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

Abstract

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.