JPWO2005041330A1 - Membrane / electrode assembly for polymer electrolyte fuel cell and method for producing the same - Google Patents

Abstract

Providing membrane / electrode assemblies for polymer electrolyte fuel cells that have high initial power generation performance and can maintain stable output characteristics over a long period of time. An anode and a cathode having a catalyst layer containing a catalyst powder in which catalytic metal particles are supported on a carbon support and an ion exchange resin; an ion exchange membrane disposed between the catalyst layer of the anode and the catalyst layer of the cathode; And at least one of the catalyst layer of the anode and the catalyst layer of the cathode contains an amine having a solubility in water of 3 or less at 20 ° C. Of the catalyst powder (W × N) / M × 1000 is set to 0.03 to 1 (where W is the content (g) of the amine per 1 g of the catalyst powder, M is the molecular weight of the amine, N Is the number of basic nitrogen atoms in one amine molecule.) As the amine, HALS is particularly preferable.

Description

  The present invention relates to a membrane / electrode assembly for a polymer electrolyte fuel cell, which has a high initial output voltage and can provide a high output voltage over a long period of time, and a method for producing the same.

  A fuel cell is a cell that directly converts the reaction energy of a gas that is a raw material into electric energy. In a hydrogen / oxygen fuel cell, the reaction product is only water in principle and has little influence on the global environment. In particular, a polymer electrolyte fuel cell using a solid polymer membrane as an electrolyte has been developed as a polymer electrolyte membrane having high ionic conductivity, and can operate at room temperature to obtain a high output density. For this reason, with increasing social demands for energy and global environmental problems in recent years, there is great expectation as a power source for mobile vehicles for electric vehicles and small cogeneration systems.

  In a polymer electrolyte fuel cell, an ion exchange membrane having a cation exchange group is usually used as an electrolyte membrane, and an ion exchange membrane made of a perfluorocarbon polymer having a sulfonic acid group is particularly excellent in basic characteristics. In a polymer electrolyte fuel cell, gas diffusible electrode layers are arranged on both surfaces of an ion exchange membrane, and a gas containing hydrogen as a fuel and a gas containing oxygen (such as air) as an oxidant are respectively supplied to an anode and a cathode. To generate electricity.

Since the oxygen reduction reaction at the cathode of the polymer electrolyte fuel cell proceeds via hydrogen peroxide (H ₂ O ₂ ), hydrogen peroxide or peroxide radicals generated in the catalyst layer There is concern about the possibility of causing deterioration of the electrolyte membrane. Moreover, since oxygen molecules permeate through the membrane from the cathode to the anode, it is conceivable that hydrogen molecules and oxygen molecules cause a reaction at the anode to generate radicals. In particular, when a hydrocarbon resin membrane is used as an electrolyte membrane, the stability against radicals is poor, which has been a major problem in long-term operation. For example, the polymer electrolyte fuel cell was first put into practical use when it was used as a power source for a Gemini spacecraft in the United States. At this time, a membrane obtained by sulfonating a styrene-divinylbenzene polymer was used as an electrolyte membrane. However, there was a problem with durability over a long period of time. For this reason, a perfluorocarbon polymer having a sulfonic acid group has attracted attention as a polymer having excellent radical stability, and it is known that an ion exchange membrane made of the polymer can be used as an electrolyte membrane.

  Further, in order to further enhance the stability against radicals, a system in which a transition metal oxide capable of catalytically decomposing peroxide radicals or a compound having a phenolic hydroxyl group is added to the electrolyte membrane (Patent Document 1), or a catalyst in the electrolyte membrane. A technology for supporting metal particles and decomposing hydrogen peroxide (Patent Document 2) is also disclosed. However, these techniques are techniques for adding materials only into the electrolyte membrane, and do not attempt to improve the catalyst layer, which is a source of hydrogen peroxide or peroxide radicals. Therefore, although there is an improvement effect at the beginning, there is a possibility that a big problem occurs in durability over a long period of time. There is also a problem that the cost becomes high.

Further, a solid polymer fuel cell comprising a supported catalyst formed by treating the carbon surface of a catalyst with N, N-dimethylaminopropylamine is known (Patent Document 3). Since propylamine was filtered after being used for the treatment of the catalyst, the amine was not sufficiently left in the catalyst, and the effect of improving the durability was insufficient. Furthermore, since N, N-dimethylaminopropylamine used here has high solubility in water and is hydrophilic, it is eluted by water generated during operation of the fuel cell, and its effect tends to be reduced. There was a point.
JP 2001-118591 A (Claims) Japanese Patent Laid-Open No. 06-103992 (page 2, lines 33 to 37) JP 2002-373663 A (Example 1)

  In recent years, polymer electrolyte fuel cells are expected to be used as power sources for automobiles and residential markets, and the demand for practical use is increasing and development is accelerating. In these applications, operation with particularly high efficiency is required. Therefore, operation at a higher voltage is desired, and at the same time, it is desirable to obtain a stable output over a long period of time. Moreover, in order to ensure the electroconductivity of the electrolyte membrane, it is necessary to humidify the electrolyte membrane. However, operation with low or no humidification is often required from the viewpoint of the efficiency of the entire fuel cell system.

  Therefore, the present invention is capable of generating power with sufficiently high energy efficiency in practical use of a polymer electrolyte fuel cell for in-vehicle use, residential use market, etc., and at the same time has excellent durability over a long period of time. It is an object of the present invention to provide a membrane / electrode assembly for a polymer electrolyte fuel cell and a method for producing the same. In order to obtain high durability, an object of the present invention is to provide a membrane / electrode assembly having a catalyst layer in which hydrogen peroxide and peroxide radicals are unlikely to be generated with power generation, and a method for producing the same.

  The present invention is arranged between an anode and a cathode having a catalyst layer containing a catalyst powder in which catalyst metal particles are supported on a carbon support and an ion exchange resin, and the catalyst layer of the anode and the catalyst layer of the cathode. A membrane / electrode assembly for a polymer electrolyte fuel cell having an ion exchange membrane, wherein at least one of the catalyst layer of the anode and the catalyst layer of the cathode is an amine having a water solubility of 3 or less at 20 ° C. (Hereinafter also referred to as the present amine), and the content (W × N) / M × 1000 of the present amine with respect to the catalyst powder is 0.03 to 1 (where W is the amount per 1 g of the catalyst powder of the present amine). Content (g), M is the molecular weight of the amine, and N is the number of basic nitrogen atoms in one molecule of the amine.) Membrane / electrode assembly for polymer electrolyte fuel cell I will provide a.

  The present invention also provides an anode and a cathode having a catalyst layer containing a catalyst powder in which catalyst metal particles are supported on a carbon support and an ion exchange resin, and the anode catalyst layer and the cathode catalyst layer. A membrane-electrode assembly for a polymer electrolyte fuel cell, wherein the amine is contained in at least one of the catalyst layer of the anode and the catalyst layer of the cathode. Provided is a membrane / electrode assembly for a polymer electrolyte fuel cell, characterized in that the content with respect to the catalyst powder is 0.3 to 30% by mass.

  The present invention also provides an anode and a cathode having a catalyst layer containing a catalyst powder in which catalyst metal particles are supported on a carbon support and an ion exchange resin, and the anode catalyst layer and the cathode catalyst layer. A membrane / electrode assembly for a polymer electrolyte fuel cell comprising an ion exchange membrane, comprising the catalyst powder, the ion exchange resin, and the amine, and the catalyst powder of the amine A coating liquid having a content (W × N) / M × 1000 of 0.03 to 1 was prepared, and a catalyst layer was formed by coating the coating liquid on a substrate. Provided is a method for producing a membrane / electrode assembly for a polymer electrolyte fuel cell, wherein the catalyst layer is at least one of an anode catalyst layer and a cathode catalyst layer.

  The present invention also provides an anode and a cathode having a catalyst layer containing a catalyst powder in which catalyst metal particles are supported on a carbon support and an ion exchange resin, and the anode catalyst layer and the cathode catalyst layer. A membrane / electrode assembly for a polymer electrolyte fuel cell comprising an ion exchange membrane, comprising the catalyst powder, the ion exchange resin, and the amine, and the catalyst powder of the amine A coating liquid having a mass ratio of 0.3 to 30% by weight is prepared, and a catalyst layer is formed by coating the coating liquid on a substrate. Provided is a method for producing a membrane / electrode assembly for a polymer electrolyte fuel cell, characterized in that it is at least one of a catalyst layer of a cathode.

  A polymer electrolyte fuel cell incorporating a membrane / electrode assembly containing a catalyst powder, which is said to have a high catalytic activity, tends to generate hydrogen peroxide and peroxide radicals during power generation. The output tends to decrease. The fuel cell incorporating the membrane-electrode assembly of the present invention has less performance deterioration even if it generates power for a long time. The reason for this is that in the present invention, the amine is contained in the catalyst layer, so that the amine has a function of decomposing peroxides and capturing radicals. This is probably because oxide radicals are less likely to be generated.

Sectional drawing which shows the embodiment of the membrane-electrode assembly for polymer electrolyte fuel cells of this invention.

Explanation of symbols

1: solid polymer electrolyte membrane,
2: Anode catalyst layer,
3: Cathode catalyst layer,
4, 4 ': Gas diffusion layer,
5: Separator,
5a: separator gas supply groove,
6: Gas seal body,
7: Membrane / electrode assembly.

A cross-sectional view of one embodiment of the membrane / electrode assembly for a polymer electrolyte fuel cell of the present invention is shown in FIG. Hereinafter, the membrane-electrode assembly 7 will be described with reference to FIG. The membrane / electrode assembly 7 includes a solid polymer electrolyte membrane 1, an anode catalyst layer 2 and a cathode catalyst layer 3 in close contact with the membrane surface of the electrolyte membrane 1, and gas diffusion layers 4, 4 in close contact with these catalyst layers. And a gas seal body 6. The anode catalyst layer 2 and the cathode catalyst layer 3 are disposed between the gas diffusion layers 4, 4 ′ and the solid polymer electrolyte membrane 1. The solid polymer electrolyte membrane 1 has a role of selectively transmitting protons generated in the anode catalyst layer 2 to the cathode catalyst layer 3 along the film thickness direction. The solid polymer electrolyte membrane 1 also has a function as a diaphragm for preventing hydrogen supplied to the anode and oxygen supplied to the cathode from being mixed. The gas diffusion layers 4 and 4 'are usually made of a porous conductive base material, and may not necessarily be provided. Are preferably provided. On the outside of the membrane / electrode assembly 7, a separator 5 in which a groove to be a gas flow path 5a is formed is disposed. For example, hydrogen gas obtained by reforming a fuel such as methanol or natural gas is supplied to the anode side through a groove of the separator. In this specification, when the membrane / electrode assembly 7 includes the gas diffusion layers 4 and 4 ′, the gas diffusion layers 4 and 4 ′ and the catalyst layers 2 and 3 are collectively referred to as an electrode.
Hereinafter, the present invention will be described in detail.

  In the present invention, the anode catalyst layer 2 includes, for example, a catalyst powder in which an alloy of platinum and ruthenium is supported on a carbon support and an ion exchange resin. The cathode catalyst layer 3 includes a catalyst powder in which platinum or a platinum alloy is supported on a carbon support and an ion exchange resin. In the present invention, the ion exchange resin is preferably a hydrocarbon resin or a fluorine-containing hydrocarbon resin having a cation exchange group, and is a perfluorocarbon polymer having a sulfonic acid group (which may contain an etheric oxygen atom). Is particularly preferred because of its excellent radical stability. Examples of the cation exchange group include a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, and a phosphoric acid group.

The perfluorocarbon polymer having a sulfonic acid _{group, CF 2 = CF- (OCF 2} CFX) m -O p - (CF 2) a perfluorovinyl compound represented by n -SO ₃ H (m is 0 to 3 N represents an integer of 1 to 12, p represents 0 or 1, X represents a fluorine atom or a trifluoromethyl group, and a polymer unit based on tetrafluoroethylene; It is preferable that it is a copolymer containing.

  Preferable examples of the fluorovinyl compound include compounds represented by the following formulas (i) to (iii). However, in the following formula, q is an integer of 1 to 8, r is an integer of 1 to 8, and t is an integer of 1 to 3.

  Various conventionally known hydrocarbon resins having a cation exchange group can be used. Examples of the hydrocarbon resin having a cation exchange group include acrylic acid / divinylbenzene copolymer, methacrylic acid / divinylbenzene copolymer, phenolsulfonic acid resin, polystyrenesulfonic acid, sulfonated polyimide, and the like. Examples thereof include those obtained by introducing a cation exchange group into a polymer such as divinylbenzene copolymer, styrene / butadiene copolymer, polyethersulfone, polyetheretherketone, polyolefin, polyvinyl chloride, and polyethylene.

  In addition, as the partially fluorinated hydrocarbon resin having a cation exchange group, in the above-described hydrocarbon resin having a cation exchange group, a hydrogen atom other than a functional group such as an ion exchange group is partially substituted with a fluorine atom. Can be used. Other ion exchange resins such as polystyrene sulfonic acid graft-poly (trifluorostyrene), polystyrene sulfonic acid graft-poly (ethylene / tetrafluoroethylene), tetrafluoroethylene / ethylene copolymer, vinylidene fluoride resin, Trifluoro-chloroethylene resin, polystyrene graft-polytetrafluoroethylene, poly (trifluorostyrene) graft-poly (ethylene tetrafluoroethylene), styrene-divinylbenzene copolymer graft-poly (perfluoroethylene propene), Examples thereof include those obtained by introducing a cation exchange group into a resin such as polystyrene graft-poly (perfluoroethylene propene).

  In the present invention, the amine is contained in at least one of the anode catalyst layer 2 and the cathode catalyst layer 3. In the reaction of the fuel cell, hydrogen peroxide is generated mainly on the anode side. Therefore, it is more effective that the amine is contained in the anode catalyst layer 2 than in the cathode catalyst layer 3. However, in order to obtain an even higher effect, it is preferable to contain both in the anode catalyst layer 2 and the cathode catalyst layer 3. By containing this amine, hydrogen peroxide and peroxide radicals are less likely to be generated. As a result, it is considered that the performance deterioration is reduced even when the fuel cell is operated for a long period of time. Although the mechanism by which hydrogen peroxide and peroxide radicals are less likely to be generated has not been elucidated in detail, it probably has an acidic functional group (—COOH) on the catalyst powder surface and basicity in the amine. It is considered that the generation of hydrogen peroxide and peroxide radicals is suppressed because the acidic functional group disappears when the nitrogen atom reacts. Therefore, it is considered that the suppression effect is determined by the number of basic nitrogen atoms in the amine.

The amine is preferably any of primary amines, secondary amines, and tertiary amines, and HALS is particularly preferable because it is chemically and thermally stable. In the present invention, when a fuel cell having a catalyst layer containing the present amine is operated, even if water is generated by the reaction of the cell, the present amine is preferable because it is difficult to separate from the catalyst layer during operation.
Here, HALS is a general term for hindered amine light stabilizers, and has a structure in which all hydrogen atoms on the 2nd and 6th carbons of piperidine are substituted with methyl groups. is there.

  The HALS used as the amine usually has a structure in which the 2-position and 6-position of piperidine are all substituted with methyl groups, preferably a group represented by Formula 1. However, X in Formula 1 represents a hydrogen atom or an alkyl group. Among the groups represented by Formula 1, 2,2,6,6-tetramethyl-4-piperidyl group in which X is a hydrogen atom, or 1,2,2,6,6-pentamethyl in which X is a methyl group HALS having a -4-piperidyl group is particularly preferably employed. A number of HALS having a structure in which a group represented by Formula 1 is bonded to a —COO— group, that is, a group represented by Formula 2, are commercially available, but these can be preferably used.

Specific examples of HALS that can be preferably used in the present invention include those represented by the following formulas. Here, 2,2,6,6-tetramethyl-4-piperidyl group is represented by R, and 1,2,2,6,6-pentamethyl-4-piperidyl group is represented by R ′.
_{ROC (= O) (CH 2} ) 8 C (= O) OR, ROC (= O) C (CH 3) = CH 2, R'OC (= O) C (CH 3) = CH 2, CH 2 ( COOR) CH (COOR) CH (COOR) CH ₂ COOR, CH ₂ (COOR ′) CH (COOR ′) CH (COOR ′) CH ₂ COOR ′, compounds represented by Formula 3, and the like.

  Specific products include Tinuvin 123, Tinuvin 144, Tinuvin 765, Tinuvin 770, Tinuvin 622, Chimassorb 944, Chimassorb 119 (all of which are trade names of Ciba Specialty Chemicals), ADK STAB LA52, ADK STAB LA57 , Adeka Stub LA62, Adeka Stub LA67, Adeka Stub LA82, Adeka Stub LA87, Adeka Stub LX335 (all of which are trade names of Asahi Denka Kogyo Co., Ltd.) and the like, but are not limited thereto.

Among HALS, those having relatively small molecules are preferable because they can penetrate deep into the pores of the catalyst. Preferred HALS from this viewpoint includes a compound represented by ROC (═O) (CH ₂ ) ₈ C (═O) OR, R′OC (═O) C (CH ₃ ) ═CH ₂ .

  In addition to HALS, the present amine is specifically 2-ethylhexylamine, 3- (2-ethylhexyloxy) propylamine, diisobutylamine, di-n-octylamine, tri-n-octylamine, One or more selected from the group consisting of triallylamine, di-2-ethylhexylamine and 3- (dibutylamino) propylamine can also be preferably used. Similar to HALS, those having a relatively small molecule, for example, 2-ethylhexylamine, diisobutylamine, etc., are preferable because they can penetrate deep into the pores of the catalyst.

  The amine needs to have a water solubility of 3 or less. When the amine solubility in water exceeds 3, the ratio of elution from the catalyst surface to the surrounding water during the operation of the fuel cell increases, and the effect of improving the durability gradually diminishes. The solubility of the amine in water is particularly preferably 1 or less. In the present invention, the solubility of the amine in water means the mass of the amine dissolved in 100 g of water at 20 ° C.

In the present invention, the content (W × N) / M × 1000 of the present amine in the catalyst layer is preferably 0.03 to 1, and particularly preferably 0.05 to 0.7. However, W is the content (g) per gram of catalyst powder of the present amine, M is the molecular weight of the present amine, and N is the number of basic nitrogen atoms in one molecule of the present amine. In addition, the nitrogen atom which has basicity shows the number of the nitrogen atoms which act as an amine. In the present amine, the basic nitrogen atom is represented by a nitrogen atom having any one of the following formulas (iv) to (vi). In the following formula, R _a , R _b , R _c , R _d , R _e , and R _f represent a monovalent organic group. In addition, in the case of HALS, it has the coupling | bonding of Formula (v) or (vi) normally.

For example, in the case of HALS, the number of basic nitrogen atoms is N = 2 if ROC (═O) (CH ₂ ) ₈ C (═O) OR, and CH ₂ (COOR) CH ( For COOR) CH (COOR) CH ₂ COOR, N = 4. In the case of the present amine other than HALS, for example, N = 1 for tri-n-octylamine and N = 2 for 3- (dibutylamino) propylamine.

  Moreover, when the preferable range of content of this amine is shown by mass ratio with a catalyst powder, 0.3-30% is preferable by mass ratio with respect to catalyst powder, and 1-20% is especially preferable. If the amine content is too small, sufficient durability cannot be obtained when the fuel cell is operated. In addition, if the amine content is too high, the coating properties are deteriorated, for example, when the catalyst layer forming coating solution contains the amine and the catalyst layer is likely to crack. Further, the performance as a fuel cell also decreases.

  In the supported catalyst of the present invention, the catalyst metal and the carbon support are preferably in a mass ratio (catalyst metal: carbon support) of 2: 8 to 7: 3, particularly preferably 4: 6 to 6: 4. . Within this range, the thickness of the catalyst layer can be reduced, gas diffusibility can be increased, and excellent output characteristics can be obtained. If the content of the catalyst metal in the catalyst powder is too small, the amount of the catalyst metal required for the reaction may be insufficient. If the content of the catalyst metal is too large, the catalyst metal particles aggregate on the carbon support. There is a risk that the performance will be reduced.

  In the present invention, various carbon materials such as carbon black, activated carbon, carbon nanotubes, and carbon nanohorns having fine pores can be preferably used as the carbon material used as the support for the supported catalyst. In the polymer electrolyte fuel cell, carbon black is usually used, and examples of the carbon black include channel black, furnace black, thermal black, and acetylene black. Moreover, as activated carbon, various activated carbons obtained by carbonizing and activating materials containing various carbon atoms can be used.

  In the present invention, an ion exchange membrane is used as the solid polymer electrolyte membrane 1. As the ion exchange membrane, the same type of ion exchange resin as that preferable as the resin contained in the catalyst layer can be used. That is, a hydrocarbon resin or a fluorine-containing hydrocarbon resin having a cation exchange group can be preferably used. Those made of a perfluorocarbon polymer having a sulfonic acid group are particularly preferred because of their excellent radical stability.

  The gas diffusion layers 4 and 4 ′ are usually made of a conductive porous sheet such as carbon paper, carbon cloth, or carbon felt. The gas diffusion layers 4 and 4 ′ are interposed between the catalyst layers 2 and 3 and the separator 5. As the gas diffusion layers 4 and 4 ′, carbon paper, carbon cloth, a material obtained by performing a water repellent treatment with a fluororesin on a carbon felt, or the like can be preferably used.

  In the present invention, at least one of the anode catalyst layer 2 and the cathode catalyst layer 3 is prepared by mixing a catalyst powder, an ion exchange resin, and a liquid in which the present amine is dissolved or dispersed in a solvent to prepare a catalyst layer forming coating solution. It is preferably formed by preparing, coating the coating liquid on the gas diffusion layers 4, 4 ′ or the solid polymer electrolyte membrane 1 and drying it. In addition, the coating solution is applied onto a separately prepared substrate and dried to form a catalyst layer, and then laminated with the solid polymer electrolyte membrane 1 and hot-pressed to transfer to the solid polymer electrolyte membrane 1. May be. The content of the amine is preferably 0.03 to 1 and particularly preferably 0.05 to 0.7 when expressed as content (W × N) / M × 1000 with respect to the catalyst powder. Further, the content of the amine is preferably from 0.3 to 30%, particularly preferably from 1 to 20%, when expressed as a mass ratio to the catalyst powder. Here, as a base material to which the coating liquid for forming a catalyst layer is applied, any film that is stable with respect to the dispersion medium contained in the coating liquid for forming a catalyst layer can be preferably used. For example, polypropylene, polyethylene Examples include terephthalate, ethylene / tetrafluoroethylene copolymer, polytetrafluoroethylene sheet, and the like.

  As a coating method of the above-described coating liquid for forming the catalyst layer, a method using an applicator, a bar coater, a die coater or the like, a screen printing method, a gravure printing method, or the like can be applied. Also, in the coating liquid for forming the catalyst layer, the water repellent, pore-forming agent, thickener, diluting solvent, etc. may be added as necessary to enhance the drainage of water generated by the electrode reaction. It is also possible to maintain the shape stability of the catalyst layer itself, or to improve the coating unevenness at the time of coating or to improve the coating stability. In addition to the above, as a method of incorporating the present amine into the catalyst layer, after forming the catalyst layer with the catalyst layer forming coating solution, the catalyst layer is immersed in a solution obtained by dissolving the present amine in a solvent. And a method of immersing the membrane / electrode assembly in the amine solution after preparing the membrane / electrode assembly on the outside of the catalyst layer.

  In the polymer electrolyte fuel cell having the membrane-electrode assembly of the present invention, a gas containing oxygen is supplied to the cathode, and a gas containing hydrogen is supplied to the anode. Specifically, for example, a separator in which a groove that becomes a gas flow path is formed is disposed outside both electrodes of the membrane-electrode assembly, and the gas is allowed to flow through the gas flow path to form a membrane-electrode assembly. Supply fuel gas and generate electricity. In addition to metal and carbon separators, there are separators made of a mixture of graphite and resin, and a wide variety of conductive materials can be used.

  Hereinafter, the present invention will be specifically described using Examples and Comparative Examples, but the present invention is not limited thereto. In Tables 1, 3, and 5, in each Example, the content of the amine contained in the catalyst layer is represented by a value expressed by (W × N) / M × 1000 and a mass ratio with respect to the catalyst powder in the catalyst layer. The values are shown respectively.

[Example 1 (Example)]
21.6 g of a catalyst (made by N.E. Chemcat, hereinafter referred to as catalyst 1) supported so that platinum is contained in a carbon support (specific surface area 800 m ² / g) in 50% of the total mass of the catalyst is added to 11.6 g of distilled water. Added and stirred well. On the other hand, HALS (ADK STAB LA57: Asahi) represented by CH ₂ (COOR) CH (COOR) CH (COOR) CH ₂ COOR (where R is 2,2,6,6-tetramethyl-4-piperidyl group) Denka Kogyo Co., Ltd. trade name, molecular weight: 792, number of basic nitrogen atoms: 4, insoluble in water) 7.9 g of a solution of 0.15 g dissolved in ethanol was added. This mixture was mixed and dispersed using a homogenizer (Kinematica trade name: Polotron). On the other hand, CF ₂ = CF ₂ / CF ₂ = CFOCF ₂ CF (CF ₃ ) O (CF ₂ ) ₂ SO ₃ H copolymer (ion exchange capacity 1.1 meq / g dry resin, hereinafter, 8 g of a liquid having a solid content concentration of 10% by mass dispersed in ethanol and 3.3 g of distilled water are added and mixed and dispersed using a homogenizer, and this is mixed with a coating liquid a for forming a catalyst layer a. It was.

The coating liquid a was applied onto a polypropylene substrate film with a bar coater, and then dried in an oven at 80 ° C. for 30 minutes to prepare a catalyst layer a. Table 1 shows the content of HALS contained in the catalyst layer. In addition, when the amount of platinum per unit area contained in the catalyst layer a was calculated by measuring the mass of only the base film before the formation of the catalyst layer a and the mass of the base film after the formation of the catalyst layer a, 0. It was 5 mg / cm ² .

Next, as a solid polymer electrolyte membrane, an ion exchange membrane (Flemion: trade name of Asahi Glass Co., Ltd., ion exchange capacity 1.1 milliequivalent / g dry resin) made of a perfluorocarbon polymer having a sulfonic acid group is used. The catalyst layers a formed on the base film were respectively disposed on both sides of the membrane and transferred by a hot press method. Thus, an anode catalyst layer and a cathode catalyst layer were formed, and a membrane / catalyst layer assembly comprising a solid polymer membrane having an electrode area of 25 cm ² and a catalyst layer was produced.

The obtained membrane / catalyst layer assembly was sandwiched between two gas diffusion layers made of carbon cloth having a thickness of 350 μm to produce a membrane / electrode assembly. Solid polymer fuel cell built in a power generation cell, supplying hydrogen (utilization rate 70%) / air (utilization rate 40%) at normal pressure and a cell temperature of 70 ° C. and a current density of 0.2 A / cm ² Was evaluated. Hydrogen and air were humidified and supplied to the cell with a dew point of 70 ° C. on the anode side and a dew point of 50 ° C. on the cathode side, and the cell voltage at the initial stage of operation was measured. The results are shown in Table 2. Furthermore, when the relationship between the elapsed time after the start of operation and the cell voltage (durability evaluation) is measured, it is as shown in Table 2.

[Example 2 (comparative example)]
A catalyst layer forming coating solution b was prepared in the same manner as in Example 1 except that ethanol in which HALS was not dissolved was used in place of the HALS ethanol solution. A catalyst layer b was produced in the same manner as in Example 1 except that the coating liquid b was used in place of the coating liquid a. When the amount of platinum per unit area contained in the catalyst layer b was measured in the same manner as in Example 1, it was 0.5 mg / cm ² . Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² was produced in the same manner as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer were constituted by the catalyst layer b.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was produced in the same manner as in Example 1, and the cell voltage at the initial stage of operation was measured in the same manner as in Example 1. The results are shown in Table 2. Furthermore, Table 2 shows the results obtained when durability evaluation is performed in the same manner as in Example 1.

[Example 3 (Example)]
In Example 1, instead of ADK STAB LA57 as HALS, HALS (ADK STAB LA77: Asahi Denka Kogyo Co., Ltd.) represented by ROC (= O) C ₈ H ₁₆ C (═O) OR (where R is the same as R in Example 1) A catalyst layer forming coating solution c was prepared in the same manner as in Example 1 except that the product name, molecular weight: 481, number of basic nitrogen atoms: 2, insoluble in water were used. A catalyst layer c was produced in the same manner as in Example 1 except that the coating liquid c was used instead of the coating liquid a. Table 1 shows the content of HALS contained in the catalyst layer. In addition, when the amount of platinum per unit area contained in the catalyst layer c was measured in the same manner as in Example 1, it was 0.5 mg / cm ² . Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² was produced in the same manner as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer were constituted by the catalyst layer c.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was produced in the same manner as in Example 1, and the cell voltage at the initial stage of operation was measured in the same manner as in Example 1. The results are shown in Table 2. Furthermore, Table 2 shows the results obtained when durability evaluation is performed in the same manner as in Example 1.

[Example 4 (Example)]
In Example 1, poly [{6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2) instead of ADK STAB LA57 as HALS , 6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}] (Timasorb 944: trade name, molecular weight of Ciba Specialty Chemicals) : 2500, the number of basic nitrogen atoms: 20, insoluble in water) was prepared in the same manner as in Example 1 except for dissolving 0.1 g of catalyst layer forming coating solution d. A catalyst layer d was prepared in the same manner as in Example 1 except that the coating liquid d was used in place of the coating liquid a. Table 1 shows the content of HALS contained in the catalyst layer. In addition, when the amount of platinum per unit area contained in the catalyst layer d was measured in the same manner as in Example 1, it was 0.5 mg / cm ² . Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² was produced in the same manner as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer were constituted by the catalyst layer d.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was produced in the same manner as in Example 1, and the cell voltage at the initial stage of operation was measured in the same manner as in Example 1. The results are shown in Table 2. Furthermore, Table 2 shows the results obtained when durability evaluation is performed in the same manner as in Example 1.

[Example 5 (Example)]
In Example 1, instead of ADK STAB LA57 as HALS, N, N′-bis (3-aminopropyl) ethylenediamine · 2,4-bis [N-butyl-N- (1,1,2,2,6,6- Pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate (Timasorb 119: trade name of Ciba Specialty Chemicals, molecular weight: 2000, number of basic nitrogen atoms: 20, A catalyst layer forming coating solution e was prepared in the same manner as in Example 1 except that 0.1 g of (insoluble in water) was dissolved. A catalyst layer e was produced in the same manner as in Example 1 except that the coating liquid e was used instead of the coating liquid a. Table 1 shows the content of HALS contained in the catalyst layer. In addition, when the amount of platinum per unit area contained in the catalyst layer e was measured in the same manner as in Example 1, it was 0.5 mg / cm ² . Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² was produced in the same manner as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer were constituted by the catalyst layer e. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² was produced in the same manner as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer were constituted by the catalyst layer e.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was produced in the same manner as in Example 1, and the cell voltage at the initial stage of operation was measured in the same manner as in Example 1. The results are shown in Table 2. Furthermore, Table 2 shows the results obtained when durability evaluation is performed in the same manner as in Example 1.

[Example 6 (Example)]
7.5 g of catalyst 1 is taken and added to a mixed solvent of 67 g of distilled water and 68 g of methanol and mixed well. To this, 7.9 g of a solution in which Adeka Stab LA77 is dissolved in 0.5 g of methanol is added as HALS, and this mixture is mixed and dispersed using a homogenizer.
Next, 2.08 g of sodium styrenesulfonate, 0.21 g of divinylbenzene, and 0.002 g of azobisisobutyronitrile are mixed into this mixture and mixed and dispersed with a homogenizer to prepare a coating solution f for forming a catalyst layer. .

This coating solution f is coated on a polypropylene substrate film with a bar coater, and then dried in a dryer at 80 ° C. for 8 hours, whereby styrene / divinylbenzene ion exchange having —SO ₃ Na group is performed. A catalyst layer f made of resin and having a platinum amount of 0.5 mg / cm ² per unit area is prepared. This catalyst layer f is washed several times with water and then immersed in a 0.5 mmol / L sulfuric acid aqueous solution to convert —SO ₃ Na groups into —SO ₃ H groups. Table 3 shows the content of HALS contained in the catalyst layer. The amount of platinum per unit area contained in the catalyst layer f can be calculated by measuring in the same manner as in Example 1.

Next, as a solid polymer electrolyte membrane, a 50 μm-thick polymer electrolyte membrane (polystyrene sulfonic acid graft-poly (ethylene · ethylene) synthesized by the method disclosed in Example 1 of JP-A-2002-334702 is used. A membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced in the same manner as in Example 1 except that tetrafluoroethylene)) is used.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 4 were obtained. Is obtained.

[Example 7 (comparative example)]
In Example 6, instead of using a HALS methanol solution, the same operation as in Example 6 was performed except that methanol that did not dissolve HALS was used to prepare a coating solution g for forming a catalyst layer. In Example 6, the coating liquid g is used in place of the coating liquid f, and a catalyst layer g having an amount of platinum of 0.5 mg / cm ² per unit area is produced in the same manner as in Example 6. This catalyst layer g is operated in the same manner as in Example 6 to convert —SO ₃ Na groups into —SO ₃ H groups. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced by performing the same operation as in Example 6 except that both the anode catalyst layer and the cathode catalyst layer are composed of the catalyst layer g.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 4 were obtained. Is obtained.

[Example 8 (Example)]
In Example 6, as a solid polymer electrolyte membrane, a 60 μm thick polymer electrolyte membrane (sulfonated polyethersulfone, ion exchange) obtained by synthesis by the method disclosed in Example 1 of JP-A No. 2001-307752 A membrane / catalyst layer assembly having an electrode area of 25 cm ² is prepared in the same manner as in Example 6 except that (volume: 0.56 meq / g dry resin) is used. Table 1 shows the content of HALS contained in the catalyst layer.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 4 were obtained. Is obtained.

[Example 9 (comparative example)]
In the same manner as in Example 7, a catalyst layer g is prepared. Next, an operation is performed in the same manner as in Example 8 except that both the anode catalyst layer and the cathode catalyst layer are constituted by the catalyst layer g, and a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 4 were obtained. Is obtained.

[Example 10 (Example)]
In the same manner as in Example 6, 7.5 g of catalyst 1 is taken and added to a mixed solvent of 67 g of distilled water and 68 g of methanol and mixed well. To this, 7.9 g of a solution in which Adeka Stab LA77 is dissolved in 0.5 g of methanol is added as HALS, and this mixture is mixed and dispersed using a homogenizer.

Then, this mixture was added to CF ₂ ═CF (CH ₂ CH ₂ CH ₃ ) / CF ₂ ═CF (CH ₂ CH ₂ SO ₃ H) copolymer (ion exchange capacity: 1.4 meq / g dry resin, Hereinafter, 3 g of copolymer B) is added and mixed and dispersed with a homogenizer to prepare a catalyst layer forming coating solution h. The copolymer can be obtained by synthesis by the method disclosed in Example 1 of JP-A No. 2004-10744, and 4-bromo-1,1,2-trifluorobutene-1 and 1 After adding isobutene to a freon solution with 1,2,2-trifluoropentene-1, a reaction is carried out by performing Co-γ irradiation for 6 hours to form a polymer, and sodium sulfite is added. It is obtained by introducing a —SO ₃ H group by reaction.

Next, in Example 6, the amount of platinum per unit area was 0 as in Example 6, except that the coating liquid h was used in place of the coating liquid f and the coating liquid h was dried in an oven at 80 ° C. for 30 minutes. A catalyst layer h of 5 mg / cm ² is prepared. Table 3 shows the content of HALS contained in the catalyst layer. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced by performing the same operation as in Example 6 except that both the anode catalyst layer and the cathode catalyst layer are constituted by the catalyst layer h.

Subsequently, as a solid polymer electrolyte membrane, a 40 μm polymer electrolyte membrane (sulfonated polyimide, ion exchange capacity: 1.21 mm) obtained by synthesis by the method disclosed in Comparative Example 2 of JP-A-2003-68327. The membrane / catalyst layer assembly having an electrode area of 25 cm ² is prepared in the same manner as in Example 6 except that equivalent weight / g dry resin) is used.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 4 were obtained. Is obtained.

[Example 11 (comparative example)]
In Example 10, instead of the HALS methanol solution, the same operation as in Example 10 was performed except that methanol that did not dissolve HALS was used to prepare catalyst layer forming coating solution i. In Example 10, the coating liquid i is used in place of the coating liquid h, and a catalyst layer i having an amount of platinum per unit area of 0.5 mg / cm ² is produced in the same manner as in Example 6. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² can be produced by performing the same operation as in Example 6 except that both the anode catalyst layer and the cathode catalyst layer are constituted by the catalyst layer i. . Table 3 shows the content of HALS contained in the catalyst layer.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 4 were obtained. Is obtained.

[Example 12 (Example)]
In Example 6, a catalyst layer-forming coating solution j is prepared in the same manner as in Example 6 except that a solution prepared by mixing 0.41 g of ADK STAB LA57 and 7.9 g of methanol is used as HALS. Except that the coating liquid j is used in place of the coating liquid f, an operation is performed in the same manner as in Example 6 to produce a catalyst layer j having an amount of platinum of 0.5 mg / cm ² per unit area. This catalyst layer j is operated in the same manner as in Example 6 to convert —SO ₃ Na groups into —SO ₃ H groups. Next, an operation is performed in the same manner as in Example 6 except that both the anode catalyst layer and the cathode catalyst layer are constituted by the catalyst layer j, and a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced. Table 3 shows the content of HALS contained in the catalyst layer.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 4 were obtained. Is obtained.

Example 13 (Example)
A catalyst layer forming coating solution k is prepared in the same manner as in Example 6 except that a solution prepared by mixing 0.43 g of chimasorb 944 and 7.9 g of methanol is used as HALS. Except that the coating liquid k is used in place of the coating liquid f, an operation is performed in the same manner as in Example 6 to produce a catalyst layer k having a platinum amount of 0.5 mg / cm ² per unit area. This catalyst layer k is operated in the same manner as in Example 6 to convert —SO ₃ Na groups into —SO ₃ H groups. Table 3 shows the content of HALS contained in the catalyst layer. Next, an operation is performed in the same manner as in Example 6 except that both the anode catalyst layer and the cathode catalyst layer are constituted by the catalyst layer k, and a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 4 were obtained. Is obtained.

Example 14 (Example)
2 g of catalyst 1 is taken and added to 11.6 g of distilled water, and stirred well. To this was added 7.9 g of a solution obtained by dissolving 0.2 g of tri-n-octylamine (molecular weight: 353.67, number of basic nitrogen atoms: 1, insoluble in water) in ethanol. The mixed solution is mixed and dispersed using a homogenizer. Copolymer A is dispersed in ethanol to obtain 8 g of a liquid having a solid content of 10% by mass, 3.3 g of distilled water is added, and further mixed and dispersed using a homogenizer to form a coating for forming a catalyst layer. Adjust liquid l.
This coating liquid l is coated on a polypropylene base film with a bar coater and dried in an oven at 80 ° C. for 30 minutes, so that the amount of platinum per unit area is 0.5 mg / cm ^2. The catalyst layer 1 is prepared. Table 5 shows the amine content contained in the catalyst layer. The amount of platinum per unit area contained in the catalyst layer 1 can be calculated by measuring in the same manner as in Example 1.

Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced by performing the same operation as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer are composed of the catalyst layer l.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

Example 15 (Example)
Example 14 is the same as Example 14 except that 0.1 g of diisobutylamine (molecular weight: 129.14, number of basic nitrogen atoms: 1, solubility in water <1) is used instead of tri-n-octylamine. The operation is carried out to prepare a catalyst layer forming coating solution m. Using the coating liquid m instead of the coating liquid l, a catalyst layer m having a platinum amount of 0.5 mg / cm ² per unit area is prepared in the same manner as in Example 14. Table 5 shows the amine content contained in the catalyst layer. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced by performing the same operation as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer are composed of the catalyst layer n.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

Example 16 (Example)
In Example 14, 0.1 g of 2-ethylhexylamine (molecular weight: 129.24, number of basic nitrogen atoms: 1, solubility in water: 0.16) was used instead of tri-n-octylamine. The same operation as in Example 14 is carried out to prepare catalyst layer forming coating solution n. Using the coating liquid n instead of the coating liquid l, a catalyst layer n having a platinum amount of 0.5 mg / cm ² per unit area is prepared in the same manner as in Example 14. Table 5 shows the amine content contained in the catalyst layer. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced by performing the same operation as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer are composed of the catalyst layer n.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

[Example 17 (comparative example)]
Example 14 except that 0.05 g of piperidine (molecular weight: 85.2, number of basic nitrogen atoms: 1, solubility in water: soluble at an arbitrary ratio) is used instead of tri-n-octylamine in Example 14. The same operation as in No. 14 is performed to prepare a catalyst layer forming coating solution o. Using the coating liquid o instead of the coating liquid l, a catalyst layer o having an amount of platinum of 0.5 mg / cm ² per unit area is prepared in the same manner as in Example 14. Table 5 shows the amine content contained in the catalyst layer. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced by performing the same operation as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer are composed of the catalyst layer o.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

[Example 18 (comparative example)]
In Example 14, 0.05 g of n-propylamine (molecular weight: 59.11, number of basic nitrogen atoms: 1, solubility in water: 100) was used instead of tri-n-octylamine. In the same manner as described above, a catalyst layer forming coating solution p is prepared. Using the coating liquid p instead of the coating liquid l, a catalyst layer p having a platinum amount of 0.5 mg / cm ² per unit area is prepared in the same manner as in Example 14. Table 5 shows the amine content contained in the catalyst layer. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is manufactured by performing the same operation as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer are constituted by the catalyst layer p.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

[Example 19 (comparative example)]
In Example 14, 0.1 g of N, N-dimethylaminopropylamine (molecular weight: 102.18, the number of basic nitrogen atoms: 2, solubility: 100) was used instead of tri-n-octylamine. The same operation as in Example 14 is performed to prepare a catalyst layer forming coating solution q. Using the coating liquid q instead of the coating liquid l, a catalyst layer q having an amount of platinum per unit area of 0.5 mg / cm ² is prepared in the same manner as in Example 14. Table 5 shows the amine content contained in the catalyst layer. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced by performing the same operation as in Example 1 except that both the anode catalyst layer and the cathode catalyst layer are constituted by the catalyst layer q.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

[Example 20 (Example)]
In Example 14, instead of using the copolymer A, 0.55 g of sodium styrenesulfonate, 0.055 g of divinylbenzene, and 0.0055 g of azobisisobutyronitrile were mixed to form a coating solution r for forming a catalyst layer. Adjust.

In Example 14, the coating liquid r was used in place of the coating liquid l, and the same operation was performed except that the coating liquid r was dried in an oven at 80 ° C. for 8 hours. A styrene / divinylbenzene ion having a —SO ₃ Na group was used. A catalyst layer r containing an exchange resin and containing 0.5 mg / cm ² of platinum per unit area is prepared. The catalyst layer r is washed several times with water and then immersed in a 0.5 mmol / L sulfuric acid aqueous solution to convert —SO ₃ Na groups into —SO ₃ H groups. Table 5 shows the amine content contained in the catalyst layer.

Next, as a solid polymer electrolyte membrane, a 50 μm-thick polymer electrolyte membrane (polystyrene sulfonic acid graft-poly (ethylene · ethylene) synthesized by the method disclosed in Example 1 of JP-A-2002-334702 is used. A membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced in the same manner as in Example 1 except that (tetrafluoroethylene) is used.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

[Example 21 (comparative example)]
In Example 20, instead of the ethanol solution of tri-n-octylamine, the same procedure as in Example 20 was used except that ethanol that did not dissolve tri-n-octylamine was used. To prepare. Using the coating liquid s instead of the coating liquid r, a catalyst layer s having a platinum amount of 0.5 mg / cm ² per unit area is prepared in the same manner as in Example 20. This catalyst layer s is operated in the same manner as in Example 20 to convert —SO ₃ Na groups into —SO ₃ H groups. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced by performing the same operation as in Example 20 except that both the anode catalyst layer and the cathode catalyst layer are composed of the catalyst layer s.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

[Example 22 (Example)]
In Example 14, instead of using the copolymer A, 0.8 g of the copolymer B and 7.2 g of ethanol are added to prepare a coating liquid t for forming a catalyst layer.

Next, in Example 14, the coating liquid t is used in place of the coating liquid l, and a catalyst layer t having an amount of platinum of 0.5 mg / cm ² per unit area is produced in the same manner as in Example 14. Table 5 shows the amine content contained in the catalyst layer. Next, the anode catalyst layer and the cathode catalyst layer are both constituted by the catalyst layer t, and a 40 μm polymer obtained by synthesizing by the method disclosed in Example 2 of JP-A-2003-68327 is used as the solid polymer electrolyte membrane. A membrane / catalyst layer assembly having an electrode area of 25 cm ² is prepared in the same manner as in Example 1 except that the electrolyte membrane (sulfonated polyimide) is used.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

[Example 23 (comparative example)]
In Example 22, the same operation as in Example 22 was carried out except that ethanol that did not dissolve tri-n-octylamine was used in place of the ethanol solution of tri-n-octylamine. Adjust. In Example 22, the coating liquid u is used in place of the coating liquid t, and a catalyst layer u having a platinum amount of 0.5 mg / cm ² per unit area is produced in the same manner as in Example 14. Next, a membrane / catalyst layer assembly having an electrode area of 25 cm ² is produced by performing the same operation as in Example 22 except that both the anode catalyst layer and the cathode catalyst layer are constituted by the catalyst layer u.
Using this membrane / catalyst layer assembly, a membrane / electrode assembly was prepared in the same manner as in Example 1. When the cell voltage was measured and the durability was evaluated in the initial operation in the same manner as in Example 1, the results shown in Table 6 were obtained. Is obtained.

  According to the present invention, since an amine is contained in the catalyst layer, hydrogen peroxide and peroxide radicals are less likely to be generated. Therefore, the fuel cell incorporating the obtained membrane-electrode assembly is capable of generating power for a long period of time. Also reduces performance degradation. Therefore, it is possible to provide a membrane / electrode assembly for a polymer electrolyte fuel cell that is stable even when power is generated for a long time.

Claims (10)

An anode and a cathode having a catalyst layer containing a catalyst powder in which catalytic metal particles are supported on a carbon support and an ion exchange resin; an ion exchange membrane disposed between the catalyst layer of the anode and the catalyst layer of the cathode; And at least one of the catalyst layer of the anode and the catalyst layer of the cathode contains an amine having a solubility in water of 3 or less at 20 ° C. Content (W × N) / M × 1000 of the amine with respect to the catalyst powder is 0.03 to 1 (W is the content (g) of the amine per 1 g of the catalyst powder, and M is the molecular weight of the amine) , N is the number of basic nitrogen atoms in one molecule of the amine.) A membrane / electrode assembly for a polymer electrolyte fuel cell, wherein: An anode and a cathode having a catalyst layer containing a catalyst powder in which catalytic metal particles are supported on a carbon support and an ion exchange resin; an ion exchange membrane disposed between the catalyst layer of the anode and the catalyst layer of the cathode; And at least one of the catalyst layer of the anode and the catalyst layer of the cathode contains an amine having a solubility in water of 3 or less at 20 ° C. A membrane / electrode assembly for a polymer electrolyte fuel cell, wherein the content of the amine with respect to the catalyst powder is 0.3 to 30% by mass. The membrane / electrode assembly for a polymer electrolyte fuel cell according to claim 1 or 2, wherein the amine is HALS having a group represented by Formula 1 (where X represents a hydrogen atom or a methyl group).

The amine is 2-ethylhexylamine, 3- (2-ethylhexyloxy) propylamine, diisobutylamine, di-n-octylamine, tri-n-octylamine, triallylamine, di-2-ethylhexylamine and 3- ( The membrane / electrode assembly for a polymer electrolyte fuel cell according to claim 1 or 2, which is at least one selected from the group consisting of dibutylamino) propylamine. The mass ratio of the catalyst metal to the carbon support (catalyst metal: carbon support) in the catalyst powder is 2: 8 to 7: 3, and the carbon support is composed of carbon black, activated carbon, carbon nanotubes, and carbon nanohorns. The membrane / electrode assembly for a polymer electrolyte fuel cell according to any one of claims 1 to 4, which is at least one selected from the group. The ion exchange _{resin, CF 2 = CF- (OCF 2} CFX) m -O p - (CF 2) a perfluorovinyl compound represented by n -SO ₃ H (m is an integer of 0 to 3, n Represents an integer of 1 to 12, p represents 0 or 1, and X represents a fluorine atom or a trifluoromethyl group.) And a copolymer comprising a repeating unit based on tetrafluoroethylene. A membrane / electrode assembly for a polymer electrolyte fuel cell according to any one of claims 1 to 5. An anode and a cathode having a catalyst layer containing a catalyst powder in which catalytic metal particles are supported on a carbon support and an ion exchange resin; an ion exchange membrane disposed between the catalyst layer of the anode and the catalyst layer of the cathode; A membrane / electrode assembly for a polymer electrolyte fuel cell comprising the catalyst powder, the ion exchange resin, and an amine having a solubility in water of 3 or less at 20 ° C., and Content (W × N) / M × 1000 with respect to the catalyst powder is 0.03 to 1 (W is content (g) per 1 g of catalyst powder of the amine, M is molecular weight of the amine, N Is the number of basic nitrogen atoms in one amine molecule.) A catalyst layer was formed by preparing a coating solution and coating the coating solution on a substrate. Layer anode and cathode A method for producing a membrane / electrode assembly for a polymer electrolyte fuel cell, comprising at least one of the catalyst layers. An anode and a cathode having a catalyst layer containing a catalyst powder in which catalytic metal particles are supported on a carbon support and an ion exchange resin; an ion exchange membrane disposed between the catalyst layer of the anode and the catalyst layer of the cathode; A membrane / electrode assembly for a polymer electrolyte fuel cell comprising the catalyst powder, the ion exchange resin, and an amine having a solubility in water of 3 or less at 20 ° C., and A catalyst layer is formed by preparing a coating liquid having a content by mass ratio of 0.3 to 30% with respect to the catalyst powder, and coating the coating liquid on a substrate. A method for producing a membrane / electrode assembly for a polymer electrolyte fuel cell, wherein at least one of a catalyst layer of an anode and a cathode is used. The membrane-electrode assembly for a polymer electrolyte fuel cell according to claim 7 or 8, wherein the amine is HALS having a group represented by Formula 1 (where X represents a hydrogen atom or a methyl group). Production method.

The amine is 2-ethylhexylamine, 3- (2-ethylhexyloxy) propylamine, diisobutylamine, di-n-octylamine, tri-n-octylamine, triallylamine, di-2-ethylhexylamine and 3- ( 9. The method for producing a membrane / electrode assembly for a polymer electrolyte fuel cell according to claim 7 or 8, which is at least one selected from the group consisting of dibutylamino) propylamine.

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