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 CeO2–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.