Thermal exfoliation of electrochemically obtained graphitic materials

Abstract The present work is devoted to the electrochemical formation and thermal exfoliation of graphite oxide (GO) and reduced graphite oxide (rGO). The main attention was paid on the correlation between cycling processes of GO formation followed by its electrochemical reduction and the stage of their exfoliation. For this purpose a natural graphite was overoxidized in 8 M HClO4 to form GO which was further cathodically reduced yielding rGO. Both processes were performed within one electrochemical process in three-electrode cell using a cyclic voltammetry method. To examine the reversibility of the coupled overoxidation of graphitic matrix and its two-stage reduction the above mentioned operations were three times repeated. The acquired results clearly showed that the properties of GO and rGO significantly change with number of performed cycles. The structure of graphite matrix gradually decreases disenabling the efficient intercalation of perchloric acid during renewed process proceeded during the further cycling. Thermal treatment of electrochemically obtained materials leads to their exfoliation thus contributing to significant modification of structure, morphology and chemical composition. The information on GO properties were provided by the determination of specific surface area, X-ray diffraction analysis (XRD), Raman spectroscopy, Fourier-transform infrared spectroscopy analysis (FTIR), transmission electron microscopy (TEM) and scanning electron microscopy observations (SEM).