Modelling of catalytically oxidative decomposition of carbon tetrachloride on a ZnS nanocluster using density functional theory

Abstract

Using density functional theory (DFT), adsorption of O₂ and co-adsorption of O₂ and CCl₄ on (ZnS)_n clusters (n = 6, 7, 11, 12, 13, 15, 16, 17, 25, 26) and the mechanism of oxidative decomposition of CCl₄ on a ZnS nanocluster were investigated. The decomposition of CCl₄ without the ZnS cluster was also studied for comparison. The ZnS cluster achieved a significant catalytic effect during the oxidative decomposition of CCl₄. It is found that CCl₄ in gas phase undergoes a homolytic dissociation process with the activation by ZnS, reacting with O₂ to produce a CCl₃˙ radical and a ClOO˙ radical first. CO₂ and Cl₂ are identified as the final neutral reaction products, while COCl₂, CO and Cl₂O are produced as intermediates. The released energy of the total reaction, 149.83 kcal mol⁻¹, is sufficient to afford the transition energy of the cataluminescence, based on which a novel and sensitive gas sensor for the determination of CCl₄ could be constructed.