Comparison of the gas sensing performance of two-dimensional materials doped with metal oxides (MoTe2, WTe2) for converter transformer discharge fault gases: A DFT study

Using two-dimensional nanomaterials to detect discharge fault gases caused by the removal and connection of converter transformer leads can correctly judge the operating status of the power system and effectively prevent the expansion of faults. In this study, density functional theory (DFT) was used to compare the detection effects of MoTe2 and WTe2 modified by CuO, Ag2O and TiO2 on four fault gases (CO, C2H2, C2H4, C2H6). Compared with the pristine substrate, the band gap value of the substrate modified by metal oxides decreased and the structure became more compact. The adsorption effect of the fault gas on the two substrates after doping was analyzed by combining adsorption distance, adsorption energy, DCD and DOS. CO and C2H4 have the best adsorption characteristics on CuO-WTe2, C2H2 performs best on CuO-MoTe2, and the adsorption performance of C2H6 is not ideal in all systems. The conductivity of the substrate adsorbed gas was further analyzed using band structure, molecular orbital theory and work function, and the feasibility of the six modified materials was compared and discussed from the perspective of sensitivity and recovery time, and corresponding conclusions were drawn. This paper provides theoretical guidance for exploring the application prospects of MoTe2 and WTe2 substrates in converter transformer fault diagnosis and prevention.