Reactant-Promoted Oxygen Dissociation on Gold Clusters

The molecular and dissociative adsorption of O 2 on pure odd-size Au n ( n = 1, 3, 5, 7, 9) clusters and Au n with a coadsorbed C 2 H 4 molecule has been studied theoretically using density functional theory. It is demonstrated that catalytic activation of the adsorbed O 2 on pure gold clusters in the considered size range cannot lead to O 2 dissociation. Coadsorption of C 2 H 4, however, involves an extra charge transfer from the gold cluster to O 2, energetically promoting oxygen dissociation. Our finding indicates that O 2 dissociation on the surface of small gold clusters is sensitive to the presence of other adsorbates, including the reactant molecule itself. This effect can be particularly important for understanding the mechanism of catalytic oxidation on gold clusters.