DFT study of graphene oxide reduction by

Recently, a large interest has arisen for using less active reducers of graphene oxide (GO) that are environmentally friendly. The present work conducted a DFT theoretical study on the reduction process of GO model surfaces, employing zwitterionic dopamine (ZDA) as the reducing agent. Various periodic models representing epoxy and hydroxyl patches on the GO basal plane were proposed. As the number of oxide groups in a patch of epoxies or hydroxyls on the graphene surface increased from 1 to 5, the stability of these systems was observed to increase. The adsorption behavior of ZDA on patches of GO with 5 epoxy groups proved to be non-dissociative, whereas, for patches with 5 hydroxyl groups, the adsorption was fundamentally dissociative, effectively reducing the surface of graphene oxide. The produced H2O molecule during the GO reduction was found to be trapped by ZDA through a hydrogen bond. The analysis of ZDA binding to GO incorporated electrostatic effects and attractive non-covalent contributions resultant from van der Waals interactions.