Electrochemical performance enhancement of ZnO/g-C3N4 nanocomposites using urea and thiourea precursors for supercapacitor applications

• We developed ZnO/G-C 3 N 4 composite using urea and thiourea for supercapacitor electrode material. • ZnO/U-G-C 3 N 4 and ZnO/Tu-G-C 3 N 4 exhibited enhanced redox activity. • ZnO/TU-G-C 3 N 4 achieved 415F/g, surpassing ZnO/U-G-C 3 N 4 (408F/g) and pure ZnO (223F/g). Supercapacitors are becoming strong options for energy storage devices. They offer quick charging and discharging, high density, and long-lasting stability over many cycles. This research focuses on the synthesis of graphitic carbon nitride (g-C 3 N 4 ) and sulfur-doped graphitic carbon nitride using urea (U-g-C 3 N 4 ) and thiourea (TU-g-C 3 N 4 ), respectively, along with the fabrication of ZnO/g-C 3 N 4 based nanocomposites for supercapacitor electrode applications. The study aims to enhance electrochemical performance by integrating ZnO with U-g-C 3 N 4 and TU-g-C 3 N 4 as separate nanocomposites, leveraging their synergistic properties to improve energy storage capabilities. The fabricated ZnO/U-g-C 3 N 4 and ZnO/TU-gC 3 N 4 nanocomposites were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV–Vis spectroscopy to analyze their structural, morphological, and optical properties. Furthermore, electrochemical tests, including cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), were conducted to evaluate their electrochemical performance. The results indicated that the ZnO/TU-g-C 3 N 4 nanocomposites achieved an impressive specific capacitance of 415F/g at a 50 mV/s, which is significantly higher than the capacitance values observed for ZnO/U-g-C 3 N 4 (408F/g) and ZnO (223F/g). Furthermore, ZnO/U-g-C 3 N 4 and ZnO/TU-g-C 3 N 4 demonstrated superior electrochemical stability, this indicates improved redox activity and superior charge storage ability. The results underscore the potential of ZnO/U-g-C 3 N 4 and ZnO/TU-g-C 3 N 4 nanocomposites as effective electrode materials for advanced supercapacitor applications.