COMPOSITE OXIDE MATERIAL AND EXHAUST GAS PURIFICATION CATALYST USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide an oxygen storage material for an exhaust gas purification catalyst having more excellent stability under high temperatures.SOLUTION: There is provided a composite oxide material which contains crystalline particles having a pyrochlore structure of a ceria-zirconia composite oxide and crystals having a pyrochlore structure of a lanthana-zirconia composite oxide present on the particle surface, wherein at least a part of the crystals of the lanthana-zirconia composite oxide is solid-solved on the surface of the crystalline particles of the ceria-zirconia composite oxide. The pyrochlore structure of the ceria-zirconia composite oxide is stabilized in the composite oxide material and the composite oxide material is suppressed in deterioration in oxygen storage capacity associated with a phase change into a fluorite structure.