| 摘要 |
PROBLEM TO BE SOLVED: To provide a cerium-zirconium type complex oxide which allows a pyrochlore phase to be present stably in a crystal structure even when exposed to high temperatures for a long time and is high in OSC and excellent in exhaust gas purification performance and its production method.SOLUTION: A cerium-zirconium type complex oxide comprises cerium, zirconium and one or more elements selected from rare earth elements other than cerium and alkaline earth metal elements. After a 3-h heat treatment at 1,000-1,100°C, (1) its crystal structure contains a pyrochlore phase; (2) it has a value of {I111/(I111+I222)}×100 of 1 or greater, with the peak intensity of the (111) plane taken as I111 and the peak intensity of the (222) plane as I222; and (3) it has an oxygen absorption/emission capacity at 450°C of 0.01 mmol/g or higher, an oxygen absorption/emission capacity at 600°C of 0.05 mmol/g or higher and an oxygen absorption/emission capacity at 750°C of 0.30 mmol/g or higher. |
