CATALYST FOR FUEL CELL, FUEL CELL ELECTRODE, MEMBRANE ELECTRODE COMPLEX AND FUEL CELL

PROBLEM TO BE SOLVED: To provide catalyst for a fuel cell containing high active performance for reducing poisons by intermediate products such as CO or/and CHO. SOLUTION: As a result of an examination in order to achieve above invention, the catalyst includes at least platinum. The catalyst is in a range from 65.1 to 67.3 degrees for a peak position of a maximum peak from 2θ=62 to 76 degrees in a diffraction pattern obtained by carrying out particle X-ray diffraction measurement, and/or in a range from 39.0 to 39.5 degrees for a peak position of a maximum peak from 2θ=36 to 44 degrees, and/or includes at least platinum and a second metal component. In the diffraction pattern obtained by a particle X-ray diffraction measurement, when a crystallite size is calculated by a peak of a (220) field origin, by using a catalyst having crystallite size smaller than 2.0 nm, poisoning by intermediate products can be reduced, so that, high active fuel cell catalyst can be obtained. COPYRIGHT: (C)2008,JPO&INPIT