Adsorption of SF6 Decomposed Products over ZnO(101̅0): Effects of O and Zn Vacancies.

Abstract

We carried out a density functional theory study to investigate the adsorption behavior of four kinds of SF6 decomposed products over the ZnO(101̅0) surface. The effects of O and Zn vacancies on the surface were also considered. For perfect ZnO(101̅0) surface, the adsorption of SO2 and H2S exhibits stronger chemical interactions compared to the adsorption of SOF2 and SO2F2. For SO2 and H2S adsorption, there may exist new chemical bond formation between the molecule and the surface and the H2S molecule experiences one H–S broken bond. The introduction of O vacancy cannot obviously enhance the chemical interactions between these four molecules and the surface. However, the Zn vacancy on the surface can significantly elevate the chemical interactions between SO2/H2S and the surface. The two-coordinated O atom (O2c) on the surface plays an important role. For SO2 and H2S adsorption, the S atom in SO2 or H2S tends to bond to the O2c atom, bringing much larger adsorption energy compared to the adsorption over the perfect ZnO(101̅0) surface. This work can provide a basis for surface modification of ZnO in applications to detecting SF6 decomposed products by theoretical evaluation.