Harnessing the power of S/N-doped NiO nanoparticles through bandgap tuning to achieve enhanced photocatalytic and antibacterial performances
Tariku Tamesgen, Michael Asfaw Ameya, Getu Sisay, Lu Yuanqi, Zhu Kai, Tamene Tadesse Beyene
Abstract
Nickel oxide (NiO) is a promising photocatalyst owing to its stability, cost-effectiveness, and eco-friendliness. However, its wide band gap and rapid electron-hole recombination limit its effectiveness under visible light. In this study, we introduce a novel approach by co-doping NiO nanoparticles with sulfur and nitrogen (S/N-NiO-NPs) to overcome these limitations. Using a co-precipitation method, we synthesized and thoroughly characterized the materials, confirming successful doping and significant modifications in their structural and optical properties. Notably, S/N co-doping reduced the band gap from 3.75 to 2.50 eV, enhanced charge separation, and improved visible-light absorption. Under optimal conditions (pH 10), only 40 mg of S/N-NiO-NPs achieved 98.9% degradation of methylene blue dye within 60 min of sunlight exposure; far surpassing the performance of pure NiO. The reusability of the catalyst was also tested, and the degradation efficiency was maintained at approximately 89.92% after three consecutive cycles. Furthermore, the doped nanoparticles exhibited enhanced antibacterial activity, with inhibition zones of 13-17 mm against common pathogens, compared to 5-10 mm for pure NiO. These findings demonstrate that S/N co-doping effectively transforms NiO into a highly efficient, multifunctional material with significant potential for environmental remediation and biomedical applications, marking a notable advancement in photocatalyst design.