Cathode catalyst layer, membrane catalyst assembly, cathode gas diffusion electrode, membrane electrode assembly and polymer electrolyte fuel cell using the same

摘要

PPROBLEM TO BE SOLVED: To provide a catalyst layer capable of realizing a polymer electrolyte fuel cell with high initial voltage, capable of maintaining battery voltage for a long period, and in particular, has a superior durability against a sudden change in potential at the time of operation or stoppage. PSOLUTION: In a membrane electrode assembly 20 consisting of a polymer electrolyte membrane 11 having a hydrogen ion conductivity, an anode 16 and a cathode 15 pinching the polymer electrolyte membrane 11, the cathode catalyst layer 12 is constructed of at least two layers, and the particle size of the metal catalyst contained in a first catalyst layer on the side contacting the polymer electrolyte membrane 11 is made large than that of the metal catalyst layer contained in the second catalyst layer on the side which does not contact the polymer electrolyte membrane 11, and an alloy catalyst is used for the metal catalyst of the first catalyst layer. PCOPYRIGHT: (C)2008,JPO&INPIT