DFT insights into the adsorption properties of toxic gas molecules on pure and transition metal embedded stanene monolayers: Towards gas sensor devices

Abstract The first principles calculations were conducted to gain insights into how the interactions of gas molecules can be strengthened over the stanene monolayers upon modifying the surface of stanene by transition metal incorporation. At the first stage, the structures of the transition metal adsorbed stanene monolayers were optimized to obtain the energy favorable frameworks for gas adsorption and sensing. Focused on the band structure results, we found that the Ni-adsorbed stanene monolayers represent semiconductor feature, while the Cu and Au-adsorbed ones exhibit metallic property. Various adsorption sites and directions were examined for the binding of gas molecules to the Au-adsorbed stanene systems. The Au adsorption enhances the adsorption of gas molecules on the stanene system. The difference in the electron densities indicated that the bond in the Au-embedded stanene with adsorbed gas molecules is of covalent nature for the reason that the favored electron accumulation sites are largely located at the middle of the Au-gas molecule bond. Thus, our theoretical findings suggest great potential for Au-adsorbed stanene systems as superior candidates for gas sensing.