Abstract
Molybdenum based oxide catalysts Mo-H, Mo-Fe, Mo-Ce, and Mo-Sn were prepared by calcining H3PMo12O40, Fe1.5PMo12O40, Ce1.5PMo12O40, and Sn1.5PMo12O40 heteropolyanion precursors at 700 degrees C, respectively. The prepared oxides have been characterized and tested for the dehydrogenation of isobutane (IB) to isobutene in the presence of CO2. The effects of temperature, time on stream, and CO2/IB ratio were investigated. It was found that alpha- and beta-moO(3) phases were present in all catalysts. Catalytic tests showed that increasing the reaction temperature increased both the conversion and isobutene selectivity, whereas increasing the CO2/IB molar ratio increased the conversion but decreased the selectivity for isobutene. Iron was found to be an effective additive element for the enhancement of catalytic activity compared with Ce and Sn.