Simple and cost-effective synthesis of graphene by electrochemical exfoliation of graphite rods

We report a simple and efficient approach for graphene production, by electrochemical exfoliation of graphite rods, in acidic solutions. The applied bias and electrolyte concentration were optimized. The X-ray powder diffraction (XRD) patterns of nanosheets reveal the decreasing, or even the disappearance, of the graphene oxide peak by reducing the electrochemical exfoliation bias from +6 to +2.5 V. Thus, graphene with different oxidation degrees can be obtained by controlling the applied bias. An optimal graphene sample was prepared in a mixture of H2SO4 : HNO3 (3 : 1 ratio; 1 M each) at a bias of +3 V. The interlayer spacing, crystallite size and the average number of layers were determined by XRD. The structural and morphological characteristics of the prepared samples were also investigated by Raman Spectroscopy, FTIR Spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM).