Synthesis of reduced graphene oxide and a study on its electrochemical performance for supercapacitor applications

Abstract

Reduced Graphene Oxide (rGO) is similar to that of pristine graphene in the way that it has excellent mechanical, optoelectronic and conductive properties. Hence it is considered to be the alternative for graphene in many applications. Graphene Oxide (GO) can be produced in number of methods and reduced in number of ways. In this work, GO was synthesized by the Hummers method and it was reduced chemically by hydrazine hydrate. From X-Ray Diffraction (XRD) analysis, diffraction occurred at an angle of 25° and 12° implied the formation of GO and rGO. Further from Raman analysis, the formation of rGO was confirmed by the appearance of the D and G band. Functional groups attached to rGO layers were studied by Fourier Transform Infra Red (FTIR) spectroscopy. From UltraViolet–Visible (UV–Vis) spectroscopy, the bandgap was calculated as 4.1 eV and 2.1 eV for GO and rGO. The surface morphology of the synthesized compound was analysed by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) techniques. The electrochemical performance was studied by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and Galvanostatic Charge and Discharge (GCD) analysis using 1 M Potassium Hydroxide solution as electrolyte. The quasi-rectangular shaped CV graph indicates the electrostatic double layer mechanism. Specific capacitance was 140 F g−1 at 5 A g−1 calculated in three electrode set up. From EIS analysis, the associated resistance of electrode with electrolyte solution was found.