Abstract: For improving the oxygen storage/release capacity of ceria-zirconia solid solution, Ce_0.5Zr_0.5O₂-Al₂O₃ mixed oxides were prepared by a co-precipitation method and applied in the oxidative dehydrogenation of ethylbenzene to styrene with carbon dioxide.Ce_0.5Zr_0.5O₂-Al₂O₃ mixed oxides were characterized by powder X-ray diffraction, Raman spectroscopy, N₂-sorption, H₂ temperature-programmed reduction, and X-ray photoelectron spectroscopy.Results show that Al₂O₃ acts as a diffusion barrier.The addition of Al prevents the growth of Ce_0.5Zr_0.5O₂ crystallite size, increases the specific surface area and oxygen storage capacity of Ce_0.5Zr_0.5O₂-Al₂O₃ mixed oxides.The specific surface area and oxygen storage capacity of Ce_0.5Zr_0.5O₂-Al₂O₃ mixed oxides are 51.8 m²/g higher and 69.4 μmol/g more than those of Ce_0.5Zr_0.5O₂ mixed oxides.The ethylbenzene conversion over Ce_0.5Zr_0.5O₂-Al₂O₃ mixed oxides is about 10% higher than that over Ce_0.5Zr_0.5O₂ mixed oxides after 5 h reaction.