An efficient sensor for SF6 decomposition products by TiO2 decorated α-AsP monolayer: Theoretically evaluating GIS device safety

The efficient detection of sulfur hexafluoride (SF6) has become an important means for the stability and security of gas-insulated switchgear (GIS) devices. In this paper, we theoretically researched the possibility of α-AsP monolayer and TiO2-decorated α-AsP detecting SF6 decomposition gases using the DFT calculations. Firstly, we verified the stability of TiO2–AsP monolayer. The geometric configurations of α-AsP, TiO2-decorated α-AsP and SF6 decomposition products (HF, SO2, SOF2 and SO2F2), adsorption and sensing properties, and electronic character of adsorption systems were systematically discussed. The results show that the pristine α-AsP monolayer exhibits weaker adsorptions for HF and SO2F2. The decoration of TiO2 atom significantly enhances the electronic activity of pristine α-AsP. There is a 7.67-fold increase in the adsorption ability from α-AsP to TiO2–AsP. Moreover, the adsorption capacity was found to be in order as SO2 > SOF2 > SO2F2 > HF. Especially, the SO2/TiO2–AsP system showed efficient adsorption and sensing properties with adsorption energy of −2.146 eV and charge transfer of 0.204 e, based on the density of states, differential charge density and work functions. The electronic and recovery property analyses demonstrate the promising potential of the TiO2–AsP monolayer as a reusable sensor for detecting HF, SOF2, and SO2F2 gases at room temperature, as well as a highly sensitive one-shot sensor for SO2. At an elevated temperature of 898 K, the TiO2–AsP monolayer exhibits favorable desorption behavior for HF, SO2, SOF2 and SO2F2 gases. This work is meaningful to utilize a potential SF6 decomposition sensing nanomaterial for evaluating the safe operation of GIS devices.