Transition Metal (Rh, Pd, and Pt) Doped SnS₂ Monolayer as Promising Work Function Gas Sensors for H₂Se Detection: A DFT Study

The exploration of hydrogen selenide (H2Se) gas sensor is crucial for human and environmental safety in semiconductor manufacturing and coal gasification processes. In this study, density functional theory (DFT) was employed to investigate the adsorption and sensing properties of pristine and transition metal (TM) (Rh, Pd, and Pt) doped SnS2 (TM-SnS2) monolayer toward H2 Se. The physical stability of TM-SnS2, adsorption energies, electron transfer and distribution, chemical interactions, and overall sensing performance were examined. The results indicate that all three TM-SnS2 structures exhibit physical stability, as evidenced by their larger binding energies compared to their bulk phases. The introduction of TM atoms significantly enhances both adsorption energy and electron transfer. Moreover, all three TM atoms display strong chemical interactions with the Se atom, with adsorption on Rh and Pt sites showing a high potential for new bond formation. As work function-based gas sensor, all three TM-SnS2 exhibit a clear response to H2Se. When considering the operating environment under air condition, only Rh-SnS2 and Pt-SnS2 can detect 50 ppb of H2Se. Overall, Rh-SnS2 and Pt-SnS2 are proposed as promising candidates for H2Se sensing applications in industrial and environmental monitoring.