LAUSR

Abstract Nanocomposites based on nickel oxide and zinc oxide (NiO–ZnO) semiconductors have gained pronounced attention in several areas rather than in antibacterial applications. Present investigation is devoted to synthesis NiO–ZnO nanocomposites with different concentrations (0.03, 0.06, 0.09 and 0.12 M) of Ni2+ ions by a facile chemical co-precipitation method. UV-Visible spectral analysis revealed that absorption band edge of pristine ZnO nanoparticles is red shifted to visible region due to incorporation of Ni2+ ions in Zn2+ sites of ZnO lattice. Band gap energy of NiO–ZnO nanocomposites is decreased owing to induction of strain in crystal lattice. Photoluminescence results disclosed that high concentrations of Ni2+ ions in NiO–ZnO nanocomposites improve distortion centers and lattice surface defects in ZnO and as a consequence that minimizes defect related emissions. X-ray diffraction patterns exhibited diffraction peaks corresponding to face-centered cubic NiO and hexagonal wurtzite structured ZnO. Energy dispersive X-ray spectroscopy analysis indicated presence of Ni, Zn and O elements in the nanocomposites and confirmed their purity. Field emission scanning and high resolution transmission electron microscopy images signified composite morphology of NiO–ZnO nanocomposites containing randomly oriented nanorods decorated with nanoparticles. Enhanced bactericidal activity of NiO–ZnO nanocomposites over pristine ZnO nanoparticles against selected bacterial species can be ascribed to increase in surface area, decrease in crystalline size and higher reactive oxygen species generation after modification by Ni2+ ions. Based on this pronounced bactericidal activity, it is concluded that NiO–ZnO nanocomposites can be potentially employed as bactericidal agents against pathogenic bacterial species.