Mixed oxide based on cerium and zirconium, process for its preparation; the mixed oxide containing catalyst and application of the catalyst for exhaust gas purification

摘要

A zirconium- and cerium-based mixed oxide having good thermal stability and oxidation-reduction performance, in particular, is provided. The mixed oxide which comprises zirconium and cerium is characterized in that (1) cubic phase purity of a zirconia- and ceria-based solid solution is not less than 95% by volume of the crystal phase thereof and (2) the cubic phase purity is not less than 75% by volume even after two repetitions of the step of subjecting the mixed oxide to heat treatment at 1,000 DEG C and then cooling the same to room temperature. A method of producing the mixed oxide is also provided which comprises admixing basic zirconium sulfate with a cerium ion-containing solution and then adding a base to the resulting mixed solution to thereby causing formation of a precipitate. Further, a catalyst material for exhaust gas purification comprises the oxide is disclosed, as are its use as a catalyst material, a co-catalyst or promoter and a catalyst support or carrier. IMAGE