CoO-SnSe monolayer: A high potential candidate for SF6 characteristic decomposition gas adsorption and detection

Abstract

Insulation performance testing of gas-insulated switchgear (GIS) and treatment of SF6 decomposition products under partial discharge are two crucial studies. In this paper, the adsorption behavior and sensor properties of five characteristic decomposition gases of SF6 (HF, H2S, SO2, SOF2, SO2F2) on intrinsic and CoO-doped SnSe monolayers are investigated in detail based on density-functional theory. The results showed that the adsorption behaviors of HF, H2S, SOF2 and SO2F2 on SnSe monolayers were all physisorption among which the best adsorption was SO2 with an adsorption energy of −0.618 eV, which is a weak chemisorption. After doping with CoO, the adsorption capacity of SnSe monolayer for five gases was significantly enhanced, in which the adsorption energies for SO2 and SOF2 reached −1.356 eV and −1.175 eV, respectively. In addition, the conductivity of the system is greatly improved, with the bandgap changing from 1.129 eV to 0 eV. The microscopic mechanism of the interaction of gas molecules with CoO-SnSe monolayers has been revealed by energy band structure (Eg), density of states (DOS), Milligan charge analysis (∆Q) and electrostatic potential. Finally, the sensitivity (S) and desorption time (τ) of the five adsorption systems were calculated to illustrate the macroscopic gas-sensitive properties of the system. This work will help to explore the application of CoO-SnSe monolayers in SF6 decomposition gas sensing detection and adsorption treatment.