Single-doped charged gold cluster with highly selective catalytic activity for the reduction of SO2 by CO: First-principles study**Project supported by the National Natural Science Foundation of China (Grant No. 11375091), the Natural Science Foundation of Zhejiang, China (Grant No. LY18A040003), the Natural Science Foundation of Ningbo, China (Grant No. 2018A610220), and the K.C. Wong Magna Fund in Ningbo University, China.

Abstract

It is important for environmental protection to search for catalysts with excellent performance and cost-effective to reduce SO2 by CO. In this work, using first-principles calculation, we have studied the catalytic performance of Au5Mn (M = Ni, Pd, Pt, Cu, Ag, Au; n = 1, 0, −1) clusters, and showed that, by giving a negative charge to the Au5M (M = Cu, Ag, Au, Pd) clusters, we could improve the selectivity of SO2 and avoid effectively catalyst CO poisoning simultaneously. At the same time, the catalytic reaction rate for the reduction of SO2 by CO with Au5M− (M = Cu, Ag, Au, Pd) clusters is greatly improved when the Au5M clusters are charged. These advantages can be well explained by the charge transfer between the clusters and adsorbed molecules, which means that we can effectively control the performance of the catalyst. The equilibrium structures of Au5Mn (M = Ni, Pd, Pt, Cu, Ag, Au; n = 1, 0, −1) clusters without or with adsorbed SO2 or CO molecule are also discussed, and the most stable geometrical structures of Au5Mn-ML (ML = SO2, CO, SO, and COS) can be explained very well by the match of orbitals symmetry and density of electron cloud through their frontier molecular orbitals. Considering the catalyst cost (Cu is much cheaper than Ag and Au), selectivity of SO2, and effectively avoiding the catalyst CO poisoning, we propose that Au5Cu− is an ideal catalyst for getting rid of SO2 and CO simultaneously.