Adsorption and Sensing of SF6 Decomposition Products by a Pd-Doped MoTe2 Monolayer: A First-Principles Study

The detection of sulfur hexafluoride (SF6) decomposition components has become one of the best ways to diagnose early latent insulation faults in gas-insulated equipment, which can effectively prevent sudden accidents by identifying such faults. In this paper, we by first-principles theory investigated the adsorption and sensing behaviors of four typical SF6 decomposition components (H2S, SO2, SOF2, and SO2F2) on the pristine Pd-doped MoTe2 monolayer. The adsorption energy, work function, recovery time, charge density difference, density of state, and band structure of the adsorption structures are obtained as well as analyzed. The results indicate that the Pd dopant prefers to be trapped at the TMo site, with a binding energy of −2.25 eV. The Pd-MoTe2 chemisorbs the remaining gases except SO2xF2, with the adsorption capacity ranking as SOF2 > SO2 > H2S. The adsorption of gas molecules reduces the bandgap of Pd-MoTe2, thereby increasing conductivity. On the other hand, the recovery time of the Pd-MoTe2 monolayer material at a temperature of 398 K demonstrates its excellent gas desorption performance toward four decomposition gases. The research results provide a theoretical basis for Pd-MoTe2 to detect SF6 decomposition components, thus, promoting the stable operation of the power system.