Green synthesis and characterizations of citric acid-functionalized graphene oxide via electrochemical method: In situ surface modification using citric acid

Abstract

Surface modification by using citric acid (CA) in the graphene is a process to modify the physicochemical properties of graphene oxide. The strategy that has been proposed depends upon the electrochemical exfoliation of reduced graphene oxide (rGO), and simultaneously, the surface modification of rGO with CA carried out in accordance with the green technique. The synthesis of graphene oxide that has been doped with CA was accomplished via an electrochemical process in an aqueous medium containing fresh lime juice and sulphuric acid (electrolyte heating aided method at [Formula: see text]C) as an electrolyte. The electrolyte has been prepared using CA & H2SO4 (sulphuric acid), and both were mixed in a proportion of 1:2. In order to dilute the H2SO4 and perform the sonication, the water that has been pasteurized (according to the USP standards for irrigation) was used. The crystallite size, structural disorder, structure and surface morphology of the CA-doped graphene oxide were identified through X-ray diffraction (XRD) analysis, Raman spectroscopy, Field emission scanning electron microscope (FE-SEM). The presence of oxygen-containing functional group and adsorption has been analyzed using Fourier transform infrared (FTIR), and UV–Vis spectroscopy. The thermal stability of the CA-doped, and without CA-doped thermally reduced graphene oxide (TRGO) has been analyzed via thermogravimetric analysis (TGA). A green, simple, and environmentally friendly method has been demonstrated for the synthesis of CA-doped TRGO by electrochemical synthesis method by using natural dopant.