Atomically dispersed nano Au clusters stabilized by Zr on the TS-1 surface: Significant enhancement of catalytic oxidation ability using H2 and O2

Abstract

Au and Zr are uniformly loaded on the surface of TS-1 by coprecipitation method to obtain atomically dispersed Au-Zr binary clusters. The interaction between Au clusters, Zr and TS-1 is analyzed by Independent Gradient Model based on Hirshfeld partition (IGMH), adsorption energy of Au cluster, Mayer bond order. It is found that the existence of Zr is conducive to the stability of nano Au on TS-1 surface. The catalyst is applied to the gas phase epoxidation of C3H6 to obtain 14.06 % initial conversion, 93.93 % initial selectivity and 479.52 gPO·kgcat-1·h-1 initial productivity. It shows good stability in the continuous test for more than 50 h. Density functional theory (DFT) is used to calculate the possible catalytic reaction mechanism on the surface of atomically dispersed Au clusters. The whole process from C3H6 epoxidation reaction to catalyst regeneration is completely described. In the analysis of H2O desorption, the concept of “relay desorption” is proposed. Combined with charge and surface electrostatic potential analysis, the different attack directions of C3H6 on the catalyst surface are discussed in detail. This will provide guidance and help for the synthesis and catalytic application of nano Au catalysts.