Theoretical and experimental study on competitive adsorption of SF 6 decomposed components on Au-modified anatase (101) surface

Abstract Partial discharge inside gas insulated switchgear in electric systems will lead to the decomposition of SF 6 gas, the insulating medium, producing several kinds of characteristic components. Detecting the species and concentrations of decomposed components of SF 6 is considered a feasible way of early-warning to avoid occurrence of sudden fault. As a research hotspot in gas-sensing field, TiO 2 nanotubes possess wide application prospect in online monitoring of fault gases in gas insulated switchgear. In this paper, adsorption parameters of SO 2 , SOF 2 , and SO 2 F 2 , characteristic products of SF 6 decomposition, on Au-doped anatase TiO 2 (101) surface were calculated using software Materials Studio. The adsorption processes of gas molecules on Au-doped anatase TiO 2 (101) surface were theoretically analyzed, which can be used to explain the gas-sensing mechanism of TiO 2 nanotubes sensor. Besides, adsorption parameters of Au-doped anatase TiO 2 (101) surface were compared with those of intrinsic anatase TiO 2 (101) surface. As can be concluded, Au doping changes the sensitivity and selectivity of TiO 2 nanotubes to the above three kinds of gases. Furthermore, gas-sensing experiment of intrinsic and Au-doped TiO 2 nanotubes to SO 2 , SOF 2 , and SO 2 F 2 was carried out, of which the results were consistent with simulation analysis. Research of this paper illustrates sensitive and selective changes of TiO 2 nanotubes gas sensor after Au doping, which lays foundation for preparation of gas sensors applied for detection of partial discharge inside gas insulated switchgear.