Density functional studies of co adsorption on M55(M=Cu, Ag, Au) clusters

Abstract

The carbon monoxide adsorption onto the Au55, Ag55, and Cu55 clusters were comparably investigated at the all-electron relativistic BVP86/DNP levels. The charge effects of CO adsorption also were studied. The computational results indicated that CO adsorption energies on the Au55 clusters are maximum, followed by those on the Cu55 clusters, the minimum for those on the Ag55 clusters. The cluster's charge affects slightly the activation of C-O bond and the bond strength between the carbon atom of CO and the surface atoms of cluster. The CO adsorption onto the clusters results in the charge transfer from cluster to CO fragment. The activation of C-O bond is closely related to the adsorption site of CO. The activation order of C-O bond for the CO adsorption on the different site of the cluster as follows: hole site > bridge site > top site. The CO can be selectively adsorbed at the top site of Au55 clusters, while the CO adsorption on Ag55 and Cu55 clusters is non-selective.