Abstract: A series of vanadia catalysts supported on mesocellular silica foam (MCF) with a V content ranging from 2% to 10% were studied with respect to their performance in the dehydrogenation of ethylbenzene (EB) to styrene in the presence of CO2. The structural and textural characterization of these catalysts was done using N2 adsorption, X-ray diffraction, and temperature-programmed reduction. These catalysts were found to be effective for the dehydrogenation reaction and the 6%V/MCF catalyst showed the highest activity. The MCF-supported vanadia catalysts exhibited far higher activity than their conventional V/MCM-41 counterparts, which can be attributed to the higher reduci-bility and better diffusion of reactants and products in the former catalysts. A higher conversion was obtained during EB dehydrogenation with CO2 than with N2. This is due to the oxidative dehydrogenation of EB with the help of oxygen that originates from CO2 as well as the coupling of EB simple dehydrogenation with the reverse water-gas shift reaction.

Key words: vanadia, mesocellular silica foam, supported catalyst, ethylbenzene dehydrogenation, styrene, carbon dioxide