ELECTRODE CATALYST BODY FOR FUEL CELL, AIR ELECTRODE FOR FUEL CELL USING IT, AND EVALUATING METHOD OF ITS CATALYSTIC ACTIVITY

摘要

PROBLEM TO BE SOLVED: To provide an electrode catalyst body with a large catalystic activity for a fuel cell, wherein a conductive carrier carries catalyst particles. SOLUTION: This powdered electrode catalyst body for the fuel cell comprises the catalyst particles containing platinum and the conductive carrier for carrying the particles and is formed so that the ratio of the average value D111 of a crystallite diameter perpendicular to the crystalline plane 111 of catalyst particles to the average value D100 of a crystallite diameter perpendicular to the crystalline plane 100 is D100 /D111 <1, and the average crystallite diameter of the catalyst particles is not more than 5 nm. Since a surface area acting as a catalyst is large, and the proportion of the catalyst particles exposing the crystalline planes on their surfaces is large, an electrode catalyst body having high oxygen reducing activity can be obtained.