Investigation of Evolution in the Synthesis of Graphene Oxide and Reduced Graphene Oxide

Hummer’s method, in which potassium permanganate (KMnO4) acts as the oxidant and concentrated sulfuric acid (H2SO4) serves as the intercalator is commonly used to prepare Graphene Oxide (GO). The amount of the intercalator, oxidant, and graphite are important factors that affect the properties and structure of graphene oxide. In this work, a detailed investigation is carried out to optimize the mechanism of Hummer’s method in order to get the maximum yield of GO and reduced graphene oxide (rGO). XRD, SEM, TEM, FT-IR, TGA, Raman spectroscopy, and UV-Visible spectroscopy are used for characterization. XRD results of optimized samples (Opt-3-GO and Opt-3-rGO) clearly showed that the value of interlayer spacing is increased due to increasing the amount of oxidant and intercalator. SEM and TEM results revealed that the Opt-3-rGO was highly wrinkled nanosheets as compared to the Opt-3-GO. The FT-IR results showed that the double amount of oxidant and intercalator had an effect on the functional groups in the structure of Opt-3-GO and Opt-3-rGO. TGA results indicated that Opt-3-rGO has higher thermal stability as compared to Opt-3-GO due to the lower defect density. The ratio of intensities of D and G bands (ID/IG) increased for Opt-3-rGO as compared to Opt-3-GO. UV-Vis spectra of Opt-3-GO showed a maximum absorption peak at 237 nm attributable to π-π* transition of the atomic C-C bonds. The prepared samples have their use in different applications such as electrode materials for batteries, capacitors, and solar cells.