Ethylbenzene to styrene over alkali doped TiO2-ZrO2 with CO2 as soft oxidant

Oxidative dehydrogenation of ethylbenzene (EB) to styrene monomer (SM) over alkali metal (Na, K) doped TiO2-ZrO2 (TZ) has been studied. The EB and CO2 conversions observed over alkali doped TZ are higher than that of non-doped TZ. The enhanced CO2 conversion compared with non-doped counterparts is attributed to improved basicity, formation of TiZrO4 phase with increased CO2 affinity and insertion of K or Na into the lattice which affects the binding energy of O in turn providing more labile oxygen species. Alkali doping also effected in fine tuning the surface acid base properties. Moreover, these K and Na doped binary metal oxides system showed high surface area of 256 m(2)/g and 199 m(2)/g respectively. There was a 10-fold increase in the CO2 conversions in case of the doped TZ compared to non-doped TZ increasing the stability of the catalyst by decreasing coking on the surface of the catalyst in spite of the high conversions. (C) 2015 Elsevier B.V. All rights reserved.