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

Active sites on ligand-enhanced Cu-based catalysts foracetylenehydrochlorination have not been clearly identified yet due to theircomplex nature and dynamic evolution under working conditions. Herein,we correlate experimental measurements with theoretical simulationsto show that the indirect ligand-coordinated sites induced by excesscopper chloride are superior. The catalyst experimentally exhibitsa unique dual nature that the catalytic activity could be inhibitedor boosted by changing the ratio of copper chloride and ligand. Byadopting molecular dynamics simulation to obtain the dynamic evolutionof active sites, coupled with density functional theory calculations,we show that excess copper chloride molecules spontaneously assembleinto chain structures, thus inducing indirect ligand-coordinated siteswhich together with the electron transfer along the copper chloridechain are crucial for the high catalytic activity. This knowledgeprovides fundamental insights into the origin of activity in Cu-ligandcatalysts for acetylene hydrochlorination and the identification ofactive sites in complex catalytic systems.