DFT study of the CO2 and CH4 assisted adsorption on the surface of graphene

Abstract

Density functional theory calculations are implemented to study the interaction of CO2 and CH4 molecules with an intrinsic graphene and a tetracyanoethylene (TCNE) modified graphene surface. The strength of the interactions is investigated by the adsorption energies (Eads) of the molecules on the graphene surface and the changes of the electronic structures (especially by HOMO/LUMO energy gap (Eg)) of graphene. The analysis of Eads shows that the interaction of both CO2 and CH4 with TCNE modified graphene is more favorable. It is assumed that a TCNE molecule can affect the interactions of the molecules with the graphene sheet by reducing the charge accumulation over the graphene surface. However, despite the increase in the strength of interactions, the changes in the electronic properties of both intrinsic and modified graphene is not high enough to consider them as a potential CO2 or CH4 gas detector. However, the considerable amount of Eads in TCNE modified graphene might be a guide to the design of graphene-based adsorbents of CO2 and CH4 molecules.