CATALYST PARTICLES, CATALYST INK, ELECTRODE CATALYST LAYER FOR FUEL CELLS, MEMBRANE ELECTRODE ASSEMBLY, SOLID POLYMER FUEL CELL, METHOD FOR PRODUCING CATALYST PARTICLES, AND METHOD FOR PRODUCING CATALYST INK

摘要

Provided is a method for producing catalyst particles (P3), which are used in electrode catalyst layers (52A, 52F) for the purpose of increasing the output voltage of a polymer electrolyte fuel cell (50). Before dispersing the catalyst particles (P3), which are carbon particles (P1) supporting a catalyst material (P2), and a polymer electrolyte (PE) in a solvent (S) for a catalyst ink, the carbon particles (P1) are exposed to a humidified atmosphere (M). The moisture content of the catalyst particles (P3) is from 4.8 mass% to 20 mas%, inclusive.