Single-Atom Au^I–N₃ Site for Acetylene Hydrochlorination Reaction

Abstract

The gold-catalyzed acetylene hydrochlorination reaction is an important process to produce vinyl chloride monomer in the polyvinyl chloride industry. The traditional catalyst of carbon-supported AuCl3 is inclined to be reduced by acetylene and lose its activity during the reaction process. Here, we presented the construction of AuI–N3 active sites through single gold atom dispersed on g-C3N4 (Au1/g-C3N4), which shows robust catalytic performance toward acetylene hydrochlorination. The Au species is shown to have AuI oxidation state, and it is coordinated with three nitrogen atoms of tri-s-triazine repeating units, which is consistent with density functional theory (DFT) modeling and XAFS measurements. Through DFT study, we demonstrate that the AuI–N3 sites tend to coordinate with HCl than C2H2 in the initial reaction. The AuI–N3 sites cannot be reduced into Au0 oxidation state easily and thus maintain their activity as stable catalytic active sites. The single-atom-site Au catalyst with nitrogen coordination environment and corresponding electronic state provides an efficient pathway for acetylene hydrochlorination reaction.