Store and release of oxygen of ceria-zirconia solid solution synthesized by solid phase reaction at near room temperature

Abstract

Capability of oxygen store and release of ceria-zirconia solid solution made by attrition mill process was measured by thermo-gravimeter with 1 mass% of Pt. Ceria-zirconia solid solution made by conventional heating method of ceria powder with zirconium salt was also characterized for comparison. Capability of oxygen store and release of ceria-zirconia solid solution made by attrition mill process is about three times larger than that of conventionally made samples. And, the point, where zirconium content is 100% on the relation between capability of oxygen store and release and zirconia content in the ceria-zirconia solid solution, corresponds to the state in which the valence of all the cerium ion being contained in the solid solution is 3. This fact suggests that the mechanism, that the increase of capability of oxygen store and release by dissolving zirconia into ceria, is that zirconium ions, which are smaller than cerium ions of the valence 4, release the strain caused by the expansion due to a reduction of cerium ions.