JP2000173625A - Electrode for fuel cell and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve water repellency of a fuel cell electrode for improving the performance of a fuel cell electrode. SOLUTION: In this fuel cell electrode, having a catalyst layer containing a solid polymer electrolyte 42 and catalyst particles 41, a surface and portions corresponding to micro-pores 43 of the catalyst layer have a porous resin. For example, after the solution of a resin in a solvent (a) is stored in the catalyst layer which contains the solid polymer electrolyte 42 and the catalyst particles 41, the catalyst layer is immersed in a solvent (b) which is insoluble in the resin but soluble in the solvent (a) to form the fuel cell electrode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel cell electrode and a method for producing the same.

[0002]

2. Description of the Related Art A solid polymer electrolyte fuel cell uses an ion exchange membrane as an electrolyte, and has an anode and a cathode each having a catalyst layer and a gas diffusion layer containing a conductive porous material on both sides of the ion exchange membrane. This device is configured by joining electrodes and supplies hydrogen to the anode and oxygen to the cathode to generate power by an electrochemical reaction. The electrochemical reaction occurring at each electrode is shown below.

Anode: H ₂ → 2H ⁺ + 2e Cathode: 1 / 2O ₂ + 2H ⁺ + 2e → H ₂ O Total reaction: H ₂ + 1 / 2O ₂ → H ₂ O As is clear from this reaction formula, the reaction of each electrode is Proceeds only at the three-phase interface where the transfer of the gas (hydrogen or oxygen), proton (H ⁺ ), and electron (e) as the active material can be performed simultaneously.

As shown in FIG. 5, the electrode of the fuel cell has a catalyst particle 51 and a solid polymer electrolyte 52 which are mixed and distributed three-dimensionally and have a plurality of pores 54 formed therein. And a gas diffusion layer 58 containing a conductive porous body 57.

The gas diffusion layer 58 is provided with a certain space in the surface layer of the catalyst layer 56 to secure a flow path for transporting oxygen and hydrogen, which are active materials supplied from outside the battery, to the surface layer of the catalyst layer 56.
Also, it has a role of securing a flow path for discharging water generated in the catalyst layer of the cathode from the surface layer of the catalyst layer 56 to the outside of the battery system.

On the other hand, in the catalyst layer 56, the catalyst particles 51 form an electron conduction channel, the solid electrolyte 52 forms a proton conduction channel, and the pores 54 transfer oxygen or hydrogen carried to the surface of the catalyst layer 56 to the electrode. A supply / discharge channel is formed to supply water to a deep part and discharge water generated at a deep part of the electrode (cathode) to a surface layer of the electrode. Then, these three channels are three-dimensionally spread in the catalyst layer 56, and a myriad of three-phase interfaces capable of simultaneously transmitting and receiving gas, protons (H ⁺ ) and electrons (e) are formed. Offers a place.

In FIG. 5, reference numeral 53 denotes PTFE (polytetrafluoroethylene) particles, which serve to impart water repellency to the inside of the pores 54 of the catalyst layer 56 and to the surface layer.
Further, 55 indicates an ion exchange membrane. Here, since the ion exchange membrane 55 serving as an electrolyte shows good proton conductivity in a water-containing state, it must be operated while keeping the inside of the battery in a wet state. Therefore, the ion exchange membrane 55
The moisture of the ion exchange membrane is controlled by appropriately humidifying the hydrogen and oxygen supplied to the anode and the cathode so as not to dry.

[0008]

In a solid polymer electrolyte fuel cell, the pores in the catalyst layer form a supply channel for oxygen or hydrogen. Water accumulates in the surface layer of the catalyst layer, and the water blocks the gas supply inlet of the pores, hinders the supply of gas into the pores, or accumulates water in the pores. In some cases, the supply of the active material to the deep portion is interrupted, the working area actually working is reduced, and the battery performance cannot be sufficiently taken out. For this reason, a suitable water repellency is imparted to the gas diffusion layer and the catalyst layer containing the conductive porous body so that water does not collect.

For imparting water repellency to the conductive porous body, for example, in the case of carbon paper (thickness: 1.5 mm) which is a commonly used sintered body of carbon fiber, the carbon paper is immersed in a PTFE particle dispersion solution. After the PTFE particles are contained, the carbon fiber is coated with PTFE by baking at 350 ° C. for 15 minutes in a nitrogen atmosphere.

On the other hand, the water repellency of the catalyst layer is imparted to the catalyst layer by dispersing a noble metal particle such as platinum on a carbon particle carrier, which is a catalyst particle, in a highly dispersed manner, and a catalyst layer paste comprising a solid polymer electrolyte solution and a solid polymer electrolyte solution. By mixing a PTFE particle dispersion solution into the mixture.

However, at present, the water repellency of the catalyst layer and the conductive porous body is not sufficient. To increase the output of the battery, a high-temperature, humidified gas is supplied to reduce the proton conductivity of the ion exchange membrane. If it were to be improved, water would instead accumulate in the pores of the catalyst layer and in the surface layer, and the supply of active material to the three-phase interface of the catalyst layer, especially to the deep part of the electrode, would be reduced, and the working area that would actually work was reduced, and the battery performance was reduced. There is a problem that can not be pulled out enough. In particular, water is likely to accumulate in the fine pores since water is generated in the cathode due to the reaction.

In order to avoid this, for example, in the case of the catalyst layer, the mixing ratio of the PTFE particle dispersion solution applied at the time of preparation of the catalyst layer is increased to increase the water repellency of the catalyst layer, and water is formed in the pores and in the surface layer. You should make it hard to accumulate, but P
The proportion of the catalyst-supporting carbon, the solid polymer electrolyte and the pores is reduced by the volume increase in the electrode of the TFE particles,
There is a problem that the formation of an electron conduction channel, a proton conduction channel, a supply / discharge channel of oxygen or hydrogen and water as a product is inhibited, and the output of the battery is rather reduced.

Further, it is only necessary to increase the application amount of the PTFE dispersion solution when imparting water repellency to the conductive porous body. However, if the amount is too large, the PTFE particles close the pores of the conductive porous body, and This will hinder gas supply.

In view of the above, an object of the present invention is to improve the water repellency of a fuel cell electrode while preventing the above-mentioned problems from occurring, thereby improving the performance of the fuel cell electrode.

[0015]

Means for Solving the Problems The fuel cell electrode of the first invention of the present application is characterized in that it has a catalyst layer containing a solid polymer electrolyte, catalyst particles and a porous resin.

A fuel cell electrode according to a second aspect of the present invention is a fuel cell electrode having a catalyst layer containing a solid polymer electrolyte and catalyst particles, wherein the catalyst layer has a porous equivalent portion and / or a porous surface. It is characterized by having a resin.

According to a third aspect of the present invention, there is provided a fuel cell electrode comprising a catalyst layer containing a solid polymer electrolyte and catalyst particles, and a gas diffusion layer containing a conductive porous material. And the conductive porous body includes a porous resin.

In this case, the conductive porous body is more preferably made of a carbon material.

Further, in any of the above fuel cell electrodes of the invention, the step of replacing the solvent a in the solution in which the resin is dissolved with the solvent b insoluble in the resin and compatible with the solvent a is performed. It is more preferable to use the porous resin obtained through the above.

Furthermore, in any of the above-mentioned electrodes, it is preferable to use a solid polymer electrolyte having an ion exchange function as the solid polymer electrolyte and a water-repellent electrode having no ion exchange function as the porous resin. good. And as a resin which comprises the said porous resin, a fluororesin is more preferable, and among them, it is preferable to use a polyvinylidene fluoride (PVdF) type resin.

The manufacturing method of the present invention is a method for manufacturing the fuel cell electrode of the present invention, wherein a resin is dissolved in a solvent a in a catalyst layer containing a solid polymer electrolyte and catalyst particles. After the above solution is contained, this is immersed in a solvent b which is insoluble in the resin and compatible with the solvent a.

In this case, when the fuel cell electrode has a structure in which a catalyst layer containing a solid polymer electrolyte and catalyst particles and a conductive porous body are laminated, the catalyst layer and the conductive layer After a solution obtained by dissolving a resin in a solvent a is included in a laminate with a gas diffusion layer containing a porous body, the laminate is dissolved in a solvent b insoluble in the resin and compatible with the solvent a. It is good to manufacture by immersion.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to drawings showing an example of the structure of a fuel cell electrode according to the present invention. Figures 2, 3, 4
FIG. 1 is a schematic diagram showing a structural example of a fuel cell electrode according to the present invention.

As shown in these figures, the catalyst layer comprising the solid polymer electrolyte and the catalyst particles according to the present invention comprises:
Catalyst particles 21, 31, 41 and solid polymer electrolytes 22, 3
2, 42 are mixed with each other and distributed three-dimensionally, and a porous catalyst layer having a plurality of pores 23, 33, 43 formed therein is used as a base material. The catalyst particles form the electron conduction channel, the solid electrolyte forms the proton conduction channel, and the pores form the supply and discharge channels of oxygen or hydrogen and the product water.

The fuel cell electrode shown in FIG. 2 is made of a porous resin 2 having a large number of three-dimensionally communicating holes in the portions corresponding to the pores of the catalyst layer.
The fuel cell electrode shown in FIG. 3 is provided with a porous resin 34 having a large number of three-dimensionally communicating holes on the surface of the catalyst layer, and the fuel cell electrode shown in FIG. The electrode for use is provided with a porous resin 44 having a large number of three-dimensionally communicating holes on the surface corresponding to the pores of the catalyst layer and on the surface, and the catalyst layer and the conductive porous body are provided with the porous resin. .

Since the pores are eliminated by disposing the porous resin in the pores, this portion is called a pore equivalent portion. In the figures, reference numerals 25, 35, and 45 denote ion exchange membranes, and reference numerals 26, 36, and 46 denote carbon electrode substrates made of a sintered body of a porous conductive substrate carbon fiber.
If necessary, PTFE particles can be provided in the catalyst layer as before.

According to the present invention, by disposing a porous resin having no porous ion-exchange function in a portion corresponding to the pores of the catalyst layer and / or the surface layer, the water repellency of the portion corresponding to the pores and / or the surface layer is increased. Become. This prevents water from accumulating in the surface layer of the catalyst layer and covering and closing the pores, and also prevents water from stagnating in the pores. The catalyst layer is supplied without stagnation to the three-phase interface of the layer, and the catalyst layer can be highly activated.

The effect of the present invention can be obtained by arranging the porous resin only in the pores as shown in FIG. 2 or only in the surface layer as shown in FIG. 3, but as shown in FIG. Higher activation can be achieved by arranging a porous resin in the portion corresponding to the pores of the matrix of the layer and in the surface layer.

The porous resin may be disposed on the entire surface of the catalyst layer matrix as shown in these figures, but may be disposed on a part of the surface layer and / or a part of the pores. May be.

The catalyst particles used in the electrode of the present invention include platinum, rhodium, ruthenium, iridium,
Palladium, platinum group metals such as osnium and alloy particles thereof, or catalyst-carrying carbon supporting these catalysts are suitable, and the solid polymer electrolyte is preferably made of an ion-exchange resin, and is composed of perfluorosulfonic acid or styrene. -A divinylbenzene-based sulfonic acid type solid polymer electrolyte is preferred.

Here, the pores of the porous resin are preferably open cells so that the active material can be smoothly supplied and discharged. The average pore diameter is preferably 1 μm or less, more preferably 0.5 μm or less, and the porosity of the effective resin is preferably 45% or more in terms of gas supply and water discharge. . It is preferable to use a solvent extraction method as a method for producing a porous polymer from which dense open cells can be obtained. That is, by replacing the solvent a of the solution in which the resin is dissolved with a solvent b which is insoluble in the resin and compatible with the solvent a, the solvent a in the solution in which the resin is dissolved is extracted, The portion from which the solvent a has been removed becomes pores to obtain a porous resin.

The resins used in the present invention include polyvinyl chloride, polyacrylonitrile, polyethers such as polyethylene oxide and polypropylene oxide, polyacrylonitrile, vinylidene fluoride polymer, polyvinylidene chloride, polymethyl methacrylate, and polymethyl acrylate. , Polyvinyl alcohol, polymethacrylonitrile, polyvinyl acetate, polyvinylpyrrolidone,
Polyethyleneimine, polybutadiene, polystyrene,
Polyisoprene or a derivative thereof alone,
Alternatively, they may be used as a mixture, or a resin obtained by copolymerizing various monomers constituting the above resin may be used. However, a fluororesin having high water repellency, for example, an ethylene trifluoride chloride copolymer ( PCTFE), vinylidene fluoride polymer (PVdF), vinyl fluoride polymer (PV
F) or a fluorine-containing copolymer such as ethylene / tetrafluoroethylene copolymer (ETFE), ethylene / tetrafluoroethylene / propylene hexafluoride copolymer (EPE), or vinylidene fluoride copolymer Or a mixture thereof.

In the preparation of the effective fluororesin by the solvent extraction method, fine and uniform pores are obtained.
PVdF homopolymer, vinylidene fluoride-propylene hexafluoride copolymer (P (VdF-HFP)) or vinylidene fluoride-tetrafluoroethylene copolymer (P (Vd
F-TFP)) and other polyvinylidene fluorides (PVd
F) -based resins are preferred. Among them, a vinylidene fluoride polymer (PVdF) excellent in water repellency or a vinylidene fluoride-propylene hexafluoride copolymer (P (VdF-HFP)) which is soft and easy to handle is preferable.

The solvent a for dissolving the resin may be any solvent capable of dissolving the resin, and may be a carbonate such as dimethylformamide, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dimethyl ether, diethyl ether, or the like. Examples thereof include ethers such as ethyl methyl ether and tetrahydrofuran, dimethylacetamide, 1-methyl-pyrrolidinone, and n-methyl-pyrrolidone.

As the solvent b for extraction, water or a mixed solution of water and alcohol is preferred at a low cost.

In these combinations, polyvinylidene fluoride (PVdF) or P (VdF-HFP)
Is dissolved in n-methylpyrrolidone (NMP) and extracted with water or a mixed solution of water and alcohol,
It is preferable in terms of water repellency, uniformity of pore size, and the like.

The fuel cell electrode of the present invention can be prepared, for example, by forming a catalyst layer paste containing a catalyst-supporting carbon particle, a solid polymer electrolyte solution and, if necessary, a PTFE particle dispersion solution into a polymer film. Film (generally 3 to
30 μm) and then heating and drying, or a conventional catalyst layer, or a catalyst-supporting carbon particle in which a noble metal particle such as platinum is supported on a carbon particle carrier in a highly dispersed state and, if necessary, a PTFE particle dispersion. A conventional method was prepared by forming a catalyst layer paste to which a solution was added onto a polymer film (generally a thickness of 3 to 30 μm), heating and drying, and then applying and impregnating a solid polymer electrolyte solution from above. After a solution obtained by dissolving a resin in a solvent a is contained in the catalyst layer by coating or dipping, the solvent a is replaced with a solvent b insoluble in the resin and compatible with the solvent a. Can be obtained by Alternatively, a paste of the catalyst layer to which the catalyst-supporting carbon particles and the solid polymer electrolyte solution and, if necessary, the PTFE particle dispersion solution are added, is formed on a conductive porous body (generally, a film thickness of 3 to 30 μm). , A conventional electrode prepared by a method of heating and drying, or a catalyst containing a catalyst-supporting carbon particle in which a noble metal particle such as platinum is supported on a carbon particle carrier in a highly dispersed state and, if necessary, a PTFE particle dispersion solution. A conventional electrode manufactured by a method in which a layer paste is formed on a conductive porous body (generally, a film thickness of 3 to 30 μm), dried by heating, and then coated and impregnated with a solid polymer electrolyte solution. Then, after a solution obtained by dissolving the resin in the solvent a is included by coating or dipping, the solvent a is placed in a solvent b insoluble in the resin and compatible with the solvent a. It can be obtained by.

In particular, according to the latter manufacturing method, in a fuel cell electrode provided with a catalyst layer containing a solid polymer electrolyte and catalyst particles and a gas diffusion electrode containing a conductive porous material, Since the conductive porous body contains a porous resin, a fuel cell electrode having high activity can be expected. Further, in this case, if a fluororesin having high water repellency is used, it is not necessary to previously impart water repellency to the conductive porous body, and the porous resin disposed on the conductive porous body plays a role. Carry.

Here, as the conductive porous body, nickel foam, titanium fiber sintered body, or the like can be used, but a porous carbon substrate is preferable in terms of conductivity, weight, etc. Good union etc.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to preferred embodiments.

Example 1 A catalyst layer comprising platinum-supported carbon (Tanaka Kikinzoku, 10V30E: 30 wt% platinum supported on Valcan XC-72) and a solid polymer electrolyte solution (Aldrich, Nafion 5 wt% solution) The paste is applied to a conductive porous carbon sheet (0.5
mm) at 120 ° C. for 1 hour in a nitrogen atmosphere.
A PVdF / NMP solution (PVdF
(Concentration: 15 wt%) in vacuum and then impregnated in water.
The electrode was immersed in the fuel cell for 1 minute to obtain a fuel cell electrode A.

The electrode A has a structure in which effective PVdF resin is disposed in the pores and the surface layer of the catalyst layer, and furthermore, the conductive porous body.

The platinum amount of the electrode A is about 1.0 mg / cm ²
The amount of platinum-carrying carbon during the preparation of the paste was adjusted such that

Further, the electrode A is hot-pressed (140
C.) and bonded to both surfaces of an ion exchange membrane (Dupont, Nafion, film thickness: about 50 μm), and assembled into a single cell of a fuel cell to obtain a cell A.

Example 2 A paste composed of platinum-supported carbon (Tanaka Kikinzoku, 10V30E: platinum supported on Valcan XC-72 at 30 wt%) and a solid polymer electrolyte solution (Aldrich, Nafion, 5 wt% solution) was used. The catalyst layer obtained by coating on a polymer film (PFA) and air-drying for about 1 hour is hot-pressed (140 ° C.)
Was bonded to both surfaces of an ion exchange membrane (manufactured by DuPont, Nafion, film thickness: about 50 μm) to obtain a catalyst layer-ion exchange membrane assembly. Further, a PVdF / NMP solution (PVdF concentration: 15 wt%) was applied to the surface of the catalyst layer with a brush, and then immersed in water for 10 minutes to obtain a catalyst layer B-ion exchange membrane assembly.

The catalyst layer B is mainly composed of a porous PVdF
It has a structure in which a resin is arranged.

The amount of platinum-carrying carbon during the preparation of the paste was adjusted so that the amount of platinum on one side of the catalyst layer B-ion exchange membrane assembly was about 1.0 mg / cm ² .

A conductive porous carbon sheet (0.5
mm) by hot pressing and assembled into a single cell of a fuel cell to obtain a cell B. [Comparative Example 1] Platinum-supporting carbon (Tanaka Kikinzoku, 10 V
30E: 30 wt% platinum in Valcan XC-72
Supported), a solid polymer electrolyte solution (manufactured by Aldrich, Nafion 5 wt% solution) and a PTFE particle dispersion solution (manufactured by Du Pont-Mitsui Fluorochemicals, Teflon 30J)
The electrode paste for fuel cell was coated on a conductive porous carbon electrode substrate (0.5 mm) having water repellency and dried at 120 ° C. for 1 hour in a nitrogen atmosphere.
I got

The platinum amount of the electrode C is about 1.0 mg / cm
So that ² was adjusted supported platinum amount of carbon during the paste producing.

Further, the electrode C is hot-pressed (140
(C), and bonded to both surfaces of an ion exchange membrane (manufactured by DuPont, Nafion, film thickness: about 50 μm), and assembled into a single cell of a fuel cell to obtain a cell C.

[Comparative Example 2] Platinum-supported carbon (Tanaka Kikinzoku, 10V30E: 30 wt% platinum supported on Valcan XC-72), solid polymer electrolyte (Aldrich, Nafion 5 wt% solution) and PTFE particle dispersion solution ( Teflon 3 manufactured by Mitsui Dupont Fluorochemicals
0J) is applied to a polymer film (PFA)
The electrode obtained by coating on the surface and air-drying for about 1 hour was bonded to both surfaces of an ion-exchange membrane (Dupont, Nafion, film thickness of about 50 μm) by hot pressing (140 ° C.) to form a catalyst layer D -An ion exchange membrane assembly was obtained. The amount of platinum on one side of the catalyst layer D-ion exchange membrane assembly was about 1.0 mg / cm.
So that ² was adjusted supported platinum amount of carbon during the paste producing.

A conductive porous carbon sheet (0.5) provided with water repellency to serve as a gas diffusion layer on both surfaces of the joined body.
mm) by hot pressing and assembled into a single cell of a fuel cell to obtain a cell D.

FIG. 1 shows current-voltage characteristics when oxygen and hydrogen were used as supply gases for these cells. The operating conditions were as follows: the supply gas pressure was 2 atm, and each was humidified by bubbling in a closed water tank at 80 ° C. The operating temperature of the cell was set to 75 ° C., and the holding time at the time of measurement at each current value was set to 5 minutes.

FIG. 1 shows that the cells (A and B) according to the present invention have a higher output voltage at each current density than the conventional cells (C and D). In particular, it can be seen that the output of A in which porous PVdF is disposed in the pores of the catalyst layer and the surface layer is higher than that of B. According to the present invention, it is possible to dispose the porous PVdF having high water repellency in the pores of the catalyst layer and / or on the surface layer in order to ensure that the active materials hydrogen and oxygen are deep down to the electrode. This is because supply becomes possible, and the area of the catalyst layer actually acting is larger than that of the conventional catalyst layer. In particular, the cell A in which porous PVdF was arranged in the pores of the catalyst layer and in the surface layer showed good characteristics.

[0055]

According to the fuel cell electrode of the present invention, the electrode area which actually works is larger than the conventional electrode,
High-performance fuel cells can be manufactured. Further, according to the production method of the present invention, an electrode capable of producing a high-performance fuel cell can be produced.

[Brief description of the drawings]

FIG. 1 is a diagram showing current-voltage characteristics of a cell.

FIG. 2 is a schematic view showing the structure of a fuel cell electrode according to the present invention.

FIG. 3 is a schematic view showing the structure of a fuel cell electrode according to the present invention.

FIG. 4 is a schematic view showing the structure of a fuel cell electrode according to the present invention.

FIG. 5 is a schematic view showing the structure of a conventional fuel cell electrode.

[Explanation of symbols]

 21, 31, 41: catalyst particles 22, 32, 42: solid polymer electrolyte 23, 33, 43: pores of catalyst layer 24, 34, 44: porous resin 25, 35, 45: ion exchange membrane 26, 36, 46: carbon electrode substrate

Claims (11)

[Claims] 1. An electrode for a fuel cell, comprising a catalyst layer containing a solid polymer electrolyte, catalyst particles, and a porous resin. 2. A fuel cell electrode having a catalyst layer containing a solid polymer electrolyte and catalyst particles, wherein a porous resin is provided on a portion corresponding to pores and / or on a surface of the catalyst layer. Electrodes for fuel cells. 3. A fuel cell electrode comprising a catalyst layer containing a solid polymer electrolyte and catalyst particles and a gas diffusion layer containing a conductive porous body, wherein the catalyst layer and the conductive porous body are porous. An electrode for a fuel cell, comprising a resin. 4. The fuel cell electrode according to claim 1, wherein said porous resin is a fluororesin. 5. The electrode for a fuel cell according to claim 4, wherein the porous resin is a polyvinylidene fluoride (PVdF) -based resin. 6. The fuel cell electrode according to claim 5, wherein the porous resin is a vinylidene fluoride polymer (PVdF). 7. The fuel cell electrode according to claim 5, wherein the porous resin is a vinylidene fluoride / propylene hexafluoride copolymer (P (VdF-HFP)). 8. A solvent b in which the solvent a of the solution in which the resin is dissolved is insoluble in the resin and compatible with the solvent a.
The method for producing a porous resin according to any one of claims 1 to 7, further comprising a step of substituting the porous resin. 9. The fuel cell electrode according to claim 3, wherein the conductive porous body is made of a carbon material. 10. A catalyst layer comprising a solid polymer electrolyte and catalyst particles, containing a solution in which a resin is dissolved in a solvent a, wherein the solution is insoluble in the resin and compatible with the solvent a. 10. The method for producing an electrode for a fuel cell according to claim 1, wherein the electrode is immersed in a certain solvent b. 11. A fuel cell electrode comprising a stacked body of a catalyst layer and a gas diffusion layer containing a conductive porous body contains a solution obtained by dissolving a resin in a solvent a, and then becomes insoluble in the resin. A method for producing an electrode for a fuel cell, characterized by immersing this in a solvent (b) compatible with the solvent (a).