Abstract:The adsorption and sensing properties of Cu-modified monolayer NiS2 (Cu-NiS2) for five C5F10O decomposition components are studied by first-principles to explore its application potential in the field of evaluation of operating status of C5F10O insulation devices. Through the study of adsorption parameters of each adsorption system, it is found that Cu-NiS2 exhibits chemical adsorption on C2F6O3 molecules with an adsorption energy of -1.05 eV, while it exhibits physical adsorption on C3F6, CF2O, C2F6 and CF4 molecules. Through the analysis of electronic properties and gas sensitivity recovery characteristics of each adsorption system, it is found that Cu-NiS2 has better sensing performance for C3F6 or CF2O gas, and has better recovery performance at room temperature, so it has a great potential to be developed as a C3F6 or CF2O gas sensor. On the contrary, due to the poor sensing performance of Cu-NiS2 for C2F6 and CF4, high-sensitivity detection of these two gases cannot be achieved. In addition, although Cu-NiS2 has excellent sensing performance for C2F6O3, its long recovery characteristics determines that it can only achieve a single detection of the gas, and cannot achieve the long-term stable use. According to theoretical simulation research, Cu-NiS2 as a new type of gas-sensing material for power system fault diagnosis is proposed, which is of great significance for evaluating the operating status of C5F10O insulation devices.