Abstract: The structure and oxygen mobility of Ce_1-xZr_xO₂ (0 ≤x≤ 1) samples prepared by citric acid sol-gel method were characterized by XRF, XRD, Raman, XPS, Ar+ etching-XPS and H₂-TPR. The data showed that the crystalline structure of Ce_1-xZr_xO₂ can significantly affect the oxygen mobility. When x≤0.15, the samples were found to exist as cubic Ce-Zr-O solid solutions. An increase in x resulted in a shrinking of the crystal unit volume, an increasing in the number of oxygen vacancies, and an increasing in the oxygen mobility as well. When x＞0.15, Ce_1-xZr_xO₂ existed in a mixed phases of tetragonal and cubic Ce-Zr-O solid solutions; the percentage of tetragonal phase increased, oxygen vacancies decreased and oxygen mobility reduced with increasing x in these samples. Therefore, this present work shows that oxygen mobility in the Ce_0.85Zr_0.152O₂ sample is the highest.

Key words: Ce_1-xZr_xO₂, Sol-gel method, Oxygen mobility, Oxygen vacancy, CeO₂-based solid solution