Neutral Aun (n=3-10) clusters catalyze acetylene hydrochlorination: a density functional theory study

The mechanisms of acetylene hydrochlorination to vinyl chloride catalyzed by neutral Au3-10 clusters were systematically investigated using density functional theory with the B3LYP/LANL2DZ function. In this reaction, the gold cluster functions as a bridge of electron transfer: the electrons transfer from C2H2 to the gold cluster then from the gold cluster to HCl. HCl and C2H2 are simultaneously activated by the gold cluster, which presents a synergistic effect in co-adsorption. In the size range of Au-3 to Au-10, all gold clusters undergo the same catalytic cycle. The whole process of the acetylene hydrochlorination on the gold cluster consists of two transition states and one intermediate, and the dissociation of hydrogen chloride is the rate-controlling step. Overall, small-sized gold clusters perform better than large-sized clusters, and the odd-number atom clusters are better than even-number atom clusters.