Adsorption of SF(6) decomposed gas on anatase (101) and (001) surfaces with oxygen defect: A density functional theory study

The detection of partial discharge by analyzing the components of SF(6) gas in gas-insulated switchgears is important to the diagnosis and assessment of the operational state of power equipment. A gas sensor based on anatase TiO(2) is used to detect decomposed gases in SF(6). In this paper, first-principle density functional theory calculations are adopted to analyze the adsorption of SO(2), SOF(2), and SO(2)F(2), the primary decomposition by-products of SF(6) under partial discharge, on anatase (101) and (001) surfaces. Simulation results show that the perfect anatase (001) surface has a stronger interaction with the three gases than that of anatase (101), and both surfaces are more sensitive and selective to SO(2) than to SOF(2) and SO(2)F(2). The selection of a defect surface to SO(2), SOF(2), and SO(2)F(2) differs from that of a perfect surface. This theoretical result is corroborated by the sensing experiment using a TiO(2) nanotube array (TNTA) gas sensor. The calculated values are analyzed to explain the results of the Pt-doped TNTA gas sensor sensing experiment. The results imply that the deposited Pt nanoparticles on the surface increase the active sites of the surface and the gas molecules may decompose upon adsorption on the active sites.