Selective Proximate Antarafacial Distribution of Oxidized Functional Groups on Graphene Oxide

Determining the precise chemical structure of graphene oxide (GO) is essential for studying its relevant properties. However, the distribution of oxidized functional groups on GO still lacks sufficient atomic-scale studies. Here, theoretical calculations based on density functional theory have been performed to explore thermodynamic distribution of hydroxyls and epoxy groups on GO. There are three key factors that significantly affect the structural stability: electron distribution, steric hindrance, and hydrogen-bond enhancement, which lead hydroxyls and epoxy groups to be distributed in close proximity of each other on opposite sides of GO. Therefore, the selective proximate antarafacial distribution of oxidized functional groups on GO is proposed, and island-like oxidized regions are assumed to be more favorable to form on the realistic structures of GO. This selective proximate antarafacial distribution pattern helps to explain the origin and evolution of GO surfaces and promotes to understand the microscopic surface chemistry of two-dimensional single-layer structures.