Atomic Structure Control of Graphene Oxide by Cascading Oxidation and Its Efficient Binding to Aromatic Compounds

Graphene oxide (GO) is recognized as an important functional material in its own right, with applications ranging from advanced separation to electronics. Previous research has focused on the development of novel fabrication processes, however, precise control over the atomic structure of GO, critical for determining its properties, remains elusive. A cascading oxidation process, enabling stepwise oxidation for control over two key atomic structures-graphitic and oxidized regions-within GO, is reported. By transitioning the conventional diffusion-controlled kinetics to reaction-controlled ones, this approach uses a very low oxidant-to-graphite ratio (R = 0.5) and yields low-oxidation graphene oxide (LoxGO) comprising 41.8% graphitic regions, 58.2% oxidized regions, with negligible hole defects (<0.1% holes). This unique structure also features significantly larger graphitic domains (≈8.3 nm²) compared to typical GO (≈1.3 nm²), resulting in high adsorption capacity and up to ≈2.1 times higher removal efficiency for aromatic emerging contaminants, including endocrine disruptors and antibiotics. Mechanistic studies reveal that efficient bonding to aromatic molecules is attributed to LoxGO's abundant π-π interaction sites, coupled with its large graphitic areas facilitating size-matching adsorption. These results provide a novel strategy for tailoring GO's atomic structure and offer insights into its molecular interactions to target contaminants, addressing global environmental sustainability.