Pd-Decorated WTe 2 Monolayer as a Favorable Sensing Material toward SF 6 Decomposed Species: A DFT Study.

Based on density functional theory, this work first investigates the Pd-decorating property on the pristine WTe 2 monolayer and then simulates the adsorption performance of a Pd-decorated WTe 2 (Pd-WTe 2 ) monolayer on SO 2 and SOF 2 molecules, in order to explore its sensing potential for SF 6 decomposed species. It is found that the Pd atom can be stably anchored on the top of the W atom of the WTe 2 monolayer with a binding energy of -2.43 eV. The Pd-WTe 2 monolayer performs chemisorption on SO 2 and SOF 2 , with adsorption energies of -1.36 and -1.17 eV, respectively. The analyses of the band structure and density of states reveal the deformed electronic property of the WTe 2 monolayer by Pd-decoration, as well as that of the Pd-WTe 2 monolayer by gas adsorption. The bandgap of the Pd-Wte 2 monolayer is increased by 1.6% in the SO 2 system and is decreased by -3.9% in the SOF 2 system, accounting for the sensing response of 42.0 and -56.7% for the detection of two gases. Moreover, the changed work function (WF) in two gas systems in comparison with that of the pristine Pd-WTe 2 monolayer suggests its potential as a WF-based gas sensor for sensing two gases as well. This paper uncovers the gas sensing potential of the Pd-WTe 2 monolayer to evaluate the operation status of SF 6 insulation devices, which also illustrates the strong potential of WTe 2 -based materials for gas sensing applications in some other fields.