Construction of g-C3N4 anchored Cu-ZnS hybrid nanostructures for sustainable energy storage and environmental remediation

The development of multifunctional materials is essential due to the increasing demand for efficient energy storage and effluent remediation. In this study, a hybrid nanostructure comprising graphitic carbon nitride (g-C₃N₄) and Cu–ZnS was synthesized to function as a dual-purpose material for photocatalytic degradation and supercapacitor applications. The formation of a mixed-phase Cu–ZnS/g-C₃N₄ composite with both cubic and hexagonal ZnS structures was confirmed by powder X-ray diffraction (XRD). The uniform dispersion of Cu–ZnS nanoparticles over g-C₃N₄ sheets was demonstrated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses. BET analysis indicated a 1.6-fold increase in surface area (148.16 m²/g) for CuZnS-GCN25 compared to bare CuZnS. Electrochemical evaluation showed that CuZnS-GCN25 delivered a high specific capacitance of 275 F g⁻¹ at 1 A g⁻¹, excellent cycling stability (92.5% after 10,000 cycles) and 70% capacitance retention at 20 A g⁻¹ in a two-electrode setup. In photocatalytic testing, CuZnS-GCN25 achieved 92.4% degradation of amoxicillin (AMX) within 60 min under visible light, following pseudo-first-order kinetics with a rate constant of 0.029 min⁻¹. These results highlight the potential of CuZnS-GCN25 as a high-performance, eco-friendly material for integrated energy and environmental remediation systems.