Exploration of SF6 and its decomposed gases in adsorption and sensing (four modified WSe2 monolayers at quantum level)

Abstract

As SF6 is the most widely used high-voltage insulating gas, the monitoring of its decomposition products to ensure the stable operation of GIS equipment and the treatment of leakage have been two important research topics. This work is based on the first principles of adsorption and sensing characterization of SF6 and its decomposed gases (HF, H2S, SO2, SOF2, SO2F2) using four modification strategies on the surface of WSe2. The energy parameters such as transfer charge, density of states, adsorption energy, band gap, and work function are calculated for each system. The results show that the electrical conductivity of the system is greatly enhanced when defect modification is employed, and the band gap is changed from 2.018 eV to 0.008 eV (W@WSe2) and 1.271 eV (Se@WSe2). The CoO and TiO2 doped WSe2 showed excellent adsorption of SF6 (−7.818 eV) and SOF2 (−14.263 eV), respectively, which is of great significance for SF6 gas leakage treatment. In addition, the results of work function calculations indicate that CoO-WSe2 has potential as a work function type sensor for these six gases. Finally, by calculating the desorption time (τ), we systematically explored whether the four modified materials have the characteristics to be used as recyclable resistive type sensors under different temperature environments. Our work will help to explore the adsorption performance and sensing characteristics of WSe2 monolayers with different modifications for SF6 and its decomposed gases, which is crucial for the protection of GIS equipment in power systems.