DRIFTS study of selective CO oxidation over Au/gamma- Al2O3 catalyst

In this work, the surface species and possible mechanism of selective CO oxidation over Au/Al2O3 were studied using DRIFTS method. The species observed on the surface suggested that the reaction starts with the reaction of Au-0/Au+ - OH with CO forming CO-Au-0/Au+ - OH. This complex then reacts with O-2-forming bicarbonate structure followed by formation of the second CO2 and recovery of Au-0/Au+ - OH. It was also observed that CO2 in the feed increases the formation of carbonates or carboxylates, thus reducing CO oxidation. The presence of hydrogen, on the other hand, enhances the CO oxidation due to either by direct involvement in the mechanism, or by suppressing the formation carbonate like species and preventing the deactivation of catalyst. (C) 2012 Elsevier B.V. All rights reserved.