DFT investigation on highly selective NO2 sensing properties of MnPS3

• For the first time, atomic-scale gases sensing mechanism of MnPS 3 is studied. • Predicted gases sensing behaviours of MnPS 3 consist with experiments. • Detection of NO 2 is related to formation of P O bond between NO 2 and MnPS 3 . • Our work provides an approach for designing MnPS 3 -based gas sensor. Among transition metal thiophosphates (MPX 3 ), p-type semiconductor MnPS 3 is considered to be a promising sensor material due to high selectivity and sensitivity to NO 2 . To explore gas sensing mechanism of MnPS 3 at atomic scale, the electronic properties of NO 2 , NH 3 , H 2 , CO, CO 2 , C 2 H 2 , H 2 S and CH 4 gases in MnPS 3 monolayer are analyzed by density functional theory. The calculated charge transfer, adsorption energy, density of state and band gap change suggest that MnPS 3 exhibits an intense sensing performance to NO 2 than other gases. Upon the adsorption of NO 2 , one of the N O bond in NO 2 breaks and a P O bond forms between NO 2 and MnPS 3 . Further, a significant increasing on DOS occurs near Fermi level, suggesting an obvious change in electric conductivity of MnPS 3 . The energy barrier and diffusion coefficient shows that the gases are easier to diffuse between adjacent vacancies on the surface of MnPS 3 , and NO 2 is relatively difficult to diffuse than other gases due to chemical adsorption. This work provides a theoretical basis for designing MnPS 3 -based NO 2 sensor.