Phosgene formation from adsorption of carbon tetrachloride on oxygen modified Ir(111)

Abstract

The production of phosgene was observed when a pure carbon tetrachloride molecular beam was impinged on an oxygen modified Ir(111) surface. We propose a mechanism involving the partial surface decomposition of the CCl 4 molecule to CCl 2 which subsequently reacts with adsorbed oxygen to form phosgene. Phosgene formation was maximized at an oxygen surface coverage of approximately 0.3 ML. Increasing the surface temperature resulted in a decrease in formation of COCl 2, as competing reactions became important, especially the rapid and more complete decomposition of CCl 4 on the surface prior to reaction with oxygen.