X-ray absorption fine structure analysis of local structure of CeO2-ZrO2 mixed oxides with the same composition ratio (Ce/Zr=1)

Three types of CeO2-ZrO2 (Ce:Zr = 1:1 molar ratio) compounds with different oxygen storage/release capacities (OSCs) were characterized by means of the Ce K-edge and Zr K-edge X-ray absorption fine structure (XAFS). In order to investigate the relationship between the OSC and local structure, the quantitative EXAFS curve-fitting analysis was applied. By enhancing the homogeneity of the Ce and Zr atoms in the CeO2-ZrO2 solid solution, the OSC performance increased. Especially, the atomically homogeneous Ce0.5Zr0.5O2 solid solution exhibited the highest OSC among these Ceo(2)-ZrO2 samples. Additionally, the local oxygen environment around Ce and Zr was remarkably modified by enhancing the homogeneity of the CeO2-ZrO2 solid solution. It was postulated that the enhancement of the homogeneity of the CeO2-ZrO2 solid solution and the modification of the oxygen environment would be the source for the OSC improvement. (C) 2002 Elsevier Science B.V. All rights reserved.