Synthesis of highly oxidized graphene (HOG) by using HNO3 and KMnO4 as oxidizing agents

Abstract

A fast and efficient route is a key challenge in synthesis of graphene oxide (GO). In the present work, we report the synthesis of highly oxidized graphene (HOG) via 2 step chemical oxidation method by using a mixture of H2SO4 and HNO3 as the intercalating and initial oxidizing agent followed by KMnO4 as the final oxidizing agent. The XRD results of HOG showed peaks at 2θ = 9.7 (d spacing = 9.1 Å) which is the largest ever reported in such a short synthesis time. Raman spectroscopy confirmed the XRD results which proved that HOG is highly oxidized. UV–vis spectra provided evidence of the presence of an ample number of oxygen functionalities, such as hydroxyl, carboxyl, epoxide, and carbonyl on graphene oxide. SEM results exhibited the presence of wrinkles and folds along with a rough surface in HOG. The GO prepared by this method took only 3.5 hrs and is more oxidized compared to the ones prepared by Hummers method.