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

The activity of a V 2 O 5 /TiO 2 -Al 2 O 3 catalyst for oxidative dehydrogenation of ethylbenzene to styrene with various V 2 O 5 loadings in the presence of CO 2 and N 2 was studied. Among the different loadings of V 2 O 5 , the 5 wt% V 2 O 5 /TiO 2 -Al 2 O 3 catalyst exhibited better activity. The incorporation of TiO 2 into the Al 2 O 3 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 CO 2 . The conversion directly depends on the availability of active V 5+ 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 H 2 -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. A stable V 2 O 5 /TiO 2 -Al 2 O 3 catalyst was synthesized for the oxidative dehydrogenation of ethylbenzene to styrene using CO 2 as a mild oxidant.