The effect of support reducibility on the stability of Co/CeO2 for the oxidative steam reforming of ethanol

Ceria plays an active catalytic role in removing carbon from the catalyst by a support-mediated cleaning mechanism. Increasing the support surface area using a novel preparation method led to improved catalyst stability and a lower coking rate. DRIFTS of adsorbed ethanol shows that oxygen from the support facilitates the formation of acetate intermediate species, thus demonstrating the ability of the support to donate oxygen. This oxygen may come from either O adatoms by adsorption of O2 at vacancies, whereby the cerium atoms involved are Ce4+. Or, it may come from vacancy-associated Type II bridging OH groups, where the cerium atoms involved are Ce3+. The higher oxygen/OH group mobility of high ceria surface area promotes the mechanism of carbon removal, which in turn contributes to the high stability of Co/CeO2 catalyst.