DFT study on the adsorption of CO, NO2, SO2 and NH3 by Te vacancy and metal atom doped MoTe2 monolayers

Based on the first-principles calculation, the adsorption structure and electronic characteristics of CO, NO2, SO2 and NH3 adsorbed on pure, defective and metal atom doped MoTe2 monolayer were systematically studied. The original MoTe2 monolayer and MoTe2 monolayer containing Te defects can be used as room temperature gas sensors to detect NO2 gas and SO2 gas, and the adsorption effect can steadily increase in the simulated working environment. The adsorption behaviors of Ag, Pd and Rh atoms with different doping methods were studied. The calculation results show that the conductivity and chemical activity between metal atoms and gas is improved after doping, resulting in tremendous adsorption energy and charge transfer. Due to the changes in the energy band structure, the density of states, work function and recovery time after adsorption, different doped systems show the potential of high-performance gas sensors at room temperature and high temperature. The research results are significant to the gas sensing mechanism of the modified MoTe2 monolayer and helpful in exploring the modified MoTe2 monolayer as a sensing material and gas scavenger.