Influence of SBA-15 support on CeO2-ZrO2 catalyst for the dehydrogenation of ethylbenzene to styrene with CO2

Pure oxides of ceria (CeO2) and zirconia (ZrO2) were prepared by precipitation method and a catalyst comprising of 25 mol% of CeO2 and 75 mol% of ZrO2 (25CZ) mixed metal oxide was prepared by co-precipitation method and also a catalyst with 25 wt% of 25CZ (25 mol% of CeO2 and 75 mol% of ZrO2) and 75 wt% SBA-15(25/25CZS) was prepared by precipitation-deposition method. Aqueous NH3 solution was used as a hydrolyzing agent for all the precipitation reactions. These catalysts were characterized by X-ray diffraction and nitrogen adsorption-desorption techniques for the confirmation of SBA-15 structural intactness. All these catalysts were found to be effective for the oxidative dehydrogenation of ethylbenzene (ODHEB) to styrene in the presence of CO2 and also it was observed that there was a sequential enhancement in the catalytic activity from individual oxides to mixed oxides followed by supported mixed oxide catalysts. Of the catalysts studied in this work, the supported 25/25CZS catalyst exhibited the superior activity, which was about 10-20 times higher than the activity of bulk single oxides in terms of turn over frequency. (c) 2006 Elsevier B.V. All rights reserved.