Engineering Hydrogen Halide Leak Sensing on Metal-Modified InSe Monolayers: Distinct Roles of Mo and W

Leakage of corrosive hydrogen halides (HCl, HBr, HI) poses severe environmental and safety risks in industrial processes, necessitating high-performance sensor materials with balanced adsorption-desorption properties. Herein, we systematically investigate the hydrogen halide sensing performance of pristine and Ir/Mo/W-decorated InSe monolayers using first-principles calculations. All three transition metals form thermodynamically stable configurations on InSe with binding energies of - 3.233 eV (Ir), - 3.941 eV (Mo), and - 3.337 eV (W). Pristine InSe exhibits negligible interaction with hydrogen halides, with adsorption energies ranging from - 0.239 to - 0.377 eV. Metal modification dramatically enhances adsorption strength, reducing adsorption distances from 4.160 to 4.253 Å to 2.360-2.711 Å and inducing significant electronic response. Mo-InSe achieves an optimal balance for HBr and HI detection, with room-temperature recovery times of 1.14 and 5.88 s, respectively. W-InSe shows the strongest adsorption toward all three gases and achieves suitable recovery under moderate heating (12.93 s at 328 K for HCl, 13.27 s at 378 K for HBr, 12.94 s at 358 K for HI). This work demonstrates that metal-modified InSe monolayers offer a tunable platform for hydrogen halide sensing, covering both room-temperature reusable and heat-assisted recovery applications.