Authors: N.А. Lvova, О.Yu. Ananina
Affilation: Technological Institute for Superhard and Novel Carbon Materials, Russian Federation
Pages: 379 - 382
Keywords: graphene functionalization, fluorine adsorption
In this paper, we simulated the adsorption of fluorine on the surface of mono- and polycrystalline graphene from F- and FHF- ions associates with water molecules. As model objects, we used graphens without grain boundaries, as well as the ones containing boundaries with different grain misorientation angles θ. We applied the quantum-chemical methods to investigate the interaction of negatively charged FHF- and F- ions with the surface leading to the F- ion adsorption. It was found that the presence of the grain boundary affects the energy characteristics of the FHF- ion dissociative adsorption: the activation energy of fluoride ion adsorption decreases, while the heat of adsorption increases compared to the defect-free graphenes. The presence of water can lead to a significant decrease in the activation energy for the fluorine adsorption from the associates with water molecules. In our opinion, the most probable mechanism of defect-free graphene fluorination in aqueous solution of hydrofluoric acid is F- ions joining from the associates with water molecules. The results can be used to analyze the physical and chemical processes on the graphene surface during fluorination.