Evaluating the Effect of Graphite Source and Operating Conditions on the Synthesis of Graphene Oxide

Abstract

In this research graphene oxide was synthesized by two methods. These methods were achieved by changing the improved Hummers' and modified Hummers' methods. Structure of graphene oxide was characterized by scanning electron microscopy (SEM) images, X-ray diffraction (XRD) patterns, Raman spectroscopy and Fourier transform infrared (FTIR) spectra. According to SEM image, the thickness of graphene oxide sheets prepared by improved Hummers' method is about 66 nm. In improved Hummers' method excluding NaNO3 from reacting gel and performing reaction in a 9:1 volume ratio of concentrated H2SO4/H3PO4 mixture improved the oxidation process by elimination of toxic gases, finally the prepared GO contains well-oxidized carbon materials. XRD results implied more oxidation for synthesized GO by improved Hummers' based method. Importance of graphite source was shown in synthesis of pure GO. Two sources of graphite supplied by Daejung and Fluka Companies were used to synthesis GO in improved Hummers' method. According to SEM images and XRD patterns, the graphite source prepared by Fluka Co. was more efficient towards production of pure GO than other graphite source. The results also indicated that temperature and mixing condition are two important factors for synthesis of GO.