Improved synthesis of graphene oxide with controlled oxidation degree by using different dihydrogen phosphate as intercalators

The controllable oxidation degree of graphene oxide (GO) by improving Hummers method are currently being addressed. In this work, Improved Hummers method with appropriate optimization was used to yield GO. The oxidation degrees of GO were controlled via changing different phosphate intercalators (KH2PO4, NaH2PO4, LiH2PO4 and H3PO4) in pre-oxidation stage. After oxidized exfoliation and purification, GO samples were analyzed by FTIR, UV-Vis, TGA, Raman spectra, XPS, XRD, SEM and TEM. The results indicated the efficiency of intercalation and oxidation decreased sequentially in intercalator KH2PO4, H3PO4, NaH2PO4 and LiH2PO4. Take GO from KH2PO4 for example, it showed the high-quality oxidation due to 53.18% oxidized carbon and interlayer spacing at 9.87 angstrom. These data provided the possibility to control properties through oxidation degree and broaden applications of graphene oxide applications.