Adsorption of toxic gases by Janus MoSeTe monolayers doped with transition metals and surface defects: A first-principles study

In recent years, two-dimensional TMDs materials have been proved to be high-performance gas sensor materials. Janus material is a member of the TMD family, and its gas sensing performance research is particularly important. Gas sensing mechanism of toxic gases on transition metal dichalcogenides based Janus MoSeTe monolayers is investigated using the density functional theory. Six transition metals are considered to modify the MoSeTe surface, by comparing the adsorption energies of the transition metal on both sides of the MoSeTe monolayer, it is found that the transition metal doping is more stable on the Se side. The MoSeTe surface is activated by transition metal modification, and the gas behavior is improved by transition metal modification, it is found that Ir-MoSeTe had the best sensing performance for NO2, Os-MoSeTe had the best sensing performance for CO, and Ru-MoSeTe had the best sensing performance for H2S, NO, and SO2. After that, we explain the adsorption mechanism of gas molecules by calculating the band structure, state density, differential charge density and work function of the adsorption structure, and the recovery time explain the reuse performance of the sensor. The results show that transition metal doped MoSeTe is a promising toxic gas sensor, which provides a theoretical basis for the development of new gas sensors.