Transition metal disulfide (MoTe2, MoSe2 and MoS2) were modified to improve NO2 gas sensitivity sensing

• MoTe 2 is a promising material for NO 2 detection. • The use of metal atom modified substrates greatly transformed the original properties. • The adsorption structures under different systems were explored as gas sensors and scavengers. For the detection of the more hazardous nitrogen oxides (NO 2 ), there is a need to find a readily fabricated, low-cost, high-performance two-dimensional material. This paper selected three transition metal disulphides (TMDs), MoTe 2 , MoSe 2 and MoS 2 , as materials for detecting NO 2 molecules by density flooding theory (DFT). The results show that the pure Mo(Te/Se/S) 2 monolayer has a poor detection effect on NO 2 molecules, and the modified monolayer exhibits better performance than its natural counterpart due to the significant electron hybridization between the dopant and the gas molecules after the introduction of metal atoms on the surface. It also leads to significant changes in electronic properties and work functions. The charge transfer mechanism based on Hirshfeld analysis shows that the charge transfer from the modified substrate to the NO 2 molecule improves the binding characteristics. And by discussing the adsorption structure, adsorption energy, local electron density, density of states, and frontier orbit theory, we show that MoTe 2 is a promising material for gas detection and removal, which will provide experimentalists with theoretical guidance for the application of Mo(Te/Se/S) 2 based sensing materials. Our work is important for predicting novel monosulfide sensing materials and extending the application of TMDs as chemical gas sensors in the field of environmental monitoring.