Abstract: To provide a membrane/electrode assembly for polymer electrolyte fuel cells capable of obtaining a high output voltage even in a high current density region, by providing electrodes having good gas diffusion properties, conductivity, water repellency and durability. A membrane/electrode assembly for polymer electrolyte fuel cells, comprising; an anode and a cathode each having a catalyst layer containing a catalyst and having a gas diffusion layer; and a polymer electrolyte membrane disposed between the catalyst layer of the anode and the catalyst layer of the cathode, characterized in that at least one of the above anode and cathode, has a carbon layer containing a fluorinated ion exchange resin and carbon nanofibers having a fiber diameter of from 1 to 1,000 nm and a fiber length of at most 1,000 ?m, disposed between the catalyst layer and the gas diffusion layer.

Abstract: To provide a membrane/electrode assembly less susceptible to flooding on shortcircuiting caused by piercing of carbon fibers of a gas diffusion layer to a polymer electrolyte membrane. A membrane/electrode assembly 10, comprising a cathode 20 having a catalyst layer 22 and a gas diffusion layer 26, an anode 30 having a catalyst layer 32 and a gas diffusion layer 36, and a polymer electrolyte membrane 40 interposed between the catalyst layer 22 of the cathode 20 and the catalyst layer 32 of the anode 30, wherein each of the cathode 20 and the anode 30 further has a protective layer 24 or 34 comprising carbon fibers having an average fiber diameter of from 1 to 30 ?m and a fluorinated ion exchange resin, between the catalyst layer and the gas diffusion layer, and the mass ratio (F/C) of the fluorinated ion exchange resin (F) to the carbon fibers (C) contained in the protective layer is from 0.05 to 0.30.

Abstract: Provision of a process for producing a membrane/electrode assembly for a polymer electrolyte fuel cell which can produce a high output voltage in a wide current density range.

Abstract: To provide a membrane/electrode assembly in which flooding in a catalyst layer is less likely to occur; a coating fluid for forming a catalyst layer capable of forming a catalyst layer in which flooding is less likely to occur; and a process for producing a membrane/electrode assembly in which flooding in a catalyst layer is less likely to occur.

Abstract: To provide a process for forming a catalyst layer whereby defects such as cracks are scarcely formed in the catalyst layer, and the bond strength is high at the interface between the catalyst layer and a reinforcing layer and at the interface between the catalyst layer and a polymer electrolyte membrane; and a process for producing a membrane/electrode assembly for a polymer electrolyte fuel cell, which is capable of exhibiting high power generation performance even under a low humidity condition and has sufficient mechanical strength and dimensional stability and which has excellent durability even in an environment where humidification and drying, etc. are repeated. In the production of a membrane/electrode assembly 10, a first catalyst layer 22 (a second catalyst layer 34) is formed by a process comprising steps (a) and (b). (a) A step of applying a coating fluid comprising a catalyst and an ion-exchange resin, on a substrate to form a coating fluid layer.

Abstract: Provided are a process for producing a membrane/electrode assembly for a polymer electrolyte fuel cell and a process for producing a polymer electrolyte fuel cell, capable of achieving a high output voltage in a wide current density range. At least one of an anode and a cathode in a membrane/electrode assembly for a polymer electrolyte fuel cell is formed through a catalyst layer forming step of applying a first coating fluid containing a catalyst and an ion exchange resin, onto a substrate to form a catalyst layer; a gas diffusion layer forming step of applying a second coating fluid containing carbon fibers and an ion exchange resin, onto the catalyst layer to form a gas diffusion layer to serve as an outermost layer of the membrane/electrode assembly for the polymer electrolyte fuel cell; and a peeling step of peeling the substrate off from the catalyst layer.

Abstract: To provide a membrane/electrode assembly excellent in durability and capable of providing a high output voltage, and a process for its production. A membrane/electrode assembly 10 for a polymer electrolyte fuel cell, comprising a polymer electrolyte membrane 12; a first frame 14 disposed at the periphery of a first surface of the polymer electrolyte membrane 12; a second frame 16 disposed at the periphery of a second surface of the polymer electrolyte membrane 12; a first electrode 22 having a first catalyst layer 18 and a first gas diffusion layer 20; and a second electrode 28 having a second catalyst layer 24 and a second gas diffusion layer 26; wherein the inner edge portion of the is first frame 14 is located between the first catalyst layer 18 and the first gas diffusion layer 20; and the inner edge portion of the second frame 16 is located between the polymer electrolyte membrane 12 and the second catalyst layer 24.

Abstract: To provide a membrane/electrode assembly for polymer electrolyte fuel cells capable of obtaining a high output voltage even in a high current density region, by providing electrodes having good gas diffusion properties, conductivity, water repellency and durability. A membrane/electrode assembly for polymer electrolyte fuel cells, comprising; an anode and a cathode each having a catalyst layer containing a catalyst and having a gas diffusion layer; and a polymer electrolyte membrane disposed between the catalyst layer of the anode and the catalyst layer of the cathode, characterized in that at least one of the above anode and cathode, has a carbon layer containing a fluorinated ion exchange resin and carbon nanofibers having a fiber diameter of from 1 to 1,000 nm and a fiber length of at most 1,000 ?m, disposed between the catalyst layer and the gas diffusion layer.

Abstract: A solid polymer electrolyte material made of a copolymer comprising a repeating unit based on a fluoromonomer A which gives a polymer having an alicyclic structure in its main chain by radical polymerization, and a repeating unit based on a fluoromonomer B of the following formula (1): CF2?CF(Rf)jSO2X??(1) wherein j is 0 or 1, X is a fluorine atom, a chlorine atom or OM {wherein M is a hydrogen atom, an alkali metal atom or a group of NR1R2R3R4 (wherein each of R1, R2, R3 and R4 which may be the same or different, is a hydrogen atom or a monovalent organic group)}, and Rf is a C1-20 polyfluoroalkylene group having a straight chain or branched structure which may contain ether oxygen atoms.

Abstract: A process is provided whereby a membrane/electrode assembly for polymer electrolyte fuel cells whereby a high output voltage is obtainable within a wide range of current densities.

Abstract: A process comprising: providing a substrate with a catalyst layer thereon; depositing a first ionomer overcoat layer over the catalyst layer, the first ionomer overcoat layer comprising an ionomer and a first solvent; drying the first ionomer overcoat layer to provide a first electrode ionomer overcoat layer; depositing a second ionomer overcoat layer over the first electrode ionomer overcoat layer, and wherein the second ionomer overcoat layer comprises an ionomer and a second solvent.

Abstract: A solid polymer electrolyte material made of a copolymer comprising a repeating unit based on a fluoromonomer A which gives a polymer having an alicyclic structure in its main chain by radical polymerization, and a repeating unit based on a fluoromonomer B of the following formula (1): CF2?CF(Rf)jSO2X??(1) wherein j is 0 or 1, X is a fluorine atom, a chlorine atom or OM {wherein M is a hydrogen atom, an alkali metal atom or a group of NR1R2R3R4 (wherein each of R1, R2, R3 and R4 which may be the same or different, is a hydrogen atom or a monovalent organic group)}, and Rf is a C1-20 polyfluoroalkylene group having a straight chain or branched structure which may contain ether oxygen atoms.

Abstract: A process for producing a membrane-electrode assembly for a polymer electrolyte fuel cell comprising an anode and a cathode each having a catalyst layer, and an ion exchange membrane disposed between them, and the membrane-electrode assembly so produced, wherein at least one of the catalyst layers is produced by preparing a coating fluid containing an ion exchange polymer and a catalyst having catalytic metal particles dispersed on a carbon support, and a catalyst layer is formed by applying the coating fluid on a substrate, wherein the catalyst has a density of total functional groups of OH groups and CO groups at the surface is at most 1.6×10?3 (mmol/m2), as obtained from the BET specific surface area and the total molar amount of OH groups and CO groups at the surface obtained by a titration method.

Abstract: A process for producing a membrane-electrode assembly for a polymer electrolyte fuel cell comprising an anode and a cathode each having a catalyst layer, and an ion exchange membrane disposed between them, characterized in that a step of producing at least one of the catalyst layers of the anode and cathode, comprises a step of preparing a coating fluid containing an ion exchange polymer and a catalyst having catalytic metal particles dispersed on a carbon support, and a step of forming a catalyst layer by applying the coating fluid on a substrate, wherein the above coating fluid is prepared by using, as the above catalyst, a catalyst wherein the density of total functional groups of OH groups and CO groups at the surface is at most 1.6×10?3 (mmol/m2), as obtained from the BET specific surface area and the total molar amount of OH groups and CO groups at the surface obtained by a titration method.

Abstract: A solid polymer electrolyte material made of a copolymer comprising a repeating unit based on a fluoromonomer A which gives a polymer having an alicyclic structure in its main chain by radical polymerization, and a repeating unit based on a fluoromonomer B of the following formula (1):

Abstract: A polymer electrolyte fuel cell comprising an ion exchange membrane, and a cathode and an anode facing each other via the ion exchange membrane, wherein the cathode comprises an ion exchange resin and an electrode catalyst having platinum or a platinum alloy deposited on a carbon support which has an average lattice spacing of (002) d002 calculated by the X-ray diffraction data, of from 0.340 to 0.362 nm, a microcrystallite size Lc of from 0.6 to 4 nm and a specific surface area of from 260 to 800 m2/g.

Abstract: The present invention relates to a simple method for producing 3,3-dichloro-1,1,1,2,2-pentafluoropropane (R225ca) and 1,3-dichloro-1,1,2,2,3-pentafluoropropane (R225cb) in good yield and at high selectivity by reacting tetrafluoroethylene (C2F4) and dichlorofluoromethane (R21) in the presence of a certain specific catalyst. The specific catalyst in the present invention is (1) a catalyst comprising halogenated oxide containing at least one element of Group 4, Group 5 and Group 13 such as Ti, Zr, Hf, V, B and Ga, or (2) a catalyst comprising halogenated oxide containing at least one element selected from Group 4, Group 5 and Group 13 such as Ti, Zr, Hf, V, B, Al and Ga and at least one element selected from Group 2, Group 6, Group 12 and Group 14 such as Ba, W, Zn, Si, Bi and P.

Abstract: An alumina hydrate coating fluid having alumina hydrate particles dispersed in an aqueous medium, which contains, as binders, a polyvinyl alcohol and a polymerizable binder which is a compound having a hydrocarbon group with a hydroxy group or a compound having a polyoxyalkylene chain, said compound having a substituent with an unsaturated bond or a substituent with an epoxy group.

Abstract: An alumina sol having colloidal particles of alumina hydrate dispersed in an aqueous solvent, said sol containing a compound which has a sulfonic acid group in its molecule and which, when made into a 1 wt % aqueous solution, has a pH of at most 4.

Abstract: An alumina sol having colloidal particles of alumina hydrate dispersed in an aqueous solvent, said sol containing a compound which has a sulfonic acid group in its molecule and which, when made into a 1 wt % aqueous solution, has a pH of at most 4.