Bent carbon surface moieties as active sites on carbon catalysts for phosgene synthesis

Active sites in carbon-catalyzed phosgene synthesis from gaseous CO and Cl₂ have been identified using C₆₀ fullerene as a model catalyst. The carbon atoms distorted from sp² coordination in non-planar carbon units are concluded to generate active Cl₂. Experiments and density functional theory calculations indicate the formation of a surface-bound [C₆₀⋯Cl₂] chlorine species with radical character as key intermediate during phosgene formation. It reacts rapidly with physisorbed CO in a two-step Eley-Rideal-type mechanism.