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

[Image: see text] 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.