Mechanisms for Catalytic CO Oxidation on SiAu(n) (n = 1–5) Cluster

Significant progress has been made in understanding the reactivity and catalytic activity of gas-phase and loaded gold clusters for CO oxidation. However, little research has focused on mixed silicon/gold clusters (SiAu(n)) for CO oxidation. In the present work, we performed density function theory (DFT) calculations for a SiAu(n) (n = 1–5) cluster at the CAM-B3LYP/aug-cc-pVDZ-PP level and investigated the effects on the reactivity and catalytic activity of the SiAu(n) cluster for CO oxidation. The calculated results show that the effect is very low for the activation barriers for the formation of OOCO intermediates on SiAu clusters, SiAu(3) clusters, and SiAu(5) clusters in the catalytic oxidation of CO and the activation energy barriers for the formation of OCO intermediates on OSiAu(3), OSiAu(4), and OSiAu(5). Our calculations show that, compared with the conventional small Au cluster, the incorporation of Si enhances the catalytic performance towards CO oxidation.