FINE PARTICLE OF PEROVSKITE OXIDE, PARTICLE HAVING DEPOSITED PEROVSKITE OXIDE, CATALYST MATERIAL, CATALYST MATERIAL FOR OXYGEN REDUCTION, CATALYST MATERIAL FOR FUEL CELL, AND ELECTRODE FOR FUEL CELL

摘要

A catalyst for electrodes in solid-polymer fuel cells whichcomprises metal oxide particles. It can be used as asubstituent for carbon particles having platinum depositedthereon and platinum metal particles which are presently ingeneral use. The catalyst comprises fine transition-metaloxide particles having, in the main phase, a perovskitestructure represented by the general formula ABO3 (wherein Arepresents one or more elements selected among lanthanum,strontium, cerium, calcium, yttrium, erbium, praseodymium,neodymium, samarium, europium, silicon, magnesium, barium,niobium, lead, bismuth, and antimony; and B represents one ormore elements selected among iron, cobalt, manganese, copper,titanium, chromium, nickel, and molybdenum), the fine oxideparticles having lattice constants satisfying the followingrelationship (1):1.402 2b/(a+c) 1.422 (1)wherein a and c represent the minor-axis lengths of theperovskite type crystal lattice and b represents the major-axis length thereof.