Synthesis, Structural and Optical Characterization of Graphene Oxide and Reduced Graphene Oxide

Graphene oxide has a similar layered structure to graphite, but the plane of carbon atoms in graphene oxide is heavily decorated by oxygen-containing groups, which not only expand the inter-layer distance but also make the atomic-thick layers hydrophilic. As a result, these oxidized layers can be exfoliated under moderate ultrasonication. If exfoliated sheets contain only one or few layers of carbon atoms like graphene, these sheets are named graphene oxide (GO). These graphene oxides have important applications in areas related to transparent conductive films, composite materials, solar energy and biomedical applications. Present study deals with synthesis of graphene oxide using modified Hummers method and the same is followed by the exfoliation of graphene oxide in distilled water using the ultrasound frequency from a laboratory ultrasonic bath. Finally, the oxygen functional groups on exfoliated graphene oxide were eliminated by stirring in distilled water at 95 C, as a replacement for highly toxic and dangerously unstable hydrazine. Crystallographic, topographic and morphological analyses of GO and reduced grapheme oxide (rGO) have been studied via powder X-ray diffraction and electron microscopy [Field Emission Scanning Electron Microscope and High Resolution Transmission Electron Microscope], respectively. Optical analysis of GO and rGO have been conceded via energy resolved and time resolved photoluminescence and energy dispersive X-ray spectroscopic studies respectively. Spectroscopic studies confirm the formation of high quality GO and rGO. Fourier transform infrared spectroscopy, UV-Vis absorption spectroscopy, Raman spectroscopy, X ray photoelectron spectroscopy, thermogravometric analysis, have been carried out for detailed quantative and qualititative analysis of GO and rGO. Structural analysis of GO and rGO have been studied using Brunauer-Emmett-Teller Surface area analysis Barrett-Joyner-Halenda pore size and volume analysis technique.