Computationally tailoring the adsorption behavior of ZrSe2 for SF6 decomposition species in GIS: Mechanistic insights into Cu2O/Ag2O functionalization.

Serving as an essential insulating gas, sulphur hexafluoride (SF6) is applied in gas-insulated switchgear (GIS) and exerts a key effect on insulation and arc suppression. When the electrical and mechanical breakdowns occurred, SF6 decomposition can lead to the formation of H2S, SO2, SO2F2, and SOF2. Adsorption effect of transition-metal oxides modified ZrSe2, including Cu2O-ZrSe2 and Ag2O-ZrSe2 towards sensing gases during SF6 decomposition in this study was analyzed using the first-principles simulation. The optimized structures were determined, presenting advantages over initial ZrSe2 containing binding energy, band gap and electron transfer. After ensuring the most stable modification, the performance of the four most stable modified structures toward gas adsorption was studied, meanwhile the analysis was conducted through calculating parameters including adsorption energy (Eads), charge transfer (QT), adsorption distance (D), density of states (DOS), energy band gap (Eg), differential charge density (DCD) and recovery time (τ). Through analysis of parameters, what can be found is that adsorptions of initial ZrSe2 to four gases are physical and spontaneous adsorption on the substrate is difficult to achieve. In contrast, after modified by the transition-metal oxides (Cu2O and Ag2O), the adsorption performances toward four gases are proved as chemical adsorption behaviors. Finally, the adsorption performance of Cu2O-ZrSe2 for four gases is SO2 > H2S > SO2F2 > SOF2 while Ag2O-ZrSe2 is SO2 > SOF2 > SO2F2 > H2S. Besides, although the strong adsorption of SO2 results in a long recovery time, limiting the material application as a reusable sensor for this gas. The calculation results offer perspective materials for detecting SF6 decomposition gases in GIS generated by especially partial discharge.