First-principles Studies of Formaldehyde Molecule Adsorption on Graphene Modified with Vacancy, -OH, -CHO and -COOH Group

Density functional theory (DFT) based ab-initio calculations were used to study the adsorption of CH2O molecule on the intrinsic and vacancy, -OH, -CHO or -COOH group modified graphene. The result indicated that in the optimized structural models of modified graphene, the C-C bond length around the vacancy, -OH, -CHO or -COOH group were compressed or stretched; The CH2O molecule weakly binds to the intrinsic graphene with the binding energy -0.228eV. The binding energy between CH2O and -COOH or -OH group modified graphene were -0.538eV and -0.474eV, which indicates that -COOH and -OH group modified graphene is most suitable for CH2O adsorption; Moreover, the isosurface of the total electron density and the electron density difference between the modified graphene and CH2O molecule were calculated, which illustrated the electron changes and distributions.