A catalyst includes a mesoporous material and catalytic metal particles supported at least within the mesoporous material and containing platinum and a metal different from platinum. The mesoporous material has mesopores with a mode radius of 1 to 25 nm and a pore volume of 1.0 to 3.0 cm.sup.3/g before supporting of the catalytic metal particles, and has an average particle size of greater than or equal to 200 nm. A molar ratio of the metal different from platinum and contained in the catalytic metal particles relative to all metals contained in the catalytic metal particles is greater than or equal to 0.25, and among the catalytic metal particles, a volume ratio of catalytic metal particles having a particle size of greater than or equal to 20 nm is less than or equal to 10%.

A support powder can improve cell performance under high humidity environment. A support and metal catalyst, including: a support powder; and metal fine particles supported on the support powder; wherein: the support powder is an aggregate of support fine particles; the support fine particles are fine particles of oxide compound and has a chained portion structured by a plurality of crystallites being fusion bonded to form a chain; the crystallites have a size of 10 to 30 nm; the support powder has a void; the void includes a secondary pore having a pore diameter of more than 25 nm and 80 nm or less determined by BJH method; and a volume of the secondary pore per unit volume of the support fine particles structuring the support powder is 0.313 cm.sup.3/cm.sup.3 or more, is provided.

A membrane electrode assembly (MEA) includes a membrane, a cathode catalyst layer, a cathode co-catalyst layer including a hydrogen reservoir, an anode catalyst layer, and an anode co-catalyst layer including a hydrogen reservoir. The anode co-catalyst layer and the cathode co-catalyst layer cap a cathode potential at lower than 1.5V and an anode potential at lower than 1.0V. The anode co-catalyst layer and the cathode co-catalyst layer can include a platinum doped rare earth oxide, such as platinum doped cerium oxide.

Techniques for improving fuel cells are presented herein. An electrochemical fuel cell, in accordance with an aspect of the present disclosure comprises bipolar plate layers comprising an anode plate and a cathode plate; a fuel supply to the anode plate; an oxidant supply to the cathode plate; gas diffusion layers proximate to a respective bipolar plate layer; an electrolyte membrane layer; a graphite honeycomb structure positioned between a gas diffusion layer and the electrolyte membrane layer; and a de-alloyed platinum with immobilized enzymes coupled to the graphite honeycomb structure.

A supporting body includes a cluster of an alloy containing Pt and Co, and a support on which the cluster is supported. An amount of Pt supported is 1×10.sup.−14 ng/cm.sup.2 or more and 1×10.sup.5 ng/cm.sup.2 or less.

This catalyst for electrodes comprises: a porous carbon support which has nanopores having a pore diameter of from 1 nm to 20 nm; and a plurality of catalyst particles which are supported by the support. The catalyst particles contain Pt (zerovalent), and are supported by both inner portions and outer portions of the nanopores of the support. If an analysis of the particle size distribution of the catalyst particles is performed using three-dimensional reconstructed images obtained through a STEM-based electron tomography measurement, the proportion of the catalyst particles supported by the inner portions of the nanoparticles is 50% or more: at least one nanopore is formed in a cubic image having a side of from 20 nm to 50 nm, said cubic image being obtained from a three-dimensional reconstructed image of a catalyst aggregate; and this nanopore has the shape of a continuously extending interconnected pore.

An innovative fuel cell system with membrane electrode assemblies (MEAs) includes a polymer electrolyte membrane, a gas diffusion layer (GDL) made of porous metal foam, and a catalyst layer. A fuel cell has a metal foam layer that improves efficiency and lifetime of the conventional gas diffusion layer, which consists of both gas diffusion barrier (GDB) and microporous layer (MPL). This metal foam GDL enables consistent maintenance of the suitable structure and even distribution of pores during the operation. Due to the combination of mechanical and physical properties of metallic foam, the fuel cell is not deformed by external physical strain. Among many other processing methods of open-cell metal foams, ice-templating provides a cheap, easy processing route suitable for mass production. Furthermore, it provides well-aligned and long channel pores, which improve gas and water flow during the operation of the fuel cell.

An alloy composed of three or more types of elements, wherein all the standard deviation of distribution in the alloy of each element constituting the alloy are 15 atomic % or less provides a novel alloy composed of three or more types of elements and having a high solid solution uniformity.

A support powder can improve cell performance under high humidity environment. A support and metal catalyst, including: a support powder; and metal fine particles supported on the support powder; wherein: the support powder is an aggregate of support fine particles; the support fine particles are fine particles of oxide compound and has a chained portion structured by a plurality of crystallites being fusion bonded to form a chain; the crystallites have a size of 10 to 30 nm; the support powder has a void; the void includes a secondary pore having a pore diameter of more than 25 nm and 80 nm or less determined by BJH method; and a volume of the secondary pore per unit volume of the support fine particles structuring the support powder is 0.313 cm.sup.3/cm.sup.3 or more, is provided.

A catalyst support material for a proton exchange membrane fuel cell (PEMFC). The catalyst support material includes a metal material of an at least partially oxidized form of TiNb.sub.3O.sub.6 reactive with H.sub.3O.sup.+, HF and/or SO.sub.3.sup.− to form reaction products in which the metal material of the at least partially oxidized form of TiNb.sub.3O.sub.6 accounts for a stable molar percentage of the reaction products.