DFT study of SF₆ decomposition species adsorption on Ni-doped InSe Monolayer: Insights into gas sensing performance

This study employs first-principles calculations to investigate the gas sensing behavior of a Ni-doped indium selenide (InSe) monolayer toward four SF₆ decomposition products: H₂S, SO₂, SOF₂, and SO₂F₂. Structural optimization, AIMD, and vibrational analyses confirm the thermal stability of the Ni-InSe monolayer. Adsorption results indicate strong chemisorption for H₂S and SO₂, weak chemisorption for SOF₂, and physisorption for SO₂F₂. Notably, SOF₂ and SO₂F₂ exhibit high sensing responses (-99.5 % and -80.1 %) and rapid recovery times (6.61 × 10^-3 s and 2.84 × 10^-5 s) at room temperature, suggesting excellent reusability and selectivity. Although H₂S and SO₂ have longer recovery times at ambient temperature, their detection becomes effective at elevated temperatures. These findings highlight the potential of Ni-InSe monolayer as a stable, sensitive, and selective gas sensor for monitoring hazardous SF₆ byproducts in gas-insulated switchgear (GIS) systems.