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 T_Mo 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.