of platinum or an alloy containing platinum. The catalyst layer described.
Item 7. Item 2. The catalyst layer according to Item 1, wherein the compounding ratio of the catalyst-carrying carbon of (1) and the catalyst-carrying carbon of (2) is 0.2 to 5 parts by weight of the latter with respect to 1 part by weight of the former.
Item 8. Item 2. The catalyst layer according to Item 1, wherein the compounding ratio of the catalyst-carrying carbon of (1) and the catalyst-carrying carbon of (2) is 0.3 to 3 parts by weight of the latter with respect to 1 part by weight of the former.
Item 9. Item 9. A polymer electrolyte fuel cell comprising the catalyst layer according to any one of Items 1 to 8.

Catalyst Layer of Anode Electrode The catalyst layer of the present invention contains catalyst-supporting carbon and a proton conductive member. The catalyst-supporting carbon is a mixture of (1) platinum-ruthenium alloy catalyst-supporting carbon and (2) platinum-catalyst-supporting carbon and / or alloy catalyst-supporting carbon containing platinum (excluding platinum-ruthenium alloy catalyst-supporting carbon).

  In the catalyst-carrying carbon (1), a platinum ruthenium alloy catalyst is carried on carbon particles.

  Carbon particles are known, and examples thereof include carbon black, carbon nanotube, and carbon wire. The platinum ruthenium alloy loading ratio of the carbon particles is preferably 20 to 80% by weight, and more preferably 40 to 70% by weight.

  The particle diameter of the catalyst (platinum ruthenium alloy) supported on carbon (1) is preferably 0.5 to 6 nm, and more preferably 2 to 4 nm. The particle diameter is measured, for example, by transmission electron microscopy or diffraction line width analysis (LBA method).

  The primary particle diameter of the catalyst-supporting carbon (1) is preferably 10 to 50 nm, and more preferably 20 to 40 nm. The primary particle diameter of carbon is measured by, for example, transmission electron microscopy.

  The catalyst-carrying carbon (2) has a platinum catalyst and / or an platinum-containing alloy catalyst (excluding a platinum ruthenium alloy catalyst) carried on carbon particles.

  Carbon particles are known, and examples thereof include carbon black, carbon nanotube, and carbon wire. The support ratio of platinum and / or an alloy containing platinum in the carbon particles is preferably 20 to 80% by weight, more preferably 40 to 70% by weight. As an alloy containing platinum, various alloys based on platinum can be widely used. For example, platinum cobalt alloy, platinum iron alloy, platinum chromium alloy, platinum titanium alloy, platinum molybdenum alloy, platinum tungsten alloy, platinum palladium alloy, platinum A nickel alloy, a platinum iridium alloy, etc., and these mixtures are mentioned. The catalyst supported on the carbon particles may be platinum, an alloy containing platinum, or a mixture thereof.

  The particle diameter of the catalyst (platinum or an alloy containing platinum) supported on carbon (2) is preferably larger than the particle diameter of the catalyst supported on carbon (1). For example, the particle size of the catalyst supported on carbon (2) is preferably 0.5 to 10 nm, and more preferably 4 to 6 nm. In particular, the particle diameter of the catalyst supported on the carbon of (1) is preferably 2/3 or less, more preferably 1/2 or less of the particle diameter of the catalyst supported on the carbon of (2).

  The primary particle diameter of the catalyst-supporting carbon (2) is preferably 10 to 50 nm, and more preferably 20 to 40 nm.

  In the catalyst layer of the present invention, the catalyst-carrying carbon (1), the catalyst-carrying carbon (2) and the proton conductive member are preferably mixed uniformly.

  In the catalyst layer of the present invention, the catalyst-carrying carbon of (1) is the core of the catalyst-carrying carbon of (2), and the catalyst-carrying carbon of (2) is filled with the gap between the catalyst-carrying carbons of (2). It is preferable to arrange | position around.

  In the present invention, it is important to use the catalyst-carrying carbon (1) and the catalyst-carrying carbon (2) in combination. The combined ratio of the catalyst-carrying carbon (1) and the catalyst-carrying carbon (2) may be within a range in which the effects of the present invention can be exhibited. For example, the combined ratio of the catalyst-carrying carbon (1) and the catalyst-carrying carbon (2) is usually 0.2-5 parts by weight, preferably 0.3-3 parts by weight with respect to 1 part by weight of the former. Part.

  As the proton conductive member contained in the catalyst layer of the present invention, those known in this field can be widely used, and examples thereof include fluororesins and hydrocarbon resins. As the fluororesin, for example, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), perfluoroethylene (PFA), polyvinylidene fluoride (PVDF) and the like are preferable. These are used individually by 1 type or in mixture of 2 or more types.

  The proportion of the proton conductive member in the catalyst layer is usually 5 to 60% by weight, preferably 10 to 50%, based on the total weight of the catalyst layer, from the viewpoint of ease of catalyst layer formation, power generation performance of the fuel cell, and the like. % By weight. The remainder is (1) catalyst-carrying carbon and (2) catalyst-carrying carbon.

  The film thickness of the catalyst layer is usually 10 to 100 μm, preferably 15 to 30 μm.

Catalyst layer-electrolyte membrane laminate The catalyst layer-electrolyte membrane laminate of the present invention has the anode electrode catalyst layer formed on one surface of the electrolyte membrane and the cathode electrode catalyst layer formed on the other surface. In the catalyst layer-electrolyte membrane laminate, a plurality of anode electrode catalyst layers (preferably a plurality of anode electrode catalyst layers having the same shape) are formed on one side of the electrolyte membrane at regular intervals. A plurality of cathode electrode catalyst layers (preferably a plurality of cathode electrode catalyst layers having the same shape) may be formed on the surface at regular intervals.

  The electrolyte membrane is a known one. The thickness of the electrolyte membrane is usually about 20 to 250 μm, preferably about 20 to 80 μm. Specific examples of the electrolyte membrane include “Nafion” membrane manufactured by DuPont, “Flemion” membrane manufactured by Asahi Glass Co., Ltd., “Aciplex” membrane manufactured by Asahi Kasei Co., Ltd., and the like.

  A well-known thing can be widely used as a catalyst layer of a cathode electrode. The film thickness may be the same as that of the catalyst layer of the anode electrode, and is usually 10 to 100 μm, preferably 15 to 30 μm.

  In the catalyst layer-electrolyte membrane laminate of the present invention, for example, the transfer sheet is arranged so that the catalyst layer surface of the transfer sheet shown below faces the electrolyte membrane surface, and after pressurization, the substrate of the transfer sheet is used as the catalyst layer surface. It is manufactured by peeling from. By repeating this operation twice, a catalyst layer-electrolyte membrane laminate in which the catalyst layer surface is laminated on both surfaces of the electrolyte membrane is produced.

  In consideration of workability, the catalyst layer surface is preferably laminated on both surfaces of the electrolyte membrane at the same time. In this case, for example, the transfer sheet may be disposed so that the catalyst layer surface of the transfer sheet faces both surfaces of the electrolyte membrane, pressurize, and then the substrate of the transfer sheet may be peeled off.

  The pressure level is usually about 0.5 to 20 Mpa, preferably about 0.1 to 10 Mpa, in order to avoid poor transfer. Further, it is preferable to heat the pressure surface during this pressure operation in order to avoid transfer failure. The heating temperature is usually 200 ° C. or lower, preferably about 120 to 200 ° C., in order to avoid damage or modification of the electrolyte membrane.

  Moreover, the catalyst layer-electrolyte membrane laminate of the present invention can be produced by applying the catalyst layer forming paste composition shown below on at least one surface of the electrolyte membrane and drying it. The application and drying conditions may be the same as described above.

Catalyst Layer Forming Paste Composition The catalyst layer forming paste composition of the present invention comprises (A) a catalyst in which (B) a hydrogen ion conductive polymer electrolyte and (C) a solvent are blended in an aqueous dispersion of catalyst-supporting carbon particles. It is a paste composition for layer formation.

  The catalyst-carrying carbon particles of (A) are the above (1) platinum ruthenium alloy catalyst-carrying carbon particles and (2) platinum catalyst-carrying carbon and / or platinum-containing alloy catalyst-carrying carbon particles (excluding platinum ruthenium alloy catalyst-carrying carbon particles). ).

  The aqueous dispersion of catalyst-carrying carbon particles can be obtained by dispersing the catalyst-carrying carbon particles in water. In dispersing the catalyst-carrying carbon particles in water, known methods can be widely used.

  The hydrogen ion conductive polymer electrolyte (B) is known.

  Examples of the hydrogen ion conductive polymer electrolyte include perfluorosulfonic acid fluorine ion exchange resins and hydrocarbon ion exchange resins.

Specific examples of the perfluorosulfonic acid-based fluorine ion exchange resin are selected from the group consisting of, for example, a polymer unit based on tetrafluoroethylene, a sulfonic acid group (—SO ₃ H), and a carboxylic acid group (—COOH). Examples thereof include a copolymer containing a polymer unit based on perfluorovinyl ether having at least one functional group.

  Usually, the hydrogen ion conductive electrolyte (B) is used as an alcohol aqueous solution containing about 5 to 30% by weight of the electrolyte.

  The solid content concentration of the aqueous dispersion of (A) catalyst-supporting carbon particles and (B) the hydrogen ion conductive polymer electrolyte is 9 to 20% by weight, preferably 10 to 13% by weight.

  The blending ratio of the solid content (catalyst-supported carbon) in the component (A) and the solid content (hydrogen ion conductive polymer electrolyte) in the component (B) is 20 to 100 parts by weight for the latter. The amount is about 200 parts by weight, preferably about 30 to 90 parts by weight.

  As the solvent of (C), known solvents can be widely used, and examples thereof include polyhydric alcohols such as t-butanol, 1-butanol, 1-propanol, 2-propanol, 2-butanol, propylene glycol / ethylene glycol and the like. It is done. These solvents are used singly or in combination of two or more.

  The order of mixing the components (A) to (C) is not particularly limited. For example, a paste composition can be prepared by mixing (A) component, (B) component, and (C) component sequentially or simultaneously and dispersing. For mixing, known mixing means can be widely applied.

  The catalyst layer forming paste composition is used for forming a catalyst layer of an anode electrode.

  In forming the catalyst layer of the cathode electrode, catalyst-supporting carbon particles suitable for the catalyst layer of the cathode electrode may be used in place of the catalyst-supporting carbon particles in the catalyst layer forming paste composition.

Catalyst layer-transfer sheet for production of electrolyte membrane laminate The transfer layer for production of catalyst layer-electrolyte membrane laminate of the present invention is obtained by applying the paste composition on a substrate and drying it to form a catalyst layer. is there.

  The catalyst layer may be formed on one surface of the substrate, or may be formed on both surfaces of the substrate.

  In the transfer sheet of the present invention, a plurality of catalyst layers, preferably a plurality of catalyst layers having the same shape, may be formed at regular intervals on one side or both sides of the substrate.

  Examples of the base material include polyimide, polyethylene terephthalate, polyparvanic acid aramid, polyamide (nylon), polysulfone, polyethersulfone, polyphenylene sulfide, polyether etherketone, polyetherimide, polyarylate, polyethylene naphthalate, and the like. Mention may be made of molecular films.

  Further, heat resistance of ethylene tetrafluoroethylene copolymer (ETFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroperfluoroalkyl vinyl ether copolymer (PFA), polytetrafluoroethylene (PTFE), etc. Fluorine resin can also be used.

  Further, the base material may be paper such as art paper, coated paper, light coated paper, and other non-coated paper such as notebook paper and copy paper, in addition to the polymer film. The base material may be a sheet made of carbon fibers such as carbon cloth and carbon paper.

  The thickness of the substrate is usually about 6 to 100 μm, preferably about 10 to 50 μm, and more preferably about 15 to 30 μm from the viewpoints of handleability and economy.

  Accordingly, the base material is preferably a polymer film that is inexpensive and easily available, and more preferably polyethylene terephthalate.

  The transfer sheet for producing a catalyst layer-electrolyte membrane laminate of the present invention is produced by forming a coating film comprising the paste composition on at least one surface of a substrate.

  In forming a coating film composed of the paste composition on at least one surface of the substrate, the paste composition is applied on the substrate according to a known method so that the formed coating film has a desired layer thickness. It is good to apply to.

  The method for applying the paste composition is not particularly limited. For example, knife coating, bar coating, blade coating, spraying, dip coating, spin coating, roll coating, die coating, curtain coating, screen printing, etc. Applicable.

  A coating film is formed by applying and then drying the paste composition. A drying temperature is about 40-120 degreeC normally, Preferably it is about 75-95 degreeC. Although depending on the drying temperature, the drying time is usually about 5 minutes to 2 hours, preferably about 30 minutes to 1 hour.

Electrode-electrolyte membrane assembly The electrode-electrolyte membrane assembly is produced by placing an electrode substrate on both sides of the catalyst layer-electrolyte membrane laminate produced as described above and applying pressure thereto.

  The electrode base material is well known, and various electrode base materials constituting a fuel electrode and an air electrode can be used.

  The pressure level is usually about 0.1 to 100 Mpa, preferably about 5 to 15 Mpa. It is preferable to heat at the time of this pressurization operation, and heating temperature may be about 120-150 degreeC normally.

Polymer electrolyte fuel cell The polymer electrolyte fuel cell of the present invention is composed of the electrode-electrolyte membrane assembly produced as described above.

  In the present invention, cracks are greatly reduced in the catalyst layer on the anode electrode side, and methanol crossover can be remarkably suppressed in DMFC. Therefore, the polymer electrolyte fuel cell having the catalyst layer can efficiently convert methanol into electric energy, and can achieve high performance of DMFC.

  The present invention will be further clarified by the following examples.

Example 1 (Preparation of catalyst transfer film)
(1) Transfer sheet for manufacturing anode catalyst layer-electrolyte membrane laminate Platinum-ruthenium alloy catalyst-supported carbon (platinum-supported amount: 40 wt%, ruthenium-supported amount: 30 wt%, platinum-ruthenium alloy particle size is 2-4 nm, catalyst-supported carbon Primary particle diameter of 30 nm) and platinum catalyst-supported carbon (platinum supported amount: 66.8 wt%, platinum particle diameter of 4 to 6 nm, catalyst-supported carbon primary particle diameter of 30 nm, TEC10E70TPM manufactured by Tanaka Kikinzoku Kogyo Co., Ltd. ) 5 g of 1-butanol, 5 g of 3-butanol, 5 g of a fluororesin (20 wt% Nafion binder, manufactured by DuPont) and 5 g of water were added to 0.5 g, and these were stirred and mixed with a disperser, whereby the anode catalyst layer A forming paste composition was prepared.

Next, the paste composition was applied to an OPP film (manufactured by Panac, Trefan, thickness 30 μm) so that the weight of platinum ruthenium after drying the catalyst layer was 1.5 mg / cm ^2, and the anode catalyst layer-electrolyte A transfer sheet for producing a film laminate was produced.

(2) Transfer sheet for production of cathode catalyst layer-electrolyte membrane laminate Platinum catalyst-supported carbon (platinum support amount: 45.7 wt%, platinum particle size is 4 to 6 nm, catalyst support carbon primary particle size is 30 nm, Tanaka Kikinzoku By adding 15 g of 1-butanol, 2.5 g of 3-butanol, 5 g of a fluororesin (20 wt% Nafion binder, manufactured by DuPont) and 5 g of water to 2 g of TEC10E50E manufactured by industry, and stirring and mixing them with a disperser A paste composition for forming a cathode catalyst layer was prepared.

Next, the paste composition was applied to a polyester film (Toray, X44, thickness 25 μm) so that the platinum weight after drying the catalyst layer was 1.0 mg / cm ^2, and the cathode catalyst layer-electrolyte layer was laminated. A transfer sheet for body production was prepared.

(3) Catalyst layer-electrolyte membrane laminate The anode catalyst produced in (1) above, wherein a polymer electrolyte membrane (Nafion 117, manufactured by DuPont) was cut to 50 × 50 mm and then cut to 30 × 30 mm on one side of the electrolyte membrane. Layer-electrolyte membrane laminate transfer sheet, the cathode catalyst layer-electrolyte laminate laminate transfer sheet produced in the above (2) cut to 30 × 30 mm on the other side, so that each faced, The catalyst layer-electrolyte of the present invention is formed by hot pressing under conditions of 135 ° C., 5.0 MPa, 150 seconds to form an anode catalyst layer on one side of the electrolyte and a cathode catalyst layer on the other side. A film laminate was prepared. The layer structure at this time is catalyst layer / electrolyte membrane / catalyst layer.

Comparative Example 1
(1) Transfer sheet for manufacturing anode catalyst layer-electrolyte membrane laminate Platinum-ruthenium alloy catalyst-supported carbon (platinum-supported amount: 40 wt%, ruthenium-supported amount: 30 wt%, platinum-ruthenium alloy particle size is 2-4 nm, catalyst-supported carbon The primary particle diameter is 30 nm) and 2.0 g of 1-butanol, 5 g of 3-butanol, 5 g of a fluororesin (20 wt% Nafion binder, manufactured by DuPont) and 5 g of water are added and mixed with a disperser. Thus, a paste composition for forming an anode catalyst layer was prepared.

Next, the paste composition was applied to an OPP film (manufactured by Panac, Trefan, thickness 30 μm) so that the weight of platinum ruthenium after drying the catalyst layer was 1.5 mg / cm ^2, and the anode catalyst layer-electrolyte A transfer sheet for producing a film laminate was produced.

(2) Transfer sheet for production of cathode catalyst layer-electrolyte membrane laminate The transfer sheet for production of cathode catalyst layer-electrolyte membrane laminate obtained in (2) of the above example was used.

(3) Catalyst layer-electrolyte membrane laminate Manufactured in Comparative Example 1 (1) above, in which a polymer electrolyte membrane (Nafion 117, manufactured by DuPont) was cut to 50 × 50 mm and then cut to 30 × 30 mm on one side of the electrolyte membrane. The anode catalyst layer-electrolyte membrane laminate transfer sheet produced on the other side and the cathode catalyst layer-electrolyte membrane laminate transfer sheet produced in Example 1 (2) cut to 30 × 30 mm on the other side face each other. The anode catalyst layer was formed on one surface of the electrolyte and the cathode catalyst layer was formed on the other surface by hot pressing under conditions of 135 ° C., 2.3 MPa, 150 seconds, and compared. A catalyst layer-electrolyte membrane laminate for was prepared. The layer structure at this time is catalyst layer / electrolyte membrane / catalyst layer.

  From the catalyst layer surface micrograph of the catalyst layer-electrolyte membrane laminate obtained in Example 1 and the micrograph of the cross section of the catalyst layer-electrolyte membrane laminate, cracks in the catalyst layer on the anode electrode side are reduced, and It was confirmed that the catalyst layer was densely formed. On the other hand, from the catalyst surface micrograph of the catalyst layer-electrolyte membrane laminate and the micrograph of the cross section of the catalyst layer-electrolyte membrane laminate obtained in Comparative Example 1, there are many cracks in the catalyst layer on the anode electrode side, and the catalyst layer It was confirmed that was not formed densely.

  Moreover, when the distribution of each element which comprises a catalyst layer was measured by the EDX analysis about the catalyst layer of the catalyst layer-electrolyte membrane laminated body obtained in Example 1, each element is mixed uniformly in a catalyst layer. I confirmed that

Performance Evaluation Test The catalyst layer-electrolyte membrane laminates obtained in Example 1 and Comparative Example 1 were each incorporated into a fuel cell, and the respective open circuit voltage (OCV) and maximum power density (P _max ) were measured. The measurement conditions at this time are a cell temperature of 70 ° C. and 1M methanol.

As a result, the open circuit voltage (OCV) of the fuel battery cell incorporating the catalyst layer-electrolyte membrane laminate obtained in Example 1 is 0.748 V, and the maximum output density (P _max ) is 51.9 mW / cm. ² . On the other hand, the open circuit voltage (OCV) of the fuel battery cell incorporating the catalyst layer-electrolyte membrane laminate obtained in Comparative Example 1 is 0.722 V, and the maximum output density (P _max ) is 49.3 mW / cm ^2. Met.

  From the above test results, it is clear that the polymer electrolyte fuel cell having the catalyst layer of the present invention has excellent cell performance.

Claims (9)

A catalyst layer of an anode electrode containing a catalyst-supporting carbon and a proton conductive member,
The catalyst-supported carbon is composed of (1) platinum ruthenium alloy catalyst-supported carbon and (2) platinum catalyst-supported carbon and / or an alloy catalyst-supported carbon containing platinum (excluding platinum ruthenium alloy catalyst-supported carbon).
Catalyst layer.   The catalyst layer according to claim 1, wherein the catalyst-carrying carbon of (1), the catalyst-carrying carbon of (2), and the proton conductive member are uniformly mixed.   The catalyst-carrying carbon of (2) serves as a core, and the catalyst-carrying carbon of (1) is disposed around the catalyst-carrying carbon of (2) so as to fill a gap between the catalyst-carrying carbons of (2). The catalyst layer according to 1.   The catalyst layer according to claim 1, wherein the particle diameter of the catalyst supported on the carbon of (2) is larger than the particle diameter of the catalyst supported on the carbon of (1).   The catalyst layer according to claim 4, wherein the particle diameter of the catalyst supported on carbon of (1) is 2 to 4 nm, and the particle diameter of the catalyst supported on carbon of (2) is 4 to 6 nm. .   The catalyst-supporting carbon of (1) has a platinum ruthenium alloy support of 20 to 80% by weight, and the catalyst-supporting carbon of (2) has a support of platinum or an alloy containing platinum of 20 to 70% by weight. The catalyst layer described in 1.   The catalyst layer according to claim 1, wherein the blending ratio of the catalyst-carrying carbon (1) and the catalyst-carrying carbon (2) is 0.2 to 5 parts by weight with respect to 1 part by weight of the former.   The catalyst layer according to claim 1, wherein the blending ratio of the catalyst-carrying carbon (1) and the catalyst-carrying carbon (2) is 0.3 to 3 parts by weight with respect to 1 part by weight of the former.   A polymer electrolyte fuel cell comprising the catalyst layer according to claim 1.