The Selective Oxidation Of Vinyl Chloride On Different Metal Surfaces: A DFT Study

Vinyl ch]oride(VC) is versatile intermediates for chemical synthesis, especially, poly-vinyl chloride(PVC). With the development of vinyl chloride processing, its damages become more and more serious for both humen and ozonosphere. The partial oxidation of vinyl chloride on different metal surfaces is one of asymmetric molecules oxidation reaction. Although a tremendous amount of work has accumulated in the literature regarding the reaction of ethylene to ethylene oxide, the detailed selective oxidation mechanism for the asymmetric molecules is insufficient. In the present work, we give a systemic density functional calculation of vinyl chloride selectivity oxidation on some oxygen preadsorbed metal surfaces, Ag(111), Pt(111), Rh(111) and Ag(100), intend to understand the mechanism of this reaction.All calculations were carried out using the Vienna ab initio simulation package(VASP) code. In order to model the metal surfaces, a periodical array model containing four atomic layers was used. The project-augment wave (PAW) method was used to describe the inner cores, and the electronic wave functions of the valence electrons were expanded on a plane wave. The exchange-correlation functional used to obtain the energy was the Perdew-Wang (PW91) implementation of the generalized gradient approach, and a climbing-nudged elastic band method (cNEB) was used for locating the transition state (TS), the frequency analysis was performed to confirm the transition state.The main conclusions of this work are summarized as follow:(1) The calculated results indicated that fcc site was the most steady adsorption site of O atom on Ag(111), Pt(111), Rh(111). The order of the adsorption energies is:Ag(111)