Catalytic reduction of N2O by CO over PtlAu−m clusters: A first-principles study**Project supported by the National Natural Science Foundation of China (Grants Nos. 10804058, 11174164, and 11275100), the Science Foundation of Zhejiang Province, China (Grant No. Y607546), and the K. C. Wong Magna Foundation in Ningbo University, China.

Abstract

Based on the density functional theory, we investigate negatively charged clusters , which show significant catalytic properties in the simultaneous removal of N2O and CO. We find that in these clusters, the platinum atom acts as the adsorption center for N2O, the gold and Pt atoms act as electron donors during the reaction, and the charge transfers from the bimetallic cluster to the N2O molecule. As the proportion of Au in the cluster increases, the d band center shifts down further away from the Fermi level, meanwhile more charge is transferred to the N2O molecule, resulting in weaker N–O bond strength. Therefore bimetallic cluster shows better catalytic properties than the other clusters, especially pure Pt4− and Au4− clusters. This means that there is a synergetic effect between the Pt and Au atoms in the negatively charged bimetallic clusters. Our results help to reveal the mechanism of bimetallic clusters as excellent catalysts.