First-Principles Study on the Effects of Ag ₂ O-, TiO ₂ -, and NiO-Modified PtSe ₂ on the Gas Adsorption Characteristics of a Transformer Arc Discharge Fault

The operating status of a transformer is crucial to the safety and reliability of the power system. When the internal insulation fails, arc discharge may occur, which could seriously threaten the stable operation of the power system. Therefore, monitoring the gas dissolved in the oil during the transformer fault is greatly significant for its safe operation. In this study, three metal oxides (Ag₂O, TiO₂, and NiO) are doped into intrinsic PtSe₂, which significantly improved its adsorption affinity for four fault gases (H₂, C₂H₂, C₂H₄, and CH₄). The electronic properties and sensing properties during gas adsorption are systematically analyzed based on first principles. The results indicate that the intrinsic adsorption energies of the four gases are all less than 0.25 eV. However, the conductivity of intrinsic PtSe₂ is significantly improved through the use of Ag₂O, TiO₂, and NiO, facilitating electron transfer during the gas adsorption process and effectively enhancing the adsorption performance of the gases. Among them, the Ag₂O-PtSe₂ monolayer exhibited excellent adsorption performance for C₂H₂ and C₂H₄, with adsorption energies of -0.731 and -0.933 eV, respectively. Meanwhile, the rapid desorption characteristics of the TiO₂-PtSe₂ monolayer for C₂H₄ at room temperature provide greater flexibility for its practical application. The adsorption energy of the NiO-PtSe₂/H₂ system is -1.035 eV, and it exhibits a good desorption time (12.670 s) at 398 K, demonstrating the potential of the NiO-PtSe₂ system as a gas-sensitive material. The three modified materials have excellent performance in transformer fault gas detection, laying a theoretical foundation for the development of efficient gas sensors.