Membrane/electrode assembly for polymer electrolyte fuel cell and process for producing membrane/electrode assembly for polymer electrolyte fuel cell

A membrane/electrode assembly for a polymer electrolyte fuel cell, comprising:

• an anode having an anode catalyst layer comprising an anode catalyst and an ion-exchange resin;
• a cathode having a cathode catalyst layer comprising a cathode catalyst and an ion-exchange resin;
• and
• a polymer electrolyte membrane disposed between the anode and the cathode,
• wherein the anode catalyst is one of platinum and a platinum alloy supported on a carbon support, the platinum or platinum alloy in the anode catalyst is in an amount of from 1 to 25 mass %, the anode catalyst layer has a thickness in a range of from 1 to 30 μm, the anode catalyst layer includes fine particles made of at least one member selected from the group consisting of iridium oxide, iridium, ruthenium oxide and ruthenium, the fine particles have a specific surface area in a range of from 2 to 50 m2/g and a content as calculated as metal in a range of from 0.01 to 0.09 mg/cm2, and the ratio of a content of the carbon support in the anode catalyst to the content of the fine particles as calculated as metal is in a range of from 30/1 to 2/1.