β-Cyclodextrin-assisted electrochemical exfoliation of graphite for few-layer graphene synthesis

Abstract

This study demonstrates that the electrochemical intercalation of graphite in the presence of self-aggregates of β-cyclodextrin (SA-βCD) dissolved in 1 mol L⁻¹ HClO₄ yields high-quality few-layer graphene (FLG). SA-βCD acts as a surfactant, facilitating exfoliation under environmentally safer conditions compared to previously reported methods. Additionally, the intercalation potential is significantly reduced compared to other media, thereby preventing the oxidation of the FLG. In the electrochemical experiments, graphite was incorporated into a carbon paste electrode and subjected to cyclic voltammetry, leading to the formation of a colloidal suspension of FLG and SA-βCD. Fourier-transform infrared spectroscopy, X-ray diffraction, ultraviolet-visible spectroscopy, and Raman spectroscopy analyses confirmed that the electrochemical exfoliation assisted by SA-βCD produced FLG without oxygen functional groups or residual SA-βCD. The electrochemical proprieties were consistent with those of graphene derivatives. Scanning electron microscopy and transmission electron microscopy analyses revealed that the FLG had large lateral dimensions ranging from 2 to 10 μm. The graphene sheets were flat and free of wrinkles, with some edges folded back on themselves or scrolled.