Adsorption of SF₆ Decomposition Products by the S Vacancy Structure and Edge Structure of SnS₂: A Density Functional...

Detecting the composition and concentration of SF₆ decomposition products is an effective method to evaluate the state of gas-insulated switchgear. Based on density functional theory, in this work we investigated the adsorption properties of four typical SF₆ decomposition products (H₂S, SO₂, SOF₂, SO₂F₂) on an SnS₂ S vacancy structure (SnS₂-S_v) and SnS₂ edge structure (SnS₂-edge). By calculating the adsorption energy, charge transfer, and comparing the density of states (DOS) of each system before and after the adsorption of gas molecules, the physical and chemical interactions between SnS₂ with different structures and gas molecules were investigated. The results show that SnS₂-S_v has the largest adsorption energy for SO₂ and has obvious chemical interactions. The S vacancy can effectively capture an O atom in SO₂, causing SO₂ to firmly adsorb in the S vacancy. In addition, the adsorption of the four gases on the SnS₂-edge is physical adsorption, in which the 50% S edge structure has the largest adsorption energy for H₂S, reaching -0.52 eV, and there is also a large charge transfer between the 50% S edge structure and H₂S. Although the adsorption energy of SnS₂-edge to the four gases is smaller than SnS₂-S_v, it is still greater than the pristine SnS₂. This paper explores the adsorption properties of SnS₂-S_v and SnS₂-edge for SF₆ decomposition products, providing insights for the development of SnS₂-based gas sensors.