1. Ultra High Voltage Company, State Grid Gansu Electric Power Company, Lanzhou 730070, China
2. Power Research Institute, State Grid Gansu Electric Power Company, Lanzhou 730070, China
et al.
Developing gas sensitive materials with excellent performance is one of the effective strategies to accurately detect SF6 decomposition characteristic components and evaluate the operation of electrical equipment. The adsorption properties of graphitic carbon nitride (g-C3N4) for SF6 decomposition gases (H2S, SO2, SOF2 and SO2F2) were studied based on firstprinciples. The evolution laws of adsorption energy, differential charge, electrostatic potential, LUMO/HOMO orbitals, electronic properties and work function of g-C3N4 before and after adsorption of gas molecules were systematically investigated. The results showed that the adsorption effects of g-C3N4 for SO2, SOF2 and SO2F2 were significantly better than that for H2S. After adsorption of SO2F2, g-C3N4 had electron transfer towards SO2F2 molecule, and the interaction between neighboring atoms was relatively stronger, which tended to chemisorption. The LUMO/HOMO energy levels of adsorption systems were higher than that of gas molecules, and the adsorption systems tended to be stable after adsorbing gas molecules. The desorption difficulty after gas adsorption reaction was SO2,H2S, SOF2, SO2F2 in order. The work function calculation result showed that gC3N4 had enhanced electron binding ability after adsorption of gas molecules, however, there were differences in binding ability. Therefore, g-C3N4 has high selectivity for SF6 decomposition characteristic gases detection. This study can provide a theoretical basis for the application of g-C3N4 in the detection of SF6 decomposition characteristic components.