Sustainable water treatment: Synthesis and characterization of g-C3N5/NiCo2S4 heterojunction nanocomposite for efficient visible light-induced degradation of highly hazardous organic pollutants

Abstract

Recent modernization has fostered economic growth and altered lifestyles, but has also increased environmental pollution, particularly water contamination. In addressing this challenge, photocatalysis utilizing various photocatalysts, particularly graphitic carbon nitride (g-C₃N₄), has gained significant attention. Building on the success of g-C₃N₄, g-C₃N₅ has emerged as a promising photocatalyst with enhanced properties. In this study, a g-C₃N₅/NiCo₂S₄ nanocomposite was synthesized by varying the concentrations of g-C₃N₅ and NiCo₂S₄. The structural characteristics and their variations were analysed using XRD and FT-IR analyses. The chemical coordination and optical properties were investigated by XPS and UV–Vis spectroscopy, respectively. Pristine g-C₃N₅ exhibits an agglomerated sheet-like structure, whereas NiCo₂S₄ has a bulk, plate-like morphology. In the nanocomposites, the NiCo₂S₄ plate-like structures are uniformly distributed on the surface of g-C₃N₅ sheets, as observed in SEM and HR-TEM, and EDAX analysis confirms the presence of all elements in the composite. The photocatalytic degradation efficiency of the nanocomposites was evaluated using Brilliant Green (BG) dye and Congo Red (CR) dye under visible light irradiation and the results were compared with pristine materials. The degradation efficiency improved with increasing g-C₃N₅ loading, achieving 94.37 % degradation of BG dye within 100 min and 88.83 % degradation of CR dye within 180 min. The nanocomposite showed excellent stability over five cycles, making it a viable and cost-effective candidate with good efficiency. Thus, this nanocomposite holds significant promise for the sustainable degradation of toxic organic pollutants, offering a potential solution in future wastewater treatment.