Facile Co-precipitation Synthesis of Zn-Doped NiO Nanoparticles for Enhanced Photocatalytic Degradation of Organic Dyes

Zinc-doped nickel oxide (Zn: NiO) nanoparticles with different concentrations of Zn were synthesized effectively through a simple co-precipitation technique. X-ray diffraction analysis of the structural properties confirmed the development of a single-phase cubic NiO lattice, with minor shifts in peaks indicating the successful integration of Zn²⁺ ions into the NiO matrix. Morphological studies using scanning and transmission electron microscopy revealed almost spherical nanoparticles with reduced agglomeration due to Zn doping. Optical investigations revealed a distinct reduction in the band gap compared to pure NiO, which is attributed to defect-induced energy levels and improved charge carrier separation. The photocatalytic activity of the Zn: NiO nanoparticles was assessed by measuring the degradation of malachite green dye under UV-visible light exposure. The Zn-doped samples exhibited significantly enhanced photocatalytic performance compared to undoped NiO, achieving higher degradation efficiency and faster reaction rates. The enhanced photocatalytic activity is attributed to an increase in surface active sites, reduced electron-hole recombination, and improved light absorption caused by Zn doping. These findings indicate that Zn-doped NiO nanoparticles produced by the co-precipitation method are promising candidates for photocatalytic applications in wastewater treatment.