Abstract: A fuel cell system includes: a fuel cell including a fuel gas passage through which a fuel gas flows and an oxidant gas passage through which an oxidant gas flows, an inlet of the fuel gas passage being located closer to an outlet of the oxidant gas passage than to an inlet of the oxidant gas passage, an outlet of the fuel gas passage being located closer to the inlet of the oxidant gas passage than to the outlet of the oxidant gas passage; an oxidant gas supply unit supplying the oxidant gas to the fuel cell; and a supply amount controller configured to control the oxidant gas supply unit, the supply amount controller is configured to control the oxidant gas supply unit so that a stoichiometric ratio of the oxidant gas in a high-temperature high output power state is greater than that in a high-temperature low output power state.

Abstract: A fuel cell system includes: a fuel cell including a fuel gas passage through which a fuel gas flows and an oxidant gas passage through which an oxidant gas flows, an inlet of the fuel gas passage being located closer to an outlet of the oxidant gas passage than to an inlet of the oxidant gas passage, an outlet of the fuel gas passage being located closer to the inlet of the oxidant gas passage than to the outlet of the oxidant gas passage; an oxidant gas supply unit supplying the oxidant gas to the fuel cell; and a supply amount controller configured to control the oxidant gas supply unit, the supply amount controller is configured to control the oxidant gas supply unit so that a stoichiometric ratio of the oxidant gas in a high-temperature high output power state is greater than that in a high-temperature low output power state.

Abstract: The present invention is to provide such a carbon-supported catalyst that an activity expected from a catalytic activity by rotating disk electrode (RDE) evaluation is maintained even after the formation of a membrane electrode assembly (MEA). Disclosed is a carbon-supported catalyst wherein the carbon-supported catalyst includes fine catalyst particles that have a palladium-containing particle and a platinum-containing outermost layer covering at least part of the palladium-containing particle, and a carbon support supporting the fine catalyst particles, and wherein, in a cyclic voltammogram that is obtained by measuring, in an acid solution, the carbon-supported catalyst applied to a measurement electrode made of an electroconductive material, the proportion of the area of a hydrogen adsorption region that appears in a reduction current region to the total area of the hydrogen adsorption region and a hydrogen occlusion region that appears in the reduction current region, is 29% to 36%.

Abstract: The present invention is to provide such a carbon-supported catalyst that an activity expected from a catalytic activity by rotating disk electrode (RDE) evaluation is maintained even after the formation of a membrane electrode assembly (MEA). Disclosed is a carbon-supported catalyst wherein the carbon-supported catalyst includes fine catalyst particles that have a palladium-containing particle and a platinum-containing outermost layer covering at least part of the palladium-containing particle, and a carbon support supporting the fine catalyst particles, and wherein, in a cyclic voltammogram that is obtained by measuring, in an acid solution, the carbon-supported catalyst applied to a measurement electrode made of an electroconductive material, the proportion of the area of a hydrogen adsorption region that appears in a reduction current region to the total area of the hydrogen adsorption region and a hydrogen occlusion region that appears in the reduction current region, is 29% to 36%.

Abstract: To improve oxidation resistance of an electrolyte membrane and durability thereof by a low-cost method, thereby improving durability of a polymer electrolyte fuel cell. According to the present invention, in the polymer electrolyte fuel cell having a membrane-electrode assembly including a polymer electrolyte membrane and electrodes bonded to both sides of the polymer electrolyte membrane, phosphate containing at least one metallic element selected from a rare earth element, Ti, Fe, Al and Bi is fixed to at least one of the polymer electrolyte membrane and the electrodes.