Carbon-Supported Au Catalyst in Acetylene Hydrochlorination: Enhancing Catalytic Performance by Complexation of Dicarbonyl Ligands

Graphical Acetylene hydrochlorination : Dicarbonyl ligands enhanced the dispersion of Au species, suppressed the reduction of Au cations, and reduced the formation of carbon deposits during catalytic acetylene hydrochlorination. Carbon-supported Au (Au/AC) has been proven to be one of the most promising catalysts in the field of acetylene hydrochlorination. However, the catalytic performance of conventional Au/AC catalyst is usually limited due to the unsatisfactory dispersion of active Au cation on the surface of the support, carbon deposition, and inevitable reduction to inactive Au nanoparticles. Herein, Au catalysts with highly dispersed Au cation were developed using the complexation of dicarbonyl ligand N-chlorosuccinimide (NCS) and N-methylsuccinimide (NMS). The obtained Au−NMS/AC and Au−NCS/AC catalysts with 0.1 wt.% Au loading possessed acetylene conversion of 98 % and 88 % at 180 °C and GHSV (C 2 H 2 ) of 160 h −1 , which were clearly better than that of pristine Au/AC. The characterization results showed that coordination between Au cation and ligands enhanced the dispersion of Au species, suppressed the reduction of Au cation, and reduced the formation of carbon deposits. Density functional theory (DFT) calculations suggest that Au−NMS/AC and Au−NCS/AC catalysts follow a HCl-preferred concerted addition reaction mechanism with lower reaction energy barrier. This favors the high activity and nuclearity stability of the Au center. This study provides great potential for the use of dicarbonyl ligands on Au-based catalysts in acetylene hydrochlorination.