2015 Volume 13 Pages 129-134
CO oxidation over a rutile TiO2(110) surface supporting a tetrahedral Au10 cluster has been examined by plane-wave DFT calculations. O2 adsorbs sideon to the pentacoordinate Ti site of the oxide support with a large energy gain (∼ 2 eV), activated to a peroxide state. O2 adsorption on the cluster is much weaker. The stability and activation state of sideon O2 depends weakly on distance to the cluster. On a Ti site next to the cluster, a sideon O2 reacts with CO adsorbed on the cluster to yield CO2 with a very small energy barrier of 0.13 eV. On a more remote Ti site, a sideon O2 reacts with a gaseous CO to yield CO2 with a barrier of 0.55 eV. Thus, O2 + CO reaction is much faster at the perimeter even for a small cluster such as Au10. Similar results are obtained for a truncated pyramidal Au9, except that a carbonate is formed at the perimeter. The carbonate formation is inhibited if H2O is adsorbed next to O2. [DOI: 10.1380/ejssnt.2015.129]
