The influence of trace oxygen on the initial defluorination stage of SF6 conversion catalyzed by TiO2(1,1,0)

With the widespread application of new environmentally friendly insulating gases in high-voltage power equipment, the large amounts of existing SF6 in such equipment will gradually be phased out, highlighting the challenges of its recovery and degradation. Metal oxide catalysts, possessing abundant surface-active sites and thermal stability, offer promising potential for the efficient degradation of SF6. This study focuses on the theoretical investigation of the initial process of TiO2-catalyzed SF6 conversion. Using density functional theory and transition state theory, the study explores the adsorption and defluorination processes of SF6 on the TiO2(1,1,0) surface and analyzes the impact of trace O2 on the catalytic defluorination process. The research reveals that during the adsorption phase, O atoms generated from the high-temperature decomposition of O2 compete for the adsorption sites on the TiO2(1,1,0) surface with SFX (x = 1,2, …, 6), thereby inhibiting the adsorption of SF6 and its low-fluorine sulfur compounds on the catalyst surface. In the defluorination phase, TiO2 can effectively reduce the energy barrier for the defluorination process of SF6, and in an oxygen environment, the energy barrier for the stepwise defluorination of SF6 on the TiO2(1,1,0) surface is lowered. This indicates that an appropriate amount of O2 can enhance the TiO2(1,1,0) catalytic conversion of SF6. The results of this study provide theoretical references for the industrial application of harmless conversion of SF6 waste gas.