Advanced engineering of smart nanomaterials: ZnWO₄/CoWO₄/g-C₃N₄ heterojunction photocatalysts for environmental and biomedical application

The advanced engineering of smart nanomaterials has emerged as a promising approach to address critical challenges in environmental and medicinal applications. In this study, we present the design and synthesized multivariate ZnWO₄/CoWO₄/g-C₃N₄ nanocomposites using a straightforward simple one-step wet impregnation process, significantly boosting their performance in various photocatalytic and antibacterial applications. The synergistic combination of ZnWO₄ and CoWO₄ nanoparticles were anchored onto multiple active sites on the surface of g-C₃N₄ nanosheets. When compared to pristine g-C₃N₄ nanosheet, ZnWO₄, CoWO₄, and the binary ZnWO₄/CoWO₄ nanocomposite, the ternary ZnWO₄/CoWO₄/g-C₃N₄ nanocomposite exhibits superior antibacterial and photodegradation activity of methylene blue (MB) dye under visible light irradiation. The optimal ternary ZnWO₄/CoWO₄/g-C₃N₄ nanocomposite demonstrates a degradation efficiency of 94.6 % after 120 min, additionally, the common bacterial pathogens, including Staphylococcus aureus (+Ve) and Escherichia coli (-Ve), were also tested. From mechanistic insights, the charge migration pathway, radical quenching study, stability and reusability analysis were observed in ternary ZnWO₄/CoWO₄/g-C₃N₄ nanocomposites. The significant participation of hydroxyl (*OH^-) radicals during the photocatalytic MB degradation was verified by reactive oxygen species trapping experiments. Furthermore, the antibacterial activity was observed with the individual extracts and when they were used in lower to higher concentrations with ineffective antibiotics. The enhanced photocatalytic degradation and antibacterial properties of ternary ZnWO₄/CoWO₄/g-C₃N₄ nanocomposites can be attributed to the synergistic effects of strong charge migration and remarkable stability properties. Further research has shown that the synergistic role of ZnWO₄/CoWO₄/g-C₃N₄ nanocomposites significantly enhances their environmental and biological properties.