Excess Copper Chloride Induces Active Sites over Cu-Ligand Catalysts for Acetylene Hydrochlorination

Active sites on ligand-enhanced Cu-based catalysts for acetylene hydrochlorination have not been clearly identified yet due to their complex nature and dynamic evolution under working conditions. Herein, we correlate experimental measurements with theoretical simulations to show that the indirect ligand-coordinated sites induced by excess copper chloride are superior. The catalyst experimentally exhibits a unique dual nature that the catalytic activity could be inhibited or boosted by changing the ratio of copper chloride and ligand. By adopting molecular dynamics simulation to obtain the dynamic evolution of active sites, coupled with density functional theory calculations, we show that excess copper chloride molecules spontaneously assemble into chain structures, thus inducing indirect ligand-coordinated sites which together with the electron transfer along the copper chloride chain are crucial for the high catalytic activity. This knowledge provides fundamental insights into the origin of activity in Cu-ligand catalysts for acetylene hydrochlorination and the identification of active sites in complex catalytic systems.