Dataset of optimized structures of reduced graphene-oxide with metal ions: Role of oxygen functional groups in metal ion adsorption

An interaction between a model system of reduced graphene oxide and a set of the first-row transition metal (TM) ions is investigated at the DFT level of theory. Optimized structures of the reduced graphene oxide with adsorbed TM ions in different spin states are presented. Three adsorption sites of the model system of reduced graphene oxide are considered, namely epoxide (O), hydroxyl (OH), and carboxyl (COOH) functional group. It is found that the energetically most favoured mode of interaction between the studied set of TM ions and the reduced graphene oxide is the adsorption on the OH group. In the case of Cr²⁺, Fe²⁺, Co²⁺, Ni²⁺, and Zn²⁺ ions, such interaction results in the cleavage of C-OH bond, consequently leading to formation of the TM-OH residue above the graphene basal plane. On the other hand, the energetically least favoured interaction between the TM ions and reduced graphene oxide occurs on the edge COOH groups. The optimized structures presented herein may also serve as a basis for reference in future computational studies of graphene oxide-based materials.