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.
