An analysis of the effects of s/n co-doping nio nanoparti Cles on its energy band gap, photocatalytic activity, And antibacterial properties

Abstract

Nickel oxide has garnered significant interest as a photo catalyst due to its high efficiency, photochemical stability, low cost, and eco-friendliness. However, its large band gap and rapid electron-hole recombination limit its performance in the visible light region. In this study, pure NiO nanoparticles (NiO-NPs) and S/N co-doped NiO nanocomposites (S/N-NiO-NCs) were synthesized via the co-precipitation method to enhance their photocatalytic and antibac terial properties. Doping with 4% sulfur and 6% nitrogen reduced the band gap from 3.75 eV to 2.74 eV and decreased the crystalline size from 20.49 nm to 17.89 nm. Under optimal con ditions (pH 10), 40 mg of S/N-NiO-NCs achieved 98.9% degradation of 5ppm methylene blue dye within 60 minutes of sunlight exposure, outperforming pure NiO-NPs. Antibacterial activity, assessed through inhibition zone measurements, showed significant improvement: NiO-NPs exhibited zones of 5–10 mm, while S/N-NiO-NCs achieved 13–17 mm against Ba cillus cereus, Escherichia coli, Salmonella typhi, and Staphylococcus aureus. UV-Vis, FT-IR, XRD, and SEM analyses confirmed successful doping and structural modifications, contrib uting to improved charge separation and extended light absorption. These results highlight the potential of S/N co-doping in enhancing the multifunctionality of NiO.