JP2007217803A - Carbon fiber or method for producing the same, and electrode of solid polymer type fuel cell and solid polymer type fuel cell by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a carbon fiber capable of producing the carbon fiber having a high water content-holding function and the carbon fiber having a wide surface area, and an electrode of a solid polymer type fuel cell by using the carbon fiber produced by such the method. <P>SOLUTION: This method for producing the carbon fiber is provided by comprising a process of oxidatively polymerizing a compound having an aromatic ring while irradiating ultrasonic wave to form a fibril-formed polymer, and a process of calcinating the fibril-formed polymer to produce the carbon fiber having a three-dimensional continuous structure. The electrode of the solid polymer type fuel cell is provided by consisting of a porous supporting material, the carbon fiber produced by the above method and arranged on the above porous supporting material and a metal catalyst carried by the carbon fiber. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a carbon fiber and a method for producing the same, an electrode for a polymer electrolyte fuel cell using the carbon fiber, and a polymer electrolyte fuel cell including the electrode, and in particular, the density can be easily changed. And it is related with the manufacturing method of carbon fiber which can manufacture carbon fiber which has a high moisture retention function.

  In recent years, fuel cells have attracted attention as a battery having high power generation efficiency and a low environmental load, and extensive research and development has been conducted. Among these fuel cells, solid polymer fuel cells with high output density and low operating temperature are easier to reduce in size and cost than other types of fuel cells. It is expected to be widely used as a power source, distributed power generation system, and household cogeneration system.

  In general, in a polymer electrolyte fuel cell, a pair of electrodes are arranged with a solid polymer electrolyte membrane made of Nafion (registered trademark) or the like interposed therebetween, and a fuel gas such as hydrogen is brought into contact with the surface of one of the electrodes. An oxygen-containing gas containing oxygen is brought into contact with the surface of one of the electrodes, and electric energy is taken out between the electrodes by using an electrochemical reaction that occurs at this time (see Non-Patent Documents 1 and 2).

  Here, in the fuel cell, water is generated together with power generation. However, if the amount of generated water is excessive, moisture inhibits oxygen diffusion (flooding phenomenon), and the performance of the fuel cell deteriorates. On the other hand, when the moisture in the fuel cell is insufficient, the ionic conductivity of the solid polymer electrolyte membrane is lowered, and the performance of the fuel cell is lowered. For this reason, in order to achieve stable and high-performance battery performance of the polymer electrolyte fuel cell, water management in the fuel cell is important.

The Chemical Society of Japan, “Chemical Review No. 49, Material Chemistry of New Batteries”, Academic Publishing Center, 2001, p. 180-182 “Polymer fuel cell <2001 edition>”, Technical Information Association, 2001, p. 14-15

  By the way, currently, the electrode of the polymer electrolyte fuel cell is generally made of a paste or slurry containing catalyst powder prepared by supporting a noble metal catalyst such as platinum on granular carbon such as carbon black, carbon paper or the like. It is formed by coating on a conductive porous support. However, carbon paper and granular carbon used for the electrodes of the polymer electrolyte fuel cell are essentially hydrophobic materials and do not have a moisture retention function, and therefore cannot suppress the flooding phenomenon. . Therefore, development of a conductive material that can be suitably used for an electrode of a polymer electrolyte fuel cell and has a high moisture retention function is currently required.

  The noble metal catalyst carrier is also required to have a large surface area in order to improve the catalytic activity of the noble metal catalyst. Therefore, development of a high surface area catalyst carrier suitable for supporting a noble metal catalyst is also demanded.

  Accordingly, an object of the present invention is to provide a method for producing a carbon material capable of solving the above-mentioned problems of the prior art and producing a carbon material having a high moisture retention function and a carbon material having a large surface area. Another object of the present invention is to provide a polymer electrolyte fuel cell electrode using the carbon material produced by such a method, and a polymer electrolyte fuel cell equipped with the electrode.

As a result of intensive studies to achieve the above object, the present inventors have produced a fibril-like polymer by oxidative polymerization of a compound having an aromatic ring, and the resulting fibril-like polymer is fired to have a three-dimensional continuous structure. In the carbon fiber manufacturing method for generating carbon fibers, the density of the fibrillated polymer and carbon fibers to be generated is increased by performing oxidative polymerization while irradiating ultrasonic waves, and the ultrasonic irradiation conditions are changed. Thus, it was found that the density of the carbon fibers to be generated can be controlled. Further, the present inventors have found that carbon fibers having a high density have a high moisture retention function, have a large surface area, a porous support such as carbon paper, and a carbon fiber disposed on the porous support. In the polymer electrolyte fuel cell electrode composed of the metal catalyst supported on the carbon fiber, by disposing the high-density carbon fiber on the polymer electrolyte membrane side, the moisture retention function of the electrode is improved, Since the amount of the noble metal catalyst supported on the electrode can be increased and the low-density carbon fibers are arranged on the porous support side, the diffusibility of gas (H ₂ , O ₂ ) can be maintained high. It has been found that a high performance polymer electrolyte fuel cell electrode can be obtained, and the present invention has been completed.

That is, the method for producing the carbon fiber of the present invention includes:
A step of oxidatively polymerizing a compound having an aromatic ring while irradiating ultrasonic waves to form a fibrillated polymer;
And firing the fibrillated polymer to produce a carbon fiber having a three-dimensional continuous structure.

  In a preferred embodiment of the carbon fiber production method of the present invention, the oxidative polymerization is electrolytic oxidative polymerization.

  In another preferred embodiment of the carbon fiber production method of the present invention, the compound having an aromatic ring is a compound having a benzene ring or an aromatic heterocycle. Here, the compound having an aromatic ring is more preferably at least one compound selected from the group consisting of aniline, pyrrole, thiophene and derivatives thereof.

  In another preferred embodiment of the carbon fiber production method of the present invention, the firing is performed in a non-oxidizing atmosphere and a weakly oxidizing atmosphere.

  In addition, the carbon fiber of the present invention is manufactured by the above method.

  Furthermore, an electrode for a polymer electrolyte fuel cell of the present invention comprises a porous support, the carbon fiber disposed on the porous support, and a metal catalyst supported on the carbon fiber. It is characterized by that.

  In the polymer electrolyte fuel cell electrode of the present invention, the carbon fiber disposed on the porous support has a density at a portion farther from the porous support than at a portion closer to the porous support. High is preferred.

  In a preferred example of the polymer electrolyte fuel cell electrode of the present invention, the porous support is carbon paper.

  In a preferred example of the polymer electrolyte fuel cell electrode of the present invention, the metal catalyst contains at least Pt.

  Furthermore, the polymer electrolyte fuel cell of the present invention is characterized by comprising the above-mentioned electrode for a polymer electrolyte fuel cell.

  According to the present invention, a carbon fiber in which a compound having an aromatic ring is oxidatively polymerized while being irradiated with ultrasonic waves to produce a fibril-like polymer, and the fibril-like polymer is baked to produce a carbon fiber having a three-dimensional continuous structure. In the production method of, the density of the fibrillated polymer to be produced and the finally obtained carbon fiber can be easily changed by changing the irradiation condition of the ultrasonic wave to be irradiated.

<Carbon fiber and its manufacturing method>
Hereinafter, the carbon fiber of the present invention and the production method thereof will be described in detail. The method for producing carbon fiber of the present invention comprises a step of oxidatively polymerizing a compound having an aromatic ring while irradiating ultrasonic waves to produce a fibril-like polymer, and a carbon having a three-dimensional continuous structure by firing the fibril-like polymer. The carbon fiber of the present invention is manufactured by such a method. In the carbon fiber production method of the present invention, the density of the fibrillated polymer to be produced can be easily controlled by changing the ultrasonic irradiation conditions in the fibrillar polymer producing step.

  The carbon fiber of the present invention can be obtained by oxidative polymerization of a compound having an aromatic ring while irradiating ultrasonic waves to produce a fibril-like polymer, and then firing the fibril-like polymer. Examples of the compound having an aromatic ring include a compound having a benzene ring and a compound having an aromatic heterocyclic ring. Here, aniline and aniline derivatives are preferred as the compound having a benzene ring, and pyrrole, thiophene and derivatives thereof are preferred as the compound having an aromatic heterocycle. These compounds having an aromatic ring may be used alone or in a mixture of two or more.

  The ultrasonic wave used in the manufacturing method of the present invention is a sound wave or elastic vibration having a frequency higher than the human audible limit, that is, a frequency higher than 20 kHz. The ultrasonic waves can be generated using a general ultrasonic generator. Here, in the present invention, the density of the fibrillated polymer to be generated can be controlled by changing the frequency of ultrasonic waves, the irradiation time of ultrasonic waves, and the like. In the method of the present invention, ultrasonic waves may be applied consistently throughout the oxidative polymerization of the compound having an aromatic ring, or ultrasonic waves may be applied only for a certain period during the oxidative polymerization of the compound having an aromatic ring. For example, by increasing the ultrasonic irradiation time during oxidative polymerization, the density of the fibrillated polymer produced can be increased, and the ultrasonic irradiation time during oxidative polymerization can be shortened. Thus, the density of the fibrillated polymer produced can be lowered. Although not particularly limited, the frequency of the ultrasonic wave to be used is preferably in the range of 20 to 30 kHz, and the ultrasonic irradiation time is preferably from the start of polymerization to just before the end of polymerization. Continuing irradiation after polymerization may lead to polymer peeling.

  The fibrillar polymer obtained by oxidative polymerization of the compound having an aromatic ring usually has a three-dimensional continuous structure, a diameter of 30 to several hundred nm, preferably 40 to 500 nm, and a length of 0.5 to The thickness is 100000 μm, preferably 1 to 10,000 μm. The density of the fibrillar polymer can be controlled by changing the ultrasonic irradiation conditions as described above.

  As the oxidative polymerization method, an electrolytic oxidative polymerization method is preferable. Moreover, in oxidative polymerization, it is preferable to mix an acid with the compound which has a raw material aromatic ring. In this case, the negative ion of the acid is taken into the fibril polymer synthesized as a dopant to obtain a fibril polymer excellent in conductivity, and the conductivity of the carbon fiber finally obtained by using this fibril polymer is obtained. The property can be further improved.

More specifically, for example, when aniline is used as a polymerization raw material, polyaniline obtained by oxidative polymerization of aniline in a state where HBF ₄ is mixed is usually represented by the following formulas (A) to (D):
In the state where the four polyanilines shown in FIG. 4 are mixed, that is, benzonoid = amine state (formula A), benzonoid = ammonium state (formula B), dope = semiquinone radical state (formula C) and quinoid = diimine state (formula D) ). Here, the mixing ratio of each of the above states is not particularly limited, but the quinoid = diimine state (formula D) is mostly contained when the dope = semiquinone radical state (formula C) is contained in a large amount. However, the conductivity of the finally obtained carbon fiber is increased. Therefore, in order to obtain polyaniline containing a large amount of dope = semiquinone radical state (formula C), it is preferable to mix an acid during polymerization. As the acid to be mixed in the polymerization, is not limited to the above HBF _4, can be used various ones, other _{HBF 4, H 2 SO 4,} HCl, illustrate HClO _4, etc. can do. Here, the concentration of the acid is preferably 0.1 to 3 mol / L, and more preferably 0.5 to 2.5 mol / L.

  The content ratio (doping level) of the dope = semiquinone radical state (formula C) can be adjusted as appropriate, and the conductivity of the resulting carbon fiber can be controlled by adjusting the content ratio (doping level). The conductivity of the carbon fiber obtained by increasing the doping level increases. Although not particularly limited, the content ratio (doping level) of the dope = semiquinone radical state (formula C) is usually preferably in the range of 0.01 to 50%.

When obtaining a fibrillated polymer by electrolytic oxidation polymerization, the working electrode and the counter electrode are immersed in a solution containing a compound having an aromatic ring, and a voltage higher than the oxidation potential of the compound having the aromatic ring is applied between both electrodes. Alternatively, it is sufficient to pass a current under such a condition that a voltage sufficient to polymerize the compound having the aromatic ring can be secured, whereby a fibril polymer is formed on the working electrode. Here, as the working electrode and the counter electrode, a plate made of a highly conductive material such as stainless steel, platinum, or carbon, a porous support, or the like can be used. An example of a method for synthesizing a fibril-like polymer by this electrolytic oxidation polymerization method is as follows. The working electrode and the counter electrode are immersed in an electrolytic solution containing an acid such as H ₂ SO ₄ and HBF ₄ and a compound having an aromatic ring. For example, a method of polymerizing and depositing a fibrillated polymer on the working electrode side by applying a current of 0.1 to 1000 mA / cm ² , preferably 0.2 to 100 mA / cm ² , is exemplified. Here, the concentration of the compound having an aromatic ring in the electrolytic solution is preferably 0.05 to 3 mol / L, and more preferably 0.25 to 1.5 mol / L. Moreover, in addition to the said component, you may add a soluble salt etc. to an electrolyte solution suitably in order to adjust pH.

  As described above, the conductivity of the obtained carbon fiber can be controlled by adjusting the doping level of the carbon fiber. However, the doping level can be adjusted by reducing the fibrillated polymer obtained by some method. Well, there are no particular restrictions on the method. Specific examples include a method of immersing in an aqueous ammonia solution or an aqueous hydrazine solution, a method of electrochemically applying a reduction current, and the like. The amount of dopant contained in the fibril-like polymer can be controlled by this reduction level. In this case, the amount of dopant in the fibril-like polymer is reduced by the reduction treatment. Although the doping level can be adjusted to some extent during the polymerization process by controlling the acid concentration during the polymerization, it is difficult to obtain various samples with greatly different doping levels. Therefore, the above reduction method is preferably employed. The In addition, the dopant which adjusted the content rate in this way is hold | maintained in the carbon fiber obtained by controlling the baking conditions after the baking process mentioned later, and, thereby, the electrical conductivity of carbon fiber is controlled.

  The fibrillated polymer obtained on the working electrode as described above is washed with a solvent such as water or an organic solvent, dried and then calcined by firing, preferably calcined by firing in a non-oxidizing atmosphere. By doing so, a carbon fiber is obtained. Here, the drying method is not particularly limited, and examples thereof include a method using a fluidized bed drying device, an air dryer, a spray dryer, etc., in addition to air drying and vacuum drying. In addition, the firing conditions are not particularly limited, and may be set as appropriate so as to obtain the optimum conductivity. Particularly, when high conductivity is required, the temperature is 500 to 3000 ° C., preferably 600 to Baking is preferably performed at 2800 ° C. for 0.5 to 6 hours. Note that examples of the non-oxidizing atmosphere include a nitrogen atmosphere, an argon atmosphere, and a helium atmosphere, and in some cases, a hydrogen atmosphere can also be used. Furthermore, the diameter of the carbon fibers can be intentionally reduced by firing in a weakly oxidizing atmosphere.

The carbon fiber has a three-dimensional continuous structure, a diameter of 30 to several hundred nm, preferably 40 to 500 nm, a length of 0.5 to 100,000 μm, preferably 1 to 10,000 μm, and a surface resistance of 10 ⁶ to 10 ⁻² Ω, preferably 10 ⁴ to 10 ⁻² Ω. The carbon fiber has a residual carbon ratio of 95 to 30%, preferably 90 to 40%. The carbon fiber has a structure in which the entire carbon is three-dimensionally continuous, and therefore has higher conductivity than the granular carbon and also has a high moisture retention function.

<Electrode for polymer electrolyte fuel cell>
The electrode for a polymer electrolyte fuel cell of the present invention comprises a porous support, the above-described carbon fiber disposed on the porous support, and a metal catalyst supported on the carbon fiber. Since the carbon fiber has a high water holding function, the polymer electrolyte fuel cell electrode of the present invention has a high water holding function. Therefore, the flooding phenomenon of the polymer electrolyte fuel cell can be prevented by using the electrode of the present invention.

  The electrode for a polymer electrolyte fuel cell of the present invention can be produced, for example, by producing the carbon fiber on a porous support and then supporting a metal catalyst on the carbon fiber. Can also be used as an air electrode (oxygen electrode). Here, in the polymer electrolyte fuel cell electrode, the porous support functions as a gas diffusion layer, and the carbon fiber functions as a carrier for the gas diffusion layer and the catalyst layer.

  As described above, the carbon fiber of the present invention can control the density by changing the ultrasonic irradiation conditions, but in the carbon fiber disposed on the porous support, the porous support By increasing the density of the part far from the porous support, the moisture retention function of the part far from the porous support can be increased and the amount of catalyst supported can be increased, increasing the gas diffusibility of the part close to the porous support. Therefore, stabilization of the battery performance and high performance of the solid polymer fuel cell can be achieved at the same time.

  The porous support used for the electrode for the polymer electrolyte fuel cell of the present invention supplies a fuel such as hydrogen gas or an oxygen-containing gas such as oxygen or air to the carbon fiber (catalyst layer) on which the metal is supported. It functions as a gas diffusion layer and as a current collector that exchanges generated electrons. The material used for the porous support may be any material that is porous and has electronic conductivity, and specific examples include carbon paper and porous carbon cloth, and carbon paper is preferred.

  As the metal supported on the carbon fiber, a noble metal is preferable, and Pt is particularly preferable. In the present invention, Pt may be used alone or as an alloy with another metal such as Ru. By using Pt as the noble metal, hydrogen can be oxidized with high efficiency even at a low temperature of 100 ° C. or lower. Further, by using an alloy such as Pt and Ru, it is possible to prevent poisoning of Pt by CO and prevent a decrease in the activity of the catalyst. The particle size of the metal supported on the carbon fiber is preferably in the range of 0.5 to 20 nm, and the support rate of the metal is preferably in the range of 0.05 to 5 g with respect to 1 g of the carbon fiber.

The carbon fiber metal-supported portion may be further impregnated with a polymer electrolyte. As the polymer electrolyte, an ion conductive polymer can be used, and as the ion conductive polymer, Can include polymers having ion exchange groups such as sulfonic acid, carboxylic acid, phosphonic acid, phosphonous acid, etc., and the polymer may or may not contain fluorine. Examples of the ion conductive polymer include perfluorocarbon sulfonic acid polymers such as Nafion (registered trademark). The amount of impregnation of the polymer electrolyte is preferably in the range of 10 to 500 parts by mass of the polymer electrolyte with respect to 100 parts by mass of the carbon fiber. The thickness of the carbon fiber layer is not particularly limited, but is preferably in the range of 0.1 to 100 μm. The amount of metal supported on the carbon fiber layer is determined by the supporting rate and the thickness of the carbon fiber layer, and is preferably in the range of 0.001 to 0.8 mg / cm ² .

<Solid polymer fuel cell>
Next, a polymer electrolyte fuel cell using the polymer electrolyte fuel cell electrode of the present invention will be described with reference to FIG. The illustrated polymer electrolyte fuel cell includes a membrane electrode assembly (MEA) 1 and separators 2 located on both sides thereof. The membrane electrode assembly (MEA) 1 includes a solid polymer electrolyte membrane 3 and fuel electrodes 4A and air electrodes 4B located on both sides thereof. In the fuel electrode 4A, a reaction represented by 2H ₂ → 4H ⁺ + 4e ⁻ occurs, the generated H ⁺ passes through the solid polymer electrolyte membrane 3 to the air electrode 4B, and the generated e ⁻ is taken out to the outside. Current. On the other hand, in the air electrode 4B, a reaction represented by O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O occurs, and water is generated. Here, in the polymer electrolyte fuel cell of the present invention, since the above-described electrode having a high water retention function is used, occurrence of a flooding phenomenon is prevented.

  The fuel electrode 4 </ b> A and the air electrode 4 </ b> B are composed of a metal-supporting carbon fiber 5 and a porous support 6, and are disposed so that the metal-supporting carbon fiber 5 is in contact with the solid polymer electrolyte membrane 3. Here, the metal-supporting carbon fiber 5 is formed by supporting a metal on the carbon fiber, and since the surface area of the supported metal is very wide, the three-phase of the solid polymer electrolyte membrane 3, the metal-supporting carbon fiber 5, and gas. The reaction field of the electrochemical reaction at the interface is very large, and as a result, the power generation efficiency of the polymer electrolyte fuel cell is greatly improved. As the solid polymer electrolyte membrane 3, an ion conductive polymer can be used, and the ion conductive polymer can be impregnated in a portion where the metal of the carbon fiber is supported. What was illustrated as a molecular electrolyte can be used. Moreover, as the separator 2, the normal separator with which flow paths (not shown), such as fuel, air, and produced | generated water, were formed in the surface can be used.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples.

Example 1
In a reaction vessel containing aniline monomer 0.5 mol / L and HBF ₄ 1.0 mol / L, a working electrode made of carbon paper [manufactured by Toray] was installed, a platinum plate was installed as a counter electrode, and the reaction vessel was It was installed in an ultrasonic bath of a sound wave generator [manufactured by NN Corporation]. Next, electrolytic polymerization was performed at a constant current of 35 mA / cm ² at room temperature while irradiating ultrasonic waves under the conditions of frequency: 38 kHz and high-frequency motion (output): 80 W (amount of electricity 3 C), and polyaniline was applied to the working electrode. Electrodeposited. The obtained polyaniline was washed with ion-exchanged water and then vacuum-dried for 24 hours. Further, the obtained polyaniline was heated together with carbon paper to 950 ° C. at a rate of temperature increase of 3 ° C./min in an Ar atmosphere, and then held at 950 ° C. for 1 hour for firing treatment. When the obtained fired product was observed with an SEM, it was confirmed that the density was higher than the case where the density was not irradiated. An SEM photograph of the obtained carbon fiber is shown in FIG.

(Comparative Example 1)
In a reaction vessel containing 0.5 mol / L of aniline monomer and 1.0 mol / L of HBF _4, a working electrode made of carbon paper [manufactured by Toray] is installed, a platinum plate is installed as a counter electrode, and 35 mA / cm ² at room temperature. The electropolymerization was performed at a constant current of 3 (conduction amount 3C), and polyaniline was electrodeposited on the working electrode. The obtained polyaniline was washed with ion-exchanged water and then vacuum-dried for 24 hours. Further, the obtained polyaniline was heated together with carbon paper to 950 ° C. at a rate of temperature increase of 3 ° C./min in an Ar atmosphere, and then held at 950 ° C. for 1 hour for firing treatment. When the obtained fired product was observed by SEM, it was confirmed that three-dimensional continuous carbon fibers were formed on the carbon paper. An SEM photograph of the obtained carbon fiber is shown in FIG.

  As apparent from the comparison between FIG. 2 and FIG. 3, the density of the carbon fiber finally obtained by producing fibrillar polyaniline (carbon fiber precursor) by oxidative polymerization of aniline while irradiating ultrasonic waves. Can be high.

It is sectional drawing of an example of the polymer electrolyte fuel cell using the electrode for polymer electrolyte fuel cells of this invention. 2 is a SEM photograph of the carbon fiber obtained in Example 1. 2 is a SEM photograph of the carbon fiber obtained in Comparative Example 1.

Explanation of symbols

1 Membrane electrode assembly (MEA)
2 Separator 3 Solid polymer electrolyte membrane 4A Fuel electrode 4B Air electrode 5 Metal-supported carbon fiber 6 Porous support

Claims (11)

  A carbon fiber comprising: a step of oxidatively polymerizing a compound having an aromatic ring to produce a fibril polymer by irradiating ultrasonic waves; and a step of firing the fibril polymer to produce a carbon fiber having a three-dimensional continuous structure. Manufacturing method.   The method for producing carbon fiber according to claim 1, wherein the oxidative polymerization is electrolytic oxidative polymerization.   The method for producing carbon fiber according to claim 1, wherein the compound having an aromatic ring is a compound having a benzene ring or an aromatic heterocyclic ring.   The method for producing carbon fiber according to claim 3, wherein the compound having an aromatic ring is at least one compound selected from the group consisting of aniline, pyrrole, thiophene, and derivatives thereof.   The method for producing a carbon fiber according to claim 1, wherein the firing is performed in a non-oxidizing atmosphere and a weakly oxidizing atmosphere.   Carbon fiber manufactured by the method according to any one of claims 1 to 5.   An electrode for a polymer electrolyte fuel cell comprising a porous support, the carbon fiber according to claim 6 disposed on the porous support, and a metal catalyst supported on the carbon fiber.   8. The solid according to claim 7, wherein the carbon fiber disposed on the porous support has a higher density in a portion far from the porous support than in a portion close to the porous support. Polymer type fuel cell electrode.   8. The polymer electrolyte fuel cell electrode according to claim 7, wherein the porous support is carbon paper.   8. The polymer electrolyte fuel cell electrode according to claim 7, wherein the metal catalyst contains at least Pt. The polymer electrolyte fuel cell provided with the electrode for polymer electrolyte fuel cells in any one of Claims 7-10.