Adsorption properties of small gas molecules on SnSe2 monolayer supported with transition metal: first-principles calculations

Abstract

The adsorption properties of CH₄, H₂S, SO₂, CO, H₂O and NO molecules on transition metal-supported SnSe₂ surface are investigated by the first-principles method. The calculation results show that the transition metal (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu) has the lowest adsorption energy when supporting at the Sn site of SnSe₂, indicating the system is relatively stable. Also, we find that CH₄, SO₂ and H₂O molecules tend to adsorb on Sc-supported SnSe₂ surface, H₂S and NO molecules prefer to adsorb on V-supported SnSe₂ surface, while CO molecule and Fe-supported SnSe₂ surfaces have strong interaction. And, CH₄, H₂S and H₂O molecules act as donors to provide electrons to the substrate, while SO₂, CO and NO molecules act as acceptors to gain electrons from the substrate. An analysis of charge difference density and density of states reveals that the adsorption energies of gas molecules are related to charge transfer and orbital hybridization. We hope that this work not only provides a promising sensor material, but also provides a new idea for the rational design of two-dimensional materials.