OXIDEHYDROGENATION OF ETHYLBENZENE TO STYRENE OVER ZIRCONIA-BASED CATALYSTS WITH CARBON DIOXIDE AS SOFT OXIDANT

摘要

The TiO2-ZrO2 composite oxide synthesized by a coprecipitation method was found to be in X-ray amorphous form and exhibited a high specific surface area. The XRD and RS measurements revealed that deposited vanadium and cerium oxides were in a highly dispersed form over the support surface. SEM and TEM results suggested that the dispersed V2O5 strongly interacts with CeO2 on the TiO2-ZrO2 carrier. The TPR and TPD studies revealed that reduction and desorption profiles, respectively, of the V2O5-CeO2/TiO2-ZrO2 sample were the synergetic combination of V2O5/TiO2-ZrO2 and CeO2/TiO2-ZrO2 samples and indicate the significance of vanadia and ceria addition. The TiO2-ZrO2 mixed oxide and its promoted analogues exhibit good catalytic activity and selectivity for the ODH of EB. The V2O5-CeO2/TiO2-ZrO2 composite oxide catalyst exhibited a high and stable catalytic activity and selectivity for the ODH of EB with CO2 as the oxidant. The remarkable advantage of CeO2 addition to obtain a high and stable activity has been established from this study.