Structural and electrochemical studies of modified GO and rGO for sensing and energy applications

This study investigates the synthesis and characterization of graphene oxide (GO) and its reduced form, reduced graphene oxide (rGO), focusing on their structural, physicochemical and electrochemical properties. Graphene oxide was synthesized from graphite flakes using the modified Hummer’s method, and hydrothermal reduction with ascorbic acid, which was employed to convert GO into rGO, forming a two-dimensional structure with a high surface area. The structural transformations were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM), which revealed a significant reduction in interlayer spacing and restoration of the [Formula: see text] hybridized carbon network in rGO, confirming the successful reduction of GO. Chemical modifications were characterized through Fourier transform infrared (FTIR) spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy and X-ray photoelectron spectroscopy (XPS). These techniques demonstrated a marked decrease in oxygen-containing functional groups in rGO, indicating effective reduction and restoration of graphitic structure. Electrochemical studies using cyclic voltammetry demonstrated that rGO-modified carbon paste electrodes (rGO/MCPE) offer superior sensitivity and enhanced electron transfer efficiency. The effects of scan rate, concentration and pH were also evaluated, underscoring its potential for high-sensitivity detection applications. These findings highlight the potential applications of GO and rGO in electrochemical sensors, particularly for detecting biomolecules like serotonin, as well as in energy storage devices such as supercapacitors and batteries, where their high surface area and conductivity offer significant advantages.