OXYGEN ABSORBING AND RELEASING MATERIAL

PROBLEM TO BE SOLVED : To provide an oxygen absorbing and releasing material composed of a ceria-zirconia-based composite oxide as a cubic crystal system (a fluorite type crystal structure) in which the content of Ce is 30 mol% or more and the Ce utilization factor is 90% or more. SOLUTION : There is provided an oxygen absorbing and releasing material which is a ceria-zirconia-based composite oxide, CexZr1-x-yMyO2-y/2, where the content x of Ce is more than 0.30, the content y of a substitution element M is more than 0 and 0.2 or less, the substitution element M includes rare earth-elements and alkaline earth metal elements excluding at least three kinds of Ce having an ionic radius larger than that of Ce4+ ions, the composite oxide is a cubic crystal system and the lattice constant a of crystals is 534 pm or more. SELECTED DRAWING : Figure 2 COPYRIGHT : (C)2018, JPO&INPIT