First-principles investigation of gas adsorption on bilayer transition metal dichalcogenides for sensing toxic gases

• Our study identifies specific heterostructures with excellent potential for NH 3 detection. • MoS 2 /WTe 2 and MoTe 2 /WS 2 exhibit lower recovery times for NO X molecules. • MoS 2 /WTe 2 and MoTe 2 /WS 2 are selective gas sensors for both NH 3 and NO X . Transition metal dichalcogenides (TMDs) have shown significant promise in gas sensing applications due to their high catalytic activity and unique electronic properties, which facilitate effective interactions with various gas molecules. This makes them ideal candidates for high-performance gas sensors. In this study, we investigated the sensing properties of nitrogen-containing gases (NCGs) on several heterostructures—namely, MoS 2 /WTe 2 , MoTe 2 /WS 2 , MoS 2 /TiO 2 and MoS 2 /IrO 2 —using density functional theory calculations. The results indicate that NH 3 and NO X exhibit weak electronic interactions with MoS 2 /WTe 2 and MoTe 2 /WS 2 heterostructures, while strong electronic interactions are observed with MoS 2 /TiO 2 and MoS 2 /IrO 2 heterostructures. Electron transport properties were further assessed using Non-Equilibrium Green’s Function calculations, revealing promising gas sensing characteristics for NH 3 detection across all heterostructures and particularly effective NO X detection with MoS 2 /WTe 2 and MoTe 2 /WS 2 heterostructures. These findings highlight the potential of MoS 2 /WTe 2 and MoTe 2 /WS 2 as sensitive and selective gas sensors for both NH 3 and NO X , providing valuable insights for developing advanced gas-sensing technologies with diverse practical applications.