Vapor-phase dehydrogenation of ethylbenzene to styrene over a V2O5/TiO2–Al2O3 catalyst with CO2

The activity of a V2O5/TiO2–Al2O3 catalyst for oxidative dehydrogenation of ethylbenzene to styrene with various V2O5 loadings in the presence of CO2 and N2 was studied. Among the different loadings of V2O5, the 5 wt% V2O5/TiO2–Al2O3 catalyst exhibited better activity. The incorporation of TiO2 into the Al2O3 support greatly influenced the activity of the catalyst. The maximum conversion of ethylbenzene and styrene selectivity were observed to be 65% and 96%, respectively, at 550 °C and notable stability was observed up to 60 hours with CO2. The conversion directly depends on the availability of active V5+ sites. The facile redox cycle between fully oxidized and reduced V species was effective for the reaction. The catalysts were characterized by X-ray diffraction, Raman spectroscopy, BET surface area and pore size distribution, scanning electron microscopy, and H2–temperature programmed reduction. The results indicate that the surface area, interaction with the support, morphology of the catalyst and surface active sites had a significant influence on the activity.