Computationally tailoring the adsorption behavior of ZrSe₂ for SF₆ decomposition species in GIS: Mechanistic insights...

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 (E_ads), charge transfer (Q_T), adsorption distance (D), density of states (DOS), energy band gap (E_g), 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.