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

Abstract

A catalyst for electrodes in solid-polymer fuel cells which comprises metal oxide particles themselves. The catalyst contains fine transition-metal oxide particles having, in the main phase, a perovskite structure represented by the general formula ABO3 (wherein A represents 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 or more elements selected among iron, cobalt, manganese, copper, titanium, chromium, nickel, and molybdenum), the fine oxide particles having lattice constants satisfying the following relationship (1): 1.402<2b/(a+c)<1.422  (1) wherein a and c represent the minor-axis lengths of the perovskite type crystal lattice and b represents the major-axis length thereof.

Dependencies are inferred from the claim text.