Gas-sensing properties of Pb, Pd modified C3N4 for SF6 decomposition products detection: A DFT study

Abstract

The detection of SF6 decomposition products plays an important role in the diagnosis and evaluation of the discharge faults of SF6 insulation equipment. The effects of Pb/Pd modification on the gas-sensing properties of C3N4 material to H2S, SO2, SOF2, and SO2F2 were studied. The adsorption capacity of pristine C3N4 to SF6 is very weak or even does not react. Pb/Pd significantly improves the conductivity and gas sensitivity of C3N4. The adsorption performance of Pb-C3N4 and Pd-C3N4 on SF6 decomposition products is significantly improved, and the reaction rate is fast. The conductivity of the adsorption system changes obviously after the adsorption of four gases. The types and concentrations of SF6 decomposition products can be identified according to the varying degrees of electrical conductivity. The band gaps of Pd-C3N4 adsorption systems after H2S, SO2, SOF2, and SO2F2 adsorption are 0.019 eV, 0.024 eV, 0.023 eV, and 0.007 eV, respectively. This study provides an effective method for online diagnosis and evaluation of discharge faults of SF6 insulation equipment.