JP2008270176A - Membrane-electrode assembly and fuel cell using the same - Google Patents

Abstract

An inexpensive membrane-electrode assembly and a fuel cell using the same are provided.
A membrane-electrode assembly comprising a catalyst layer containing an electrode catalyst on both sides of an electrolyte membrane, wherein at least one of the catalyst layers contains a non-noble metal-based electrode catalyst, and the electrolyte membrane is a hydrocarbon. A membrane-electrode assembly which is a system electrolyte membrane.
[Selection figure] None

Description

  The present invention relates to a membrane-electrode assembly and a fuel cell using the same. More specifically, the present invention relates to a membrane-electrode assembly having a non-noble metal-based electrode catalyst and a hydrocarbon-based electrolyte membrane, and the same. Relates to the fuel cell.

Currently, platinum is generally used as an electrode catalyst in solid polymer fuel cells and direct methanol fuel cells that are being developed for practical use. However, there are problems such as the high cost of platinum and the possibility that resources will be depleted in the future due to limited reserves.
As an example of using a catalyst that replaces platinum as an electrode catalyst of a fuel cell, for example, Patent Document 1 describes a membrane-electrode assembly using palladium as an electrode catalyst. Non-Patent Document 1 discloses a membrane-electrode assembly using ruthenium as an electrode catalyst.
However, the electrode catalysts as disclosed in Patent Document 1 and Non-Patent Document 1 are both noble metals, and it is expected that it is difficult to secure a stable supply in the future like platinum.

  As an example of using an electrode catalyst other than the noble metal, for example, Non-Patent Document 2 describes a membrane-electrode assembly using a cobalt / pyrrole / carbon composite as an electrode catalyst. Non-Patent Document 3 describes a membrane-electrode assembly using hemoglobin carbide as an electrode catalyst.

Each of the membrane-electrode assemblies uses a fluorine-based electrolyte membrane represented by a Nafion membrane (registered trademark), and the fluorine-based electrolyte membrane has a problem that the price is high because fluorine is used. there were.
Further, with the use of a fluorine-based electrolyte membrane as a member of a fuel cell, there is a problem that fluorine ions are eluted from the membrane to cause deterioration of the membrane or corrosion of members other than the fuel cell membrane. The membrane-electrode assembly using this membrane has not yet been sufficiently stable.
JP 2006-260909 A “Journal of Power Sources”, Vol.153, p.11-17 (2006) “Nature”, Vol.443, p.63-66 (2006) “Chemistry of Materials”, Vol.18, No.5, p.1303-1311 (2006)

  An object of the present invention is to provide a membrane-electrode assembly that is inexpensive and excellent in stability, and a fuel cell using the membrane-electrode assembly.

The problems of the present invention have been solved by the following means.
[1] A membrane-electrode assembly having a catalyst layer containing an electrode catalyst on both sides of an electrolyte membrane, wherein at least one of the catalyst layers contains a non-noble metal-based electrode catalyst, and the electrolyte membrane is a hydrocarbon type A membrane-electrode assembly, which is an electrolyte membrane.
[2] The membrane-electrode assembly according to the above [1], wherein the non-noble metal-based electrode catalyst is an electrode catalyst using a non-noble metal complex.
[3] The membrane-electrode assembly according to [1] or [2], wherein the hydrocarbon-based electrolyte membrane contains an aromatic hydrocarbon-based polymer electrolyte.
[4] The membrane-electrode junction according to any one of [1] to [3], wherein the hydrocarbon electrolyte membrane is an aromatic hydrocarbon electrolyte membrane having proton conductivity. body.
[5] A fuel cell comprising the membrane-electrode assembly according to any one of [1] to [4].

  The membrane-electrode assembly of the present invention uses a non-noble metal-based electrode catalyst and a hydrocarbon-based electrolyte membrane, so that the production cost of the membrane-electrode assembly can be greatly reduced, and the stability is excellent. Therefore, the fuel cell using the joined body can reduce the cost and is excellent in stability.

Hereinafter, the present invention will be described in detail.
[Membrane-electrode assembly]
The membrane-electrode assembly (hereinafter also referred to as “MEA”) of the present invention includes a catalyst layer containing an electrode catalyst on both sides of an electrolyte membrane, and at least one of the catalyst layers is non-noble metal-based. An electrode catalyst is included, and the electrolyte membrane is a hydrocarbon-based electrolyte membrane.

(Electrode catalyst)
The non-noble metal-based electrode catalyst in the membrane-electrode assembly of the present invention is an electrode catalyst that does not contain a non-noble metal element as a catalyst component. A noble metal element means gold, silver, ruthenium, rhodium, palladium, osmium, iridium, and platinum as described in the physics and chemistry dictionary (5th edition, 3rd printing, 1998, Iwanami Shoten). Therefore, the non-noble metal-based electrode catalyst of the present invention is composed of elements excluding the noble metal elements, that is, transition elements and / or typical elements.

As the electrode catalyst used in the present invention, the cathode (oxygen electrode or air electrode) electrode catalyst is a material having a catalytic action for the following oxygen reduction reaction.
O ₂ + 4H ⁺ + 4e ⁻ → 2H ₂ O

  Examples of the material having a catalytic action with respect to the above reaction include, for example, JP-A No. 2006-59578, PAVigato, S. Tamburini, “Coordination Chemistry Reviews”, Vol. 248, p. 1717-2128 (2004), Tatsuhiro. Okada et al., “Journal of Inorganic and Organometallic Polymers”, Vol. 9, No. 4, p. 199-219 (1999), etc., and heat treated products of metal complexes, JP 2006-504232 A Heat treated product of metal ion-supported polymer described in Japanese Patent Application Publication No. 2005-161203, Metal Oxynitride described in Japanese Patent Application Publication No. 2005-161203, Japanese Patent Application Publication No. 2004-95263, Japanese Patent Application Publication No. 2005-50759 Metal oxides described in JP-A-2003-249231, carbon materials mainly containing non-graphitizable carbon, JP-A-2004-330181, etc. Examples thereof include nitrogen-containing activated carbides, carbon alloy fine particles doped with nitrogen atoms and / or boron atoms described in JP-A No. 2004-362802, and the like.

  The cathode electrode catalyst may be used alone or as a composite material in which a plurality of materials are combined. The form of use is not particularly limited as long as the function is not lost, but it is supported on a carbon carrier such as carbon black or carbon nanotube, an acid-resistant metal oxide such as titanium oxide, or a conductive polymer. It is preferable to use them.

  As the cathode electrode catalyst, a material having high oxygen reduction activity is preferably used. Examples of such materials include metal complexes, heat-treated metal complexes, heat-treated products of metal ion-supported polymers, metal oxynitrides, and metal oxides. More preferably, metal complexes, heat-treated products of metal complexes, metals A heat-treated product of an ion-supported polymer, particularly preferably a metal complex and a heat-treated product of a metal complex.

Examples of the metal complexes include Michinori Oki et al., “Chemical Dictionary” (1st edition, 1994, Tokyo Kagaku Dojin) page 142, Werner complex described in page 1117, Non-Werner complex described in page 1117, Polymer Society of Japan The metal complexes described in pages 103 to 112 of “Fuel Cell and Polymer” edited by Fuel Cell Material Research Group (Kyoritsu Shuppan, published on November 10, 2005, Kyoritsu Shuppan) can be used. In particular, the use of a metal complex having an organic compound having an aromatic ring structure such as pyridine, phenanthroline, pyrrole or phenol as a ligand is preferable because the catalytic activity is improved. Examples of the metal complex include metal complexes represented by the following formulas (X-1) to (X-15). More preferred are (X-1) to (X-12), and particularly preferred are (X-1) to (X-7). The hydrogen atom of the ligand of the metal complex in the formula is substituted with an alkyl group such as a methyl group, an ethyl group or a butyl group, a halogeno group such as a chloro group or a bromo group, or an aromatic group such as a phenyl group or a pyridyl group. May be. M ¹ and M ² in the formula represent a metal atom belonging to a non-noble metal element. M ¹ and M ² may be the same as or different from each other. In the formula, the charge of the complex is omitted.

  The heat-treated product of the metal complex is a metal complex obtained by heat-treating the metal complex in an inert gas atmosphere such as nitrogen, and the temperature during the heat treatment is preferably 250 ° C. or more, more preferably 300 ° C or higher, more preferably 400 ° C or higher, particularly preferably 500 ° C or higher. Moreover, the upper limit of the temperature concerning heat processing becomes like this. Preferably it is 1500 degrees C or less, More preferably, it is 1200 degrees C or less, Most preferably, it is 1000 degrees C or less. The apparatus for performing the heat treatment is not particularly limited, and a tubular furnace, oven, furnace, IH hot plate, or the like can be used.

  As the metal element contained in the cathode electrode catalyst, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, yttrium, zirconium, niobium, molybdenum, cadmium, indium, tin, antimony, Examples include tellurium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, hafnium, tantalum, tungsten, rhenium, and the like.

More preferably, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, yttrium, zirconium, niobium, molybdenum, lanthanum, cerium, praseodymium, neodymium, samarium, hafnium, tantalum, tungsten More preferably vanadium, chromium, manganese, iron, cobalt, nickel, copper, zirconium, niobium, molybdenum, tantalum and tungsten.
Among these, an element selected from the group consisting of vanadium, chromium, manganese, iron, cobalt, nickel and copper is particularly preferable.

Further, as the electrode catalyst used in the present invention, the anode (fuel electrode) electrode catalyst is a material having a catalytic action for the oxidation reaction as shown below.
(When using hydrogen as fuel)
H ₂ → 2H ⁺ + 2e ⁻
(When using methanol as fuel)
CH ₃ OH + H ₂ O → CO ₂ + 6H ⁺ + 6e ⁻

  The fuel for the anode is not limited to hydrogen or methanol exemplified above, but also other alcohols having 2 to 10 carbon atoms such as ethanol and propanol, and 2 to 10 carbon atoms such as dimethyl ether and diethyl ether. Ethers, aldehydes having 1 to 5 carbon atoms such as formic acid and formaldehyde, hydrocarbons having 1 to 20 carbon atoms such as methane, ethane, and kerosene, and nitrogen-containing compounds such as ammonia, hydrazine, and ammonia borane. Can do.

  As the anode electrode catalyst, it is preferable to use a material having high catalytic activity for these oxidation reactions when hydrogen, alcohols, or ethers are used among the fuels exemplified above. Examples of such a material include, for example, JP 2006-59578 A, PAVigato, S. Tamburini, “Coordination Chemistry Reviews”, Vol. 248, p. 1717-2128 (2004), Tatsuhiro Okada et al., “ Journal of Inorganic and Organometallic Polymers ”, Vol.9, No.4, p.199-219 (1999), etc., described in JP 2004-31174 A, etc. Coordination polymer metal complexes, hydrated titanium oxides supporting metal complexes described in JP-A-60-31827, etc., metal ion-supporting polymers described in JP-T-2006-504232, etc. Heat treated material, molybdenum carbide described in “Electrochemical and Solid-State Letters”, Vol. 9, No. 3, p.A160-A162 (2006), and the like, described in JP-A No. 2006-12773, etc. Tungsten carbide, JP200 Metal oxides described in JP-A-5-50760, titanium borides described in JP-A 2006-120407, transition metal silicides described in JP-A 2005-310418, etc. Examples include heteropolyacids described in Japanese Unexamined Patent Publication No. 2004-241307.

  The anode electrode catalyst may be used alone or as a composite material in which a plurality of materials are combined. The form of use is not particularly limited as long as the function is not lost, but it is supported on a carbon carrier such as carbon black or carbon nanotube, an acid-resistant metal oxide such as titanium oxide, or a conductive polymer. It is preferable to use them. The metal element contained in the anode electrode catalyst is the same as described and exemplified as the metal element contained in the cathode electrode catalyst.

Further, the materials exemplified as the cathode electrode catalyst and the anode electrode catalyst are not limited to those for the cathode and the anode, respectively, and it is preferable to use the materials for the sites where the functions can be efficiently exhibited. Further, it is preferable that both the cathode electrode catalyst and the anode electrode catalyst are non-noble metal-based electrode catalysts. However, as long as the gist of the present invention is not lost, a part thereof includes a noble metal electrode catalyst such as platinum. It is more preferable to use a non-noble metal-based electrode catalyst on at least one of the cathode side and the anode side. When the amount of platinum in the catalyst layer is large, the cost for producing the fuel cell becomes high. Therefore, it is preferable that the amount of platinum in the catalyst layer is small. When the relationship P between the total mass of the non-noble metal-based electrocatalyst in the catalyst layer and the total mass of the non-noble metal-based electrocatalyst and platinum in the catalyst layer is defined as in the following formula (1):
P = (total mass of platinum in catalyst layer) / (total mass of non-noble metal electrode catalyst and platinum in catalyst layer) Formula (1)
The value of P is preferably 0.8 or less, more preferably 0.7 or less, still more preferably 0.6 or less, and particularly preferably 0.5 or less. The lower limit of P is 0.

(Electrolyte membrane)
In the present invention, a hydrocarbon-based electrolyte membrane having proton conductivity is preferably used as the hydrocarbon-based electrolyte membrane, which is usually composed of a hydrocarbon-based polymer electrolyte. Here, the “hydrocarbon polymer electrolyte” means a polymer electrolyte in which the content of halogen atoms such as fluorine atoms is 25% by mass or less (preferably 0 to 5% by mass) in the element mass composition ratio. To do. As the hydrocarbon-based polymer electrolyte, either a polymer electrolyte having an acidic group or a polymer electrolyte having a basic group can be applied. A polymer electrolyte having an acidic group is more preferable because a fuel cell having further excellent power generation performance can be obtained. Examples of the acidic group include a sulfonic acid group, a carboxylic acid group, a phosphonic acid group, a phosphinic acid group, a sulfonylimide group (—SO ₂ NHSO ₂ —), a phenolic hydroxyl group, and the like. Groups are more preferred, and sulfonic acid groups are particularly preferred.

  Representative examples of such hydrocarbon polymer electrolytes include, for example, (A) a polymer electrolyte in which a sulfonic acid group and / or a phosphonic acid group are introduced into a hydrocarbon polymer whose main chain is an aliphatic hydrocarbon; ) A polymer electrolyte in which a sulfonic acid group and / or a phosphonic acid group is introduced into a polymer having an aromatic ring in the main chain; (C) an inorganic unit structure such as an aliphatic hydrocarbon, a siloxane group, or a phosphazene group in the main chain. A polymer electrolyte in which a sulfonic acid group and / or phosphonic acid group is introduced into a polymer comprising: (D) the polymer before introduction of the sulfonic acid group and / or phosphonic acid group in (A) to (C) above; A polyelectrolyte obtained by introducing a sulfonic acid group and / or a phosphonic acid group into a copolymer composed of any two or more types of repeating units selected from repeating units; The hydrocarbon polymer containing atom, polymeric electrolytes introduced by ionic bonding of the acidic compound such as sulfuric acid or phosphoric acid.

  Examples of the polymer electrolyte (A) include polyvinyl sulfonic acid, polystyrene sulfonic acid, and poly (α-methylstyrene) sulfonic acid.

  The polymer electrolyte (B) may be one in which the main chain is interrupted by a hetero atom such as an oxygen atom. For example, polyether ether ketone, polysulfone, polyether sulfone, poly (arylene ether) ), Polyimide, poly ((4-phenoxybenzoyl) -1,4-phenylene), polyphenylene sulfide, polyphenylquinoxalene and other homopolymers each having a sulfonic acid group introduced therein, sulfoarylated polybenz Imidazole, sulfoalkylated polybenzimidazole, phosphoalkylated polybenzimidazole described in JP-A-9-110882, and the like; Appl. Polym. Sci. , 18, 1969 (1974) and the like, and phosphonated poly (phenylene ether).

  Examples of the polymer electrolyte (C) include Polymer Prep. , 41, no. 1, 70 (2000), in which a sulfonic acid group is introduced into the polyphosphazene, which can be easily produced according to the method for producing a polysiloxane having a phosphonic acid group.

  As the polymer electrolyte (D), a sulfonic acid group and / or a phosphonic acid group is introduced into a random copolymer, but a sulfonic acid group and / or a phosphonic acid group is introduced into an alternating copolymer. The sulfonic acid group and / or the phosphonic acid group may be introduced into the block copolymer. Examples of the sulfonic acid group introduced into the random copolymer include sulfonated polyethersulfone polymers described in JP-A-11-116679.

  Examples of the polymer electrolyte (E) include polybenzimidazole containing phosphoric acid described in JP-T-11-503262.

  Among the above polymer electrolytes, the polymer electrolyte (B) or (D) is preferable from the viewpoint of achieving both high power generation performance and durability.

Among these, from the viewpoint of heat resistance and ease of recycling, it is preferable that the hydrocarbon electrolyte membrane contains an aromatic polymer electrolyte. Examples of the aromatic polymer electrolyte include a polymer compound having an aromatic ring in the main chain of the polymer chain and an acidic group in the side chain and / or the main chain. As the aromatic polymer electrolyte, those soluble in a solvent are usually used, and an electrolyte membrane having a desired film thickness can be easily obtained by a known solution casting method.
Even if the acidic group of these aromatic polyelectrolytes is directly substituted on the aromatic ring constituting the main chain of the polymer, it is bonded to the aromatic ring constituting the main chain via a linking group. Or a combination thereof.

“Polymer having an aromatic ring in the main chain” means, for example, a polymer in which the main chain is connected to each other such as polyarylene or a divalent aromatic group is divalent. It is connected via the group of and constitutes the main chain. Examples of the divalent group include —O—, —S—, a carbonyl group, a sulfinyl group, a sulfonyl group, an amide group, an ester group, a carbonic acid ester group, an alkylene group having about 1 to 4 carbon atoms, and an alkyl group having 1 to 4 carbon atoms. And a fluorine-substituted alkylene group having about 2 to 4 carbon atoms, an alkenylene group having about 2 to 4 carbon atoms, and an alkynylene group having about 2 to 4 carbon atoms. In addition, aromatic groups include aromatic groups such as phenylene group, naphthalene group, atracenylene group, fluorenediyl group, pyridinediyl group, frangyl group, thiophenediyl group, imidazolyl group, indolediyl group, quinoxalinediyl group, etc. The aromatic heterocyclic group of these is mentioned.
Further, the divalent aromatic group may have a substituent in addition to the acidic group, and examples of the substituent include an alkyl group having 1 to 20 carbon atoms and an alkoxy group having 1 to 20 carbon atoms. Group, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, a nitro group, and a halogen atom. In addition, when it has a halogen atom as a substituent, or when it has a fluorine-substituted alkylene group as a divalent group linking the aromatic group, it is represented by the element mass composition ratio of the aromatic polymer electrolyte. The halogen atom is 25% by mass or less (preferably 0 to 5% by mass).

  As a preferred aromatic polymer electrolyte, when the aromatic polymer electrolyte is used as a membrane, a domain having an acidic group contributing to proton conductivity and an ion exchange group contributing to mechanical strength are substantially included. It is preferable to obtain a membrane having both domains not possessed, that is, a phase-separated, preferably microphase-separated membrane. The microphase separation structure here means, for example, a fine phase (microdomain) having a high density of the block (A) having an acidic group and an ion exchange group when viewed with a transmission electron microscope (TEM). A structure in which fine phases (microdomains) having a high density of blocks (B) that do not substantially exist are mixed, and the domain width of each microdomain structure, that is, the identity period is several nm to several hundred nm. Point to. Those having a microdomain structure of 5 nm to 100 nm are preferable. In addition, as an aromatic polymer electrolyte that easily obtains a membrane having such a microphase separation structure, a block copolymer or graft having both a block having an acidic group and a block having substantially no ion exchange group As a copolymer, these can be preferably used because microscopic phase separation in the order of molecular chain size is likely to occur due to chemical bonds between different polymer blocks. Of these, block copolymers are preferred.

  In the above preferred block copolymer, the “block having an ion exchange group” means a block containing an average of 0.5 or more ion exchange groups per one repeating unit constituting the block. It is more preferable that an average of 1.0 or more per repeating unit is included. On the other hand, “a block having substantially no ion exchange group” means a segment having an average of less than 0.5 ion exchange groups per repeating unit constituting such a block. The average per unit is preferably 0.1 or less, and more preferably 0.05 or less on average.

  As typical examples of particularly suitable block copolymers, for example, blocks and ions having an aromatic polyether structure described in JP-A-2005-126684 and JP-A-2005-139432 having an ion exchange group Although a block copolymer consisting of a block having substantially no exchange group can be mentioned, the block copolymer having a polyarylene block having an acidic group described in International Publication WO2006 / 95919 is, Since an electrolyte membrane that achieves ion conductivity and water resistance at a high level can be formed, a membrane-electrode assembly with more excellent power generation performance can be provided by a synergistic effect with the catalyst layer of the present invention.

  The molecular weight of the polymer electrolyte can be suitably determined within the optimum range depending on its structure and the like, and is preferably 1,000 to 1,000,000, expressed in terms of polystyrene-reduced number average molecular weight by GPC (gel permeation chromatography) method. The number average molecular weight is preferably 5,000 or more, particularly 10,000 or more, and is preferably 500,000 or less, particularly preferably 300,000 or less.

  Furthermore, the hydrocarbon-based electrolyte membrane according to the membrane-electrode assembly of the present invention contains other components in addition to the polymer electrolyte exemplified above, as long as the proton conductivity is not significantly reduced, depending on the desired properties. You may go out. Examples of such other components include additives such as plasticizers, stabilizers, mold release agents, and water retention agents that are used in ordinary polymers.

  In particular, during the operation of the fuel cell, peroxide is generated in the catalyst layer adjacent to the hydrocarbon electrolyte membrane, and this peroxide diffuses and changes into radical species, which constitutes the hydrocarbon electrolyte membrane. May deteriorate the polymer electrolyte. In order to avoid such inconvenience, it is preferable to add a stabilizer capable of imparting radical resistance to the polymer electrolyte. Suitable additives include stabilizers for enhancing chemical stability such as oxidation resistance and radical resistance. Examples of the stabilizer include additives as exemplified in JP-A No. 2003-201403, JP-A No. 2003-238678, or JP-A No. 2003-282096. Or the phosphonic acid group containing polymer described in Unexamined-Japanese-Patent No. 2005-38834 or Unexamined-Japanese-Patent No. 2006-66391 is mentioned.

  For the purpose of improving the mechanical strength of the electrolyte membrane, a composite membrane in which the polymer electrolyte and a predetermined support are combined can be used. Examples of the support include substrates such as a fibril shape and a porous membrane shape. The use of a thin hydrocarbon-based electrolyte membrane as the hydrocarbon-based electrolyte membrane used in the present invention is preferable because the resistance of the fuel cell can be reduced. The preferred film thickness is 200 μm or less, more preferably 150 μm or less, still more preferably 100 μm or less, and particularly preferably 50 μm or less. In addition, if the thickness of the hydrocarbon-based electrolyte membrane is too thin, gas cross-leakage tends to occur. Therefore, the thickness is preferably 1 μm or more, more preferably 3 μm or more, and particularly preferably 5 μm or more.

[Fuel cell]
Next, a preferred embodiment of a fuel cell including the above-described membrane-electrode assembly will be described in detail with reference to the accompanying drawings.
FIG. 1 is a longitudinal sectional view of a cell of a fuel cell according to a preferred embodiment of the present invention. As shown in FIG. 1, the fuel cell 10 includes a membrane-electrode assembly 20. The membrane-electrode assembly 20 includes the above-described hydrocarbon-based electrolyte membrane 12 (proton conducting membrane) and a pair of catalyst layers 14a and 14b sandwiching the membrane. The fuel cell 10 includes gas diffusion layers 16a and 16b and separators 18a and 18b, and the gas diffusion layers 16a and 16b and separators 18a and 18b are sequentially arranged on both sides of the membrane-electrode assembly 20 so as to sandwich them. Is formed.

The catalyst layers 14a and 14b adjacent to the hydrocarbon-based electrolyte membrane 12 in the membrane-electrode assembly 20 are layers that function as electrode layers in the fuel cell, and either one of them serves as an anode electrode layer and the other serves as a cathode electrode. Become a layer. The catalyst layers 14a and 14b are preferably formed from a catalyst composition containing the above-described hydrocarbon polymer electrolyte or a fluorine-based polymer electrolyte such as Nafion (registered trademark) and the above-described electrode catalyst. is there.
At least one of the catalyst layers 14a and 14b is an electrode catalyst including the above-described non-noble metal-based electrode catalyst, and both are preferably the non-noble metal-based electrode catalyst. The non-noble metal electrode catalyst may be used together with a noble metal electrode catalyst capable of activating a redox reaction with hydrogen or oxygen. The noble metal catalyst is preferably platinum fine particles, and the catalyst layers 14a and 14b may be formed by supporting fine particles of platinum on particulate or fibrous carbon such as activated carbon or graphite.

  The gas diffusion layers 16a and 16b are provided so as to sandwich both sides of the membrane-electrode assembly 20, and promote the diffusion of the raw material gas into the catalyst layers 14a and 14b. The gas diffusion layers 16a and 16b are preferably made of a porous material having electron conductivity. For example, a porous carbon non-woven fabric or carbon paper is preferable because the raw material gas can be efficiently transported to the catalyst layers 14a and 14b.

These hydrocarbon-based electrolyte membrane 12, catalyst layers 14a and 14b, and gas diffusion layers 16a and 16b constitute a membrane-electrode-gas diffusion layer assembly (MEGA). Such MEGA can be manufactured by the method shown below, for example.
First, a solution containing a polymer electrolyte and a catalyst are mixed to form a slurry of a catalyst composition.
The catalyst layer is formed on the gas diffusion layer by applying this onto a carbon nonwoven fabric or carbon paper for forming the gas diffusion layers 16a and 16b by spraying or screen printing, and evaporating the solvent. A laminated body is obtained. And while arrange | positioning so that each catalyst layer may oppose a pair of laminated body obtained, the hydrocarbon type electrolyte membrane 12 is arrange | positioned between them, and these are crimped | bonded. Thus, MEGA having the above-described structure is obtained. In addition, the formation of the catalyst layer on the gas diffusion layer is, for example, after forming the catalyst layer by applying and drying the catalyst composition on a predetermined substrate (polyimide, poly (tetrafluoroethylene), etc.) This can also be performed by transferring to a gas diffusion layer by hot pressing.

  Separator 18a, 18b is formed with the material which has electronic conductivity, As this material, carbon, resin mold carbon, titanium, stainless steel etc. are mentioned, for example. The separators 18a and 18b are preferably provided with grooves (not shown) serving as a flow path for fuel gas or the like on the catalyst layers 14a and 14b side.

  The fuel cell 10 can be obtained by sandwiching MEGA as described above between a pair of separators 18a and 18b and joining them together.

  The fuel cell of the present invention is not necessarily limited to the above-described configuration, and may have a different configuration as long as it does not depart from the spirit of the fuel cell. The fuel cell 10 may be one having the above-described structure sealed with a gas seal body or the like.

  Furthermore, the fuel cell 10 shown in FIG. 1 is the minimum unit of the polymer electrolyte fuel cell, and since the output of one cell is limited, a plurality of cells are arranged so that the required output can be obtained. It is preferable that they are connected in series and put to practical use as a fuel cell stack.

  The fuel cell of the present invention can operate as a solid polymer fuel cell when the fuel is hydrogen, and as a direct methanol fuel cell when the fuel is an aqueous methanol solution.

  The fuel cell provided with the membrane-electrode assembly of the present invention can be used as, for example, a small power source for mobile devices such as an automobile power source, a household power source, a mobile phone, and a portable personal computer.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not restrict | limited to an Example.

Example 1
[Production of non-noble metal-based electrode catalyst (A)]
A non-noble metal-based electrode catalyst (A) was produced according to the following procedure.
(Preparation of metal complex (A))
A metal complex (A) represented by the following reaction formula was prepared by the following method.

Under a nitrogen atmosphere, 10 ml ethanol solution containing 0.476 g cobalt chloride hexahydrate and 0.412 g 4-tert-butyl-2,6-diformylphenol was placed in a 50 ml eggplant flask and stirred at room temperature. . A solution prepared by dissolving 0.216 g of o-phenylenediamine in 5 ml of ethanol was gradually added to this solution. The mixture was refluxed for 2 hours to produce a brown precipitate. The precipitate was collected by filtration and dried to obtain a metal complex (A) (yield 0.465 g: yield 63%). In the above reaction formula, “Cl ₂ ” means that 2 equivalents of chlorine ions are used as counter ions, and “2H ₂ O” means that 2 equivalents of water molecules are used as other ligands. Indicates.
Elemental analysis value (%): C ₃₆ H ₃₈ Cl ₂ Co ₂ N ₄ O ₄
(Calculated value) C, 55.47; H, 4.91; N, 7.19.
(Measured value) C, 56.34; H, 4.83; N, 7.23.

(Preparation of non-noble metal electrode catalyst (A))
A metal complex (A) and a carbon carrier (Ketjen Black EC300J, trade name, manufactured by Lion Corporation) were mixed at a mass ratio of 1: 1, stirred in ethanol at room temperature for 15 minutes, and then 1.5 Torr (at room temperature). 199.983 Pa) under reduced pressure for 12 hours. The mixture was heat-treated at 600 ° C. for 2 hours under a nitrogen flow of 200 ml / min using a tubular furnace having quartz as a furnace core tube to obtain a non-noble metal-based electrode catalyst (A).

[Manufacture of hydrocarbon electrolyte membrane]
(Preparation of polymer electrolyte)
In accordance with the method described in Example 1 of International Publication WO2006 / 095919, a polymer electrolyte having the following chemical formula was obtained (number average molecular weight in terms of polystyrene: 120,000, weight average molecular weight in terms of polystyrene: 230,000). ). The obtained polymer electrolyte had an ion exchange capacity of 2.2 meq / g. In the following formula, “block” means that the compound of the following formula is a block copolymer composed of one or more of two types of blocks.

(Preparation of additives)
Diphenyl sulfone is used as a solvent, and 4,4′-dihydroxydiphenyl sulfone, 4,4′-dihydroxybiphenyl and 4,4′-dichlorodiphenyl sulfone are reacted at a molar ratio of 4: 6: 10 in the presence of potassium carbonate. Thus, a random copolymer was prepared. Next, the copolymer is subjected to bromination and phosphonate esterification treatment according to the method described in JP-A No. 2003-282096, and then further hydrolyzed to give a unit derived from a biphenol structure. Additive 1 having a structure containing about 0.2 bromo groups and about 1.7 phosphonic acid groups (groups represented by —P (O) (OH) ₂ ) per one was obtained.

(Manufacture of hydrocarbon electrolyte membrane)
A polymer electrolyte solution obtained by mixing the additive 1 with a mass ratio of 9: 1 was dissolved in dimethyl sulfoxide (DMSO) to a concentration of about 15% by mass to obtain a polymer electrolyte solution. Prepared. Next, this polymer electrolyte solution was dropped on a glass plate. Then, the polymer electrolyte solution was uniformly spread on the glass plate using a wire coater. At this time, the coating thickness was controlled by changing the clearance of the wire coater. After application, the polymer electrolyte solution was dried at 80 ° C. under normal pressure. Then, the obtained membrane was immersed in 1N hydrochloric acid, washed with ion-exchanged water, and dried at room temperature to obtain a hydrocarbon electrolyte membrane having a thickness of 30 μm.

[Preparation of catalyst ink for cathode]
0.23 g of the non-noble metal electrode catalyst (A) obtained above was added to 1.43 mL of a commercially available 5% by mass Nafion solution (solvent: lower alcohol containing 15 to 20% by mass of water), and ethanol was further added. 11.2 mL and 2.1 mL of water were added. The obtained mixture was subjected to ultrasonic treatment for 1 hour, and then stirred for 5 hours with a stirrer to obtain a cathode catalyst ink.

[Preparation of anode catalyst ink]
Commercially available 5% Nafion solution (solvent: lower alcohol containing 15-20% by mass of water) 6 mL of platinum-supported carbon (SA50BK, trade name, manufactured by N.E. Chemcat) on which 50% by mass of platinum is supported 0.83 g was added, and 13.2 mL of ethanol was further added. The obtained mixture was subjected to ultrasonic treatment for 1 hour and then stirred with a stirrer for 5 hours to obtain an anode catalyst ink.

[Production of MEA]
Next, in accordance with the method described in Japanese Patent Application Laid-Open No. 2004-089976, the catalyst ink was sprayed onto the electrolyte membrane.
First, the anode catalyst ink was applied to a 5.2 cm square region in the center of the electrolyte membrane cut into a 7 cm square by a spray method. At this time, the distance from the discharge port to the film was set to 6 cm, and the stage temperature was set to 75 ° C. Similarly, after eight times of overcoating, the substrate was left on the stage for 15 minutes to remove the solvent, and an anode catalyst layer on which 0.60 mg / cm ² of platinum catalyst was disposed was formed on the electrolyte membrane. I let you. Similarly, a cathode catalyst ink is spray-coated on the opposite surface of the electrolyte membrane, and a cathode catalyst layer on which 0.60 mg / cm ² of the non-noble metal-based electrode catalyst (A) is disposed is formed on the electrolyte membrane. To form a membrane-electrode assembly (MEA). Each value of the catalyst amount is a value not including a carbon support.

[Evaluation of power generation performance of fuel cells]
A fuel cell was manufactured using a commercially available JARI standard cell. That is, a carbon cloth cut into a 5.2 cm square and a carbon separator cut into a gas passage groove are arranged on both outer sides of the membrane-electrode assembly obtained above, and a current collector is further provided on the outer side thereof. The body and the end plate were arranged in order, and these were tightened with bolts to assemble and produce a fuel cell having an effective membrane area of 25 cm ² .

  While maintaining the obtained fuel cell at 30 ° C., humidified hydrogen was supplied to the anode and humidified air was supplied to the cathode. At this time, the back pressure at the gas outlet of the cell was set to 0.1 MPaG. Each source gas was humidified by passing the gas through a bubbler. The water temperature of the hydrogen bubbler was 30 ° C., and the water temperature of the air bubbler was 30 ° C. Here, the hydrogen gas flow rate was 529 mL / min, and the air gas flow rate was 1665 mL / min. The voltage when the current was swept was recorded, and the power generation performance of the fuel cell was evaluated.

FIG. 2 is a current-potential curve of the fuel cell produced as described above. The vertical axis represents the cell voltage (V), and the horizontal axis represents the current density (Acm ⁻² ).

Example 2
[Production of non-noble metal electrode catalyst (B)]
A non-noble metal-based electrocatalyst (B) was produced according to the following procedure.
(Preparation of metal complex (B))
A metal complex (B) represented by the following reaction formula was prepared by the following method. The ligand used as a raw material is “Tetrahedron”, Vol. 55, p. 8377 (1999). In the formulae, Me represents a methyl group, Et represents an ethyl group, and Ac represents an acetyl group.

First, in a nitrogen atmosphere, a 200 ml solution of 2-methoxyethanol containing 1.388 g of a ligand and 1.245 g of cobalt acetate tetrahydrate was placed in a 500 ml eggplant flask and heated to 80 ° C. for 2 hours. Upon stirring, a brown solid was formed. This solid was collected by filtration, further washed with 20 ml of 2-methoxyethanol (MeOEtOH) and dried to obtain a metal complex (B) (yield 1.532 g: yield 74%). “(OAc) ₂ ” on the right side of the above reaction formula indicates that 2 equivalents of acetate ion is present as a counter ion, and “MeOEtOH” indicates that 2-methoxyethanol molecule is present as a ligand. Show.
Elemental analysis value (%): C ₄₉ H ₅₀ Co ₂ N ₄ O ₈
(Calculated values) C: 62.56, H: 5.36, N: 5.96, Co: 12.53.
(Measured value) C: 62.12, H: 5.07, N: 6.03, Co: 12.74.

(Preparation of non-noble metal-based electrocatalyst (B))
A metal complex (B) and a carbon support (Ketjen Black EC600JD, trade name, manufactured by Lion Corporation) were mixed at a mass ratio of 1: 4, stirred in ethanol at room temperature for 15 minutes, and then 1.5 Torr (at room temperature). 199.983 Pa) under reduced pressure for 12 hours. The mixture was heat-treated at 800 ° C. for 2 hours under a nitrogen flow of 200 ml / min using a tubular furnace having quartz as a furnace core tube to obtain a non-noble metal electrode catalyst (B).

[Manufacture of hydrocarbon electrolyte membrane]
(Preparation of polymer electrolyte)
In accordance with the method described in Example 1 of International Publication WO2006 / 095919, a polymer electrolyte having the following chemical formula was obtained (number average molecular weight in terms of polystyrene: 120,000, weight average molecular weight in terms of polystyrene: 230,000). ). The obtained polymer electrolyte had an ion exchange capacity of 2.5 meq / g. In the following formula, “block” means that the compound of the following formula is a block copolymer composed of one or more of two types of blocks.

(Manufacture of hydrocarbon electrolyte membrane)
The polymer electrolyte obtained above and additive 1 were dissolved in dimethyl sulfoxide (DMSO) to a concentration of about 15% by mass to prepare a polymer electrolyte solution. Next, this polymer electrolyte solution was dropped on a glass plate. Then, the polymer electrolyte solution was uniformly spread on the glass plate using a wire coater. At this time, the coating thickness was controlled by changing the clearance of the wire coater. After application, the polymer electrolyte solution was dried at 80 ° C. under normal pressure. Then, the obtained membrane was immersed in 1N hydrochloric acid, washed with ion-exchanged water, and further dried at room temperature to obtain a hydrocarbon electrolyte membrane having a thickness of 20 μm.

[Preparation of catalyst ink for cathode]
0.75 g of the non-noble metal electrode catalyst (B) obtained above was added to 7.56 g of a commercially available 5% by mass Nafion solution (solvent: mixture of water and lower alcohol), and further 35.5 g of ethanol and water were added. 5.25 g was added. The obtained mixture was subjected to ultrasonic treatment for 1 hour and then stirred for 5 hours with a stirrer to obtain a non-noble metal-based electrode catalyst ink (B).

[Preparation of anode catalyst ink]
0.83 g of platinum-supported carbon (SA50BK, trade name, manufactured by N.E. Chemcat) in which 50% by mass of platinum is supported in 6 mL of a commercially available 5% by mass Nafion solution (solvent: mixture of water and lower alcohol), Furthermore, 13.2 mL of ethanol was added. The obtained mixture was subjected to ultrasonic treatment for 1 hour and then stirred with a stirrer for 5 hours to obtain an anode catalyst ink.

[Production of MEA]
Next, in accordance with the method described in Japanese Patent Application Laid-Open No. 2004-089976, the catalyst ink was sprayed onto the electrolyte membrane.
First, the anode catalyst ink was applied to a 5.2 cm square region in the center of the electrolyte membrane cut into a 7 cm square by a spray method. At this time, the distance from the discharge port to the film was set to 6 cm, and the stage temperature was set to 75 ° C. Similarly, after eight times of overcoating, the substrate was left on the stage for 15 minutes, the solvent was removed, and an anode catalyst layer on which 0.6 mg / cm ² of platinum-supported carbon was arranged was formed on the electrolyte membrane. Formed. Similarly, a cathode catalyst ink is spray-coated on the opposite surface of the electrolyte membrane, and a cathode catalyst layer on which 0.76 mg / cm ² of the non-noble metal-based electrode catalyst (B) is disposed is formed on the electrolyte membrane. To form a membrane-electrode assembly (MEA). Each value of the catalyst amount is a value not including a carbon support.

[Evaluation of power generation performance of fuel cells]
A fuel cell was manufactured using a commercially available JARI standard cell. That is, a carbon cloth cut into a 5.2 cm square and a carbon separator cut into a gas passage groove are arranged on both outer sides of the membrane-electrode assembly obtained above, and a current collector is further provided on the outer side thereof. The body and the end plate were arranged in order, and these were tightened with bolts to assemble and produce a fuel cell having an effective membrane area of 25 cm ² .

  While maintaining the obtained fuel cell at 80 ° C., humidified hydrogen was supplied to the anode and humidified air was supplied to the cathode. At this time, the back pressure at the gas outlet of the cell was set to 0.1 MPaG. Each source gas was humidified by passing the gas through a bubbler. The water temperature of the hydrogen bubbler was 70 ° C., and the water temperature of the air bubbler was 70 ° C. The hydrogen gas flow rate was 70 mL / min, and the air gas flow rate was 174 mL / min.

  FIG. 3 is a plot of current density versus elapsed time when the fuel cell produced above was operated at a constant voltage of 0.4V. The vertical axis represents cell voltage (V), and the horizontal axis represents elapsed time (h: time).

Next, using the produced fuel cell, the hydrogen gas flow rate was set to 529 mL / min, the air gas flow rate was set to 1665 mL / min, the voltage when the current was swept was recorded, and the power generation of the fuel cell Performance was evaluated.
FIG. 4 is a current-potential curve of the fuel cell produced as described above. The vertical axis represents the cell voltage (V), and the horizontal axis represents the current density (Acm ⁻² ).

Example 3
Using the fuel battery cell produced in Example 2, after connecting the anode side to the non-noble metal electrode catalyst (B) and the cathode side to platinum-supporting carbon, the hydrogen gas flow rate was 529 mL / min, and the air gas flow rate Was set to 1665 mL / min, the voltage when the current was swept was recorded, and the power generation performance of the fuel cell was evaluated.

FIG. 5 is a current-potential curve of a fuel cell using a non-noble metal electrode catalyst (B) as an anode side (hydrogen electrode side) catalyst. The vertical axis represents the cell voltage (V), and the horizontal axis represents the current density (Acm ⁻² ).

Example 4
[Production of non-noble metal electrode catalyst (C)]
A non-noble metal-based electrode catalyst (C) was produced according to the following procedure.
(Preparation of metal complex (C))
Metal complex (C) was synthesized via compound (A), compound (B) and compound (C) according to the following reaction formula.
[Synthesis of Compound (A)]

Under an argon atmosphere, 3.945 g of 2,9-di (3′-bromo-5′-tert-butyl-2′-methoxyphenyl) -1,10-phenanthroline, 3.165 g of 1-N-Boc- Pyrrole-2-boronic acid, 0.138 g of tris (benzylideneacetone) dipalladium, 0.247 g of 2-dicyclohexylphosphino-2 ′, 6′-dimethoxybiphenyl, 5.527 g of potassium phosphate and 200 mL of dioxane It melt | dissolved in the mixed solvent of 20 mL water, and stirred at 60 degreeC for 6 hours. After completion of the reaction, the mixture was allowed to cool, distilled water and chloroform were added, and the organic layer was extracted. The resulting organic layer was concentrated to give a black residue. This was refine | purified using the silica gel column, and the compound (A) was obtained.
¹ H-NMR (300 MHz, CDCl ₃ ) δ 1.34 (s, 18 H), 1.37 (s
18H), 3.30 (s, 6H), 6.21 (m, 2H), 6.27 (m, 2H), 7.37 (m, 2H), 7.41 (s, 2H), 7 .82 (s, 2H), 8.00 (s, 2H), 8.19 (d, J = 8.6 Hz, 2H), 8.27 (d, J = 8.6 Hz, 2H).
[Synthesis of Compound (B)]

Under a nitrogen atmosphere, 0.904 g of compound (A) is dissolved in 10 mL of anhydrous dichloromethane. While the dichloromethane solution was cooled to −78 ° C., 8.8 mL of boron tribromide (1.0 M dichloromethane solution) was slowly added dropwise. After dropping, the mixture was allowed to stir for 10 minutes and then allowed to stand while stirring to room temperature. After 3 hours, the reaction solution was cooled to 0 ° C., saturated aqueous NaHCO ₃ solution was added, chloroform was added for extraction, and the organic layer was concentrated. The resulting brown residue was purified with a silica gel column to obtain compound (B).
¹ H-NMR (300 MHz, CDCl ₃ ) δ 1.40 (s, 18H), 6.25 (m, 2H), 6.44 (m, 2H), 6.74 (m, 2H), 7.84 ( s, 2H), 7.89 (s, 2H), 7.92 (s, 2H), 8.35 (d, J = 8.4 Hz, 2H), 8.46 (d, J = 8.4 Hz, 2H), 10.61 (s, 2H), 15.88 (s, 2H).
[Synthesis of Compound (C)]

0.061 g of compound (B) and 0.012 g of benzaldehyde were dissolved in 5 mL of propionic acid and heated at 140 ° C. for 7 hours. Thereafter, propionic acid was distilled off, and the resulting black residue was purified with a silica gel column to obtain compound (C). By repeating the above operation, 0.2 g of Compound (C) was obtained.
¹ H-NMR (300 MHz, CDCl ₃ ) δ 1.49 (s, 18H), 6.69 (d, J = 4.8 Hz, 2H), 7.01 (d, J = 4.8 Hz, 2H), 7 .57 (m, 5H), 7.90 (s, 4H), 8.02 (s, 2H), 8.31 (d, J = 8.1 Hz, 2H), 8.47 (d, J = 8 .1Hz, 2H).
[Synthesis of Metal Complex (C)]

Under a nitrogen atmosphere, a mixed solution of 15 mL of methanol and 25 mL of chloroform containing 0.20 g of the compound (C) and 0.17 g of cobalt acetate tetrahydrate was refluxed for 5 hours with stirring. The resulting solution was concentrated to dryness to give a blue solid. This was washed with water to obtain a metal complex (C).
ESI-MS [M + ·]: 866.0
(Preparation of non-noble metal-based electrocatalyst (C))
A metal complex (C) and a carbon support (Ketjen Black EC300J, trade name, manufactured by Lion Corporation) were mixed at a mass ratio of 1: 4, stirred in ethanol at room temperature for 15 minutes, and then 1.5 Torr (at room temperature). 199.983 Pa) under reduced pressure for 12 hours. The mixture was heat-treated at 600 ° C. for 2 hours under a nitrogen flow of 200 ml / min using a tubular furnace having quartz as a furnace core tube to obtain a non-noble metal-based electrode catalyst (C).
[Preparation of non-noble metal electrode catalyst ink (C)]
0.46 g of the non-noble metal-based electrocatalyst (C) obtained above was added to 4.61 g of a commercially available 5% by mass Nafion solution (solvent: mixture of water and lower alcohol), and further 3.29 g of water and ethanol 21 .65 g was added. The obtained mixture was subjected to ultrasonic treatment for 1 hour and then stirred with a stirrer for 5 hours to obtain a non-noble metal-based electrode catalyst ink (C).
[Production of MEA]
The prepared non-noble metal electrode catalyst ink (C) is applied to one side of the same electrolyte membrane as the electrolyte membrane used in Example 2, and the non-noble metal electrode catalyst ink (B) prepared in Example 2 is applied to the opposite surface. The membrane-electrode assembly (MEA) was obtained by spray-coating according to the method described above. Fabricated film - the one surface of the electrode assembly, the non-noble metal-based electrode catalyst of 0.60mg / cm ² (B) is a non-noble metal-based electrode catalyst on one side opposite to 0.54mg / cm ² (C) Is arranged. Each value of the catalyst amount is a value not including a carbon support.
[Evaluation of power generation performance of fuel cells]
Using the membrane-electrode assembly obtained above, a fuel cell was produced according to the method described in Example 3. Connect the non-noble metal electrode catalyst (B) to the hydrogen side and the non-noble metal electrode catalyst (C) to the air side, and set the hydrogen gas flow rate to 529 mL / min and the air gas flow rate to 1665 mL / min. And when the open circuit voltage of the fuel cell was measured, it was 0.76V.

  As is clear from the results of Examples 1 to 4, the fuel cell using the membrane-electrode assembly having the non-noble metal-based electrode catalyst and the hydrocarbon-based electrolyte membrane does not significantly reduce the power generation performance, and the noble metal Therefore, the manufacturing cost of the fuel cell can be greatly reduced. Moreover, from the results of Example 2, it was shown that when a membrane-electrode assembly having a non-noble metal-based electrode catalyst and a hydrocarbon-based electrolyte membrane was used, power was stably generated.

FIG. 1 is a longitudinal sectional view of a cell of a fuel cell according to a preferred embodiment of the present invention. FIG. 2 is a current-potential curve of a fuel cell using the membrane-electrode assembly of Example 1. FIG. 3 is a plot of current density versus elapsed time of a fuel cell using the membrane-electrode assembly of Example 2. 4 is a current-potential curve of a fuel cell using the membrane-electrode assembly of Example 2. FIG. 4 is a current-potential curve of a fuel cell using the membrane-electrode assembly of Example 3. FIG.

Explanation of symbols

10 Fuel cell (fuel cell)
12 Hydrocarbon electrolyte membrane (proton conducting membrane)
14a, 14b Catalyst layers 16a, 16b Gas diffusion layers 18a, 18b Separator 20 Membrane-electrode assembly

Claims (5)

  A membrane-electrode assembly comprising a catalyst layer containing an electrode catalyst on both sides of an electrolyte membrane, wherein at least one of the catalyst layers contains a non-noble metal-based electrode catalyst, and the electrolyte membrane is a hydrocarbon-based electrolyte membrane A membrane-electrode assembly characterized by being.   The membrane-electrode assembly according to claim 1, wherein the non-noble metal-based electrode catalyst is an electrode catalyst using a non-noble metal complex.   The membrane-electrode assembly according to claim 1 or 2, wherein the hydrocarbon-based electrolyte membrane includes an aromatic hydrocarbon-based polymer electrolyte.   The membrane-electrode assembly according to any one of claims 1 to 3, wherein the hydrocarbon-based electrolyte membrane is a hydrocarbon-based electrolyte membrane having proton conductivity.   A fuel cell comprising the membrane-electrode assembly according to any one of claims 1 to 4.

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