Effects of Al doping on CeZr solid solution for oxidative dehydrogenation of ethylbenzene with CO2

For improving the oxygen storage/release capacity of ceria-zirconia solid solution, Ce0.5Zr0.5O2-Al2O3 mixed oxides were prepared by a co-precipitation method and applied in the oxidative dehydrogenation of ethylbenzene to styrene with carbon dioxide. Ce0.5Zr0.5O2-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 Ce0.5Zr0.5O2 crystallite size, increases the specific surface area and oxygen storage capacity of Ce0.5Zr0.5O2-Al2O3 mixed oxides. The specific surface area and oxygen storage capacity of Ce0.5Zr0.5O2-Al2O3 mixed oxides are 51.8 m2/g higher and 69.4 μmol/g more than those of Ce0.5Zr0.5O2 mixed oxides. The ethylbenzene conversion over Ce0.5Zr0.5O2-Al2O3 mixed oxides is about 10% higher than that over Ce0.5Zr0.5O2 mixed oxides after 5 h reaction.