In this fuel cell electrode catalyst layer, a catalyst is supported on a carrier comprising inorganic oxide particles. The fuel cell electrode catalyst layer is provided with a porous structure. When a mercury penetration method is used to measure the pore size distribution of the porous structure, a peak is observed in the range spanning from 0.005 μm to 0.1 μm inclusive, and a peak is also observed in the range spanning from over 0.1 μm to not more than 1 μm. When P1 represents the peak intensity in the range spanning from 0.005 μm to 0.1 μm inclusive, and P2 represents the peak intensity in the range spanning from over 0.1 μm to not more than 1 μm, the value of P2/P1 is 0.2-10 inclusive. It is preferable that the inorganic oxide be tin oxide.

Provided is a catalyst for fuel cell which has a high catalytic activity and enables maintaining the high catalytic activity. Disclosed is an electrode catalyst for fuel cell comprising a catalyst carrier containing carbon as a main component and a catalytic metal supported on the catalyst carrier, wherein the catalyst has the R′ (D′/G intensity ratio) of 0.6 or less, which is the ratio of D′ band peak intensity (D′ intensity) measured in the vicinity of 1620 cm.sup.−1 relative to G band peak intensity (G intensity) measured in the vicinity of 1580 cm.sup.−1 by Raman spectroscopy, and the volume ratio of a water vapor adsorption amount relative to a nitrogen adsorption amount at a relative pressure of 0.5 in adsorption isotherm is 0.15 or more and 0.30 or less.

The present invention relates to an electrode catalyst for fuel cell containing a catalyst carrier having carbon as a main component and a catalytic metal carried on the catalyst carrier, wherein the electrode catalyst for fuel cell has a ratio R′ (D′/G intensity ratio) of a peak intensity of D′ band (D′ intensity) measured in the vicinity of 1620 cm.sup.−1 to a peak intensity of G band (G intensity) measured in the vicinity of 1580 cm.sup.−1 by Raman spectroscopy of more than 0.6 and 0.8 or less, and satisfies at least one of the (a) to (d). According to the present invention, an electrode catalyst for fuel cell excellent in gas transportability is provided.

A method for producing a membrane electrode assembly for a fuel cell comprising a proton exchange polymer membrane, catalyst layers, and first and second gas diffusion layers, the method comprising the following steps: a) forming a catalytic layer coating on a first surface of the membrane, the opposite surface being supported by a spacer; b) forming a catalytic layer coating on a first surface of the first gas diffusion layer; c) bringing the first surface of the first gas diffusion layer into contact with the surface opposite to the said first surface of the membrane, after removing the spacer, and bringing the first surface of the membrane into contact with a surface of the second gas diffusion layer.

An illustrative example method of making a fuel cell component includes mixing a catalyst material with a hydrophobic binder in a solvent to establish a liquid mixture having at least some coagulation of the catalyst material and the hydrophobic binder. The liquid mixture is applied to at least one side of a porous gas diffusion layer. At least some of the solvent of the applied liquid mixture is removed from the porous gas diffusion layer. The catalyst material remaining on the porous gas diffusion layer is dried under pressure.

The invention provides electro-catalyst compositions for an anode electrode of an acid mediated proton exchange membrane-based water electrolysis system. The compositions include a noble metal component selected from the group consisting of iridium oxide, ruthenium oxide, rhenium oxide and mixtures thereof, and a non-noble metal component selected from the group consisting of tantalum oxide, tin oxide, niobium oxide, titanium oxide, tungsten oxide, molybdenum oxide, yttrium oxide, scandium oxide, cooper oxide, zirconium oxide, nickel oxide and mixtures thereof. Further, the non-noble metal component can include a dopant. The dopant can be at least one element selected from Groups III, V, VI and VII of the Periodic Table. The compositions can be prepared using any solution based methods involving a surfactant approach or a sol gel approach. Further, the compositions are prepared using noble metal and non-noble metal precursors. Furthermore, a thin film containing the compositions can be deposited onto a substrate to form the anode electrode.

A catalyst layer for a fuel cell, wherein the catalyst layer comprises a catalyst-supporting carbon and an ionomer; wherein, in a particle size distribution obtained by the laser diffraction/scattering method, the catalyst-supporting carbon has at least two aggregate particle size peaks at less than 1 μm and at 1 μm or more; wherein, when a thickness of the catalyst layer is divided into three equal parts, the catalyst layer has a first region on a gas diffusion layer side, a second region in a middle part, and a third region on an electrolyte membrane side; and wherein a void ratio V.sub.G of the first region is 5% or more higher than a void ratio V.sub.M of the third region.

A composition for filling an ion exchange membrane, a method of preparing the ion exchange membrane, the filled ion exchange membrane, and a redox flow battery using the filled ion exchange membrane. The composition includes an ion conductive material and a water soluble support.

The present invention relates to a laminate comprising (i) an ion exchange membrane comprising an ion exchange polymer, and (ii) a monolayered release film removably adhered to at least one side of the ion exchange membrane, wherein the monolayered release film comprises at least 95% by weight of syndiotactic polystyrene (sPS). The invention also relates to a method for producing the laminate, use of the monolayered release film in producing an electrolyte membrane or a membrane electrode assembly, and a method for producing an electrolyte membrane or a membrane electrode assembly.

A catalyst layer for a fuel cell contains a support and a catalyst supported on the support. The support contains a titanium oxide having a crystal phase of Ti.sub.2O. The ratio of total abundance of trivalent Ti and divalent Ti (W2) to abundance of tetravalent Ti (W1), W2/W1, is 0.1 or more as determined on the surface of the catalyst layer by X-ray photoelectron spectroscopy. The catalyst is preferably made of at least one metal selected from platinum, iridium, and ruthenium, or an alloy thereof. Also, the catalyst layer for a fuel cell preferably further contains an ionomer, and the ratio of mass of the ionomer (I) to mass of the catalyst-supporting support (S), I/S, is preferably 0.06 or more and 0.23 or less.