Fabrication of rGO-based g-C3N4/NiO nanocomposites with enhanced electrochemical energy storage capability

Abstract

Demand for energy storage devices has been increasing due to the rising energy consumption by humans. There is a need to establish clean, environmentally friendly energy devices that are efficient and can store energy effectively. The current study aims to develop reduced graphene oxide (rGO) through the chemical reduction of graphene oxide, g-C₃N₄ (graphitic carbon nitride) by thermal polymerization, nickel oxide (NiO) through the co-precipitation method and lastly ternary nanocomposites of g-C₃N₄–NiO/rGO (GNR 1, GNR 2 and GNR 3) with different ratios of rGO. The synthesized nanostructures were characterized for phase purity and crystallinity using X-ray diffraction (XRD). The XRD results revealed that the nanocomposite GR3 has a crystallite size of 15.24 nm. The presence of different functional groups was confirmed by Fourier transform infrared (FTIR) spectroscopy. The energy band gap was calculated using UV-vis spectroscopy. The pure and well-defined morphology of the materials was confirmed by scanning electron microscopy (SEM). The ternary nanocomposites of g-C₃N₄–NiO/rGO (GNR 1, GNR 2 and GNR 3) were investigated for supercapacitor applications. The electrochemical analysis of nanocomposites was performed by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. An excellent specific capacitance of 1345.71 F g⁻¹ was observed for the nanocomposite GNR 3 at a current density of 1 A g⁻¹. So, the synthesized nanocomposite has the potential to be used in energy storage devices and supercapacitor applications.