MANGANESE OXIDE EXCELLENT IN OXYGEN STORAGE ABILITY, VARIOUS MATERIALS INCLUDING THE OXIDE, METHOD AND APPARATUS USING THE OXIDE

PROBLEM TO BE SOLVED: To provide an inexpensive and practical metal oxide featured by (a) being provided with a large oxygen-storage capacity and chemical stability in a high temperature region; (b) being provided with an oxygen-releasing function different from that of CZ (CeO2-ZrO2), i.e. a function absorbing and releasing oxygen by only temperature changes; and (c) comprising no expensive element as constituting components; as a substance applicable to a catalyst material for emission gas purification, a catalyst material of oxygen-reducing agent, a positive-electrode material of a solid oxide fuel cell, an oxygen separator, an oxygen remover, an oxygen selector, an oxygen enricher or the like. SOLUTION: This manganese oxide excellent in oxygen storage capacity has oxygen absorbing and releasing characteristics functioning by only temperature changes in a temperature region ranging from 400°C to 600°C, and is expressed by the formula (1): (Ca2-xAx)(Mn2-yBy)O5+δ, wherein A is one or two or more kinds of alkaline earth metal other than Ca; B is one or two or more kinds from among Al, Fe, Co and Ga; and x, y and δ satisfy formulae 0≤x≤2, 0≤y