FIRST PRINCIPLES STUDY OF HCN ADSORPTION ON GRAPHENE DOPED WITH 5D TRANSITION METAL

Abstract

Hydrogen cyanide (HCN) adsorption on graphene doped with 5d transition metal (TM) is investigated by the first principles based on density functional theory. It is observed that Hg atom cannot be doped into graphene due to saturated valence electron configurations of 5d106s2. Three kinds of HCN adsorption configurations are investigated, in which H, C and N in HCN are close to the adsorption site, respectively. The most stable adsorption configuration is obtained by total energy optimization. HCN adsorption can be studied by adsorption energy and electron density difference. HCN can only be physisorbed on Ir, Pt and Au-doped graphenes, while chemisorption is observed for Lu, Hf, Ta, W, Re and Os-doped graphenes. The band structure is calculated by B3LYP and Generalized gradient approximation (GGA) functionals. It is observed from B3LYP method that the conductivity of Lu, Hf, Re and Os-doped graphenes does not obviously change before and after HCN adsorption. Ta and W-doped graphenes change from semiconductor to metal after adsorption of HCN molecule. The results indicate that Ta and W-doped graphenes may be a promising sensor for detecting HCN. This study provides a useful basis for understanding of a wide variety of physical properties on graphene.