Microwave-assisted CuO-modified porous ZnO nanosheet for photocatalytic degradation of organic pollutants and antibacterial inactivation

The present study investigated the development of a porous ZnO/CuO photocatalyst for photocatalytic dye degradation and antibacterial inactivation of bacteria. Porous ZnO nanosheets are prepared by calcinating inorganic-organic ZnS(en)_0.5. Further, CuO was integrated on a porous ZnO nanosheet using the microwave (MW)-assisted synthesis technique. Additionally, the effect of CuO at different concentrations on the photocatalytic activity of CuO/ZnO was investigated. Under 1.5 G light illumination, an optimized ZnO/CuO-5 photocatalyst exhibited higher degradation efficiencies of 99.3 %, 98 %, and 99 % for orange II dye, methylene blue (MB), and Eosin-Y respectively. The optimized photocatalyst exhibited inactivation efficiencies of 98 % and 90 % towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria, after 3 h. The enhanced photocatalytic activity was attributable to a porous structure, extended visible light responsiveness, and delayed electron-hole recombination in nanostructured CuO/ZnO photocatalysts. Moreover, radical scavenger tests confirmed that superoxide radicals (•O₂⁻) accompanied most degradation, followed by holes (h⁺) as minor factors. Our work suggests a simple photocatalytic interfacial engineering technique based on porous ZnO/CuO nanostructures to decompose organic chemicals and inactivate microorganisms in wastewater sources.