LAUSR

The extensive applications of two-dimensional (2D) transition metal disulfides in gas sensing prompt us to explore the adsorption, electronic, optical, and gas-sensing properties of the pure and Pd-decorated GeS2 monolayers interacting with NO2, NO, CO2, CO, SO2, NH3, H2S, HCN, HF, CH4, N2, and H2 gases by using first-principles methods. Our results showed that the pure GeS2 monolayer is not appropriate to develop gas sensors. The stability of the Pd-decorated GeS2 (Pd-GeS2) monolayer was determined by binding energy, transition state theory, and molecular dynamics simulations, and the Pd decoration has a significant effect on adsorption strength and the change in electronic properties (especially electrical conductivity). The Pd-GeS2 monolayer-based sensor has relatively high sensitivity toward NO and NO2 gases with moderate recovery time. In addition, the adsorption of NO and NO2 can conspicuously change the optical properties of the Pd-GeS2 monolayer. Therefore, the Pd-GeS2 monolayer is predicted to be reusable and a highly sensitive (optical) gas sensing material for the detection of NO and NO2.