Small gas adsorption on 2D material SnSe: a first-principles study

Abstract

Abstract SnSe not only has a large surface-to-volume ratio, but also provides enough space to adsorb small-molecule gases owing to its unique wrinkled structure, so it exhibits great application prospects in gas sensing. In this study, we have comprehensively investigated the adsorption properties of H 2 , N 2 , CO, CO 2 , H 2 S, H 2 O, NH 3 , NO, SO 2 , and NO 2 on SnSe by the first-principles density functional theory, and have analyzed the sensing potential of SnSe for these small gas molecules. It is found that only NO and SO 2 have suitable adsorption energies, showing that they can be stably adsorbed on the SnSe substrate and easily desorbed under certain conditions. Moreover, NO adsorption introduces a magnet moment that can be differentiated from SO 2 and NO 2 . Additionally, according to the calculation results of the statistical thermodynamics model and nonequilibrium Green’s function method, SO 2 possesses enormous adsorption density and larger current than NO under the same condition. Therefore, SnSe is promising for reversible SO 2 sensing.