Investigation of structural, optical, magnetic properties and antibacterial activity of Ni-doped zinc oxide nanoparticles

Abstract

In this study, pure ZnO and Ni doped ZnO nanoparticles were successfully synthesized by using the wet chemical precipitation method. Pure and Ni doped ZnO nanoparticles samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), UV–visible (UV–Vis) and FTIR spectroscopy. The XRD investigation of pure and Ni-doped ZnO nanoparticles samples reveal and confirm the formation of single phase hexagonal wurtzite structure, without formation of any secondary and other impurity phases. XRD results further reveals the shifting of characteristics peak toward higher 2θ (theta) angle with Ni doping. This shifting of the XRD peaks toward higher angle clearly indicates that Ni ions are effectively incorporated in the ZnO lattice. Surface morphology of pure and Ni doped ZnO nanoparticles samples was performed by using the SEM confirms the formation of spherical nanocrystallites with fine and clear defined boundaries. EDS spectroscopy indicates the substitution of dopant Ni2+ effectively in lattice site of Zn2+ as evident from XRD result also. The carriers i.e. donors confined on the Ni sites were confirmed from the micro Raman spectroscopy. Optical property of Ni-doped samples is confirmed by using the UV–Vis absorption which showed blue shift in absorption edge as compared to undoped ZnO nanoparticles. Undoped and Ni-doped ZnO nanoparticles exhibit considerable changes in the M–H loop, specifically the diamagnetic response changed into ferromagnetic character for Ni doped samples in VSM investigation. The antibacterial activities of the Nickel doped zinc oxide were studied against Gram-negative (Shigella dysenteriae, Vibrio cholerae, and E. coli) via using agar well diffusion technique. Further, these Ni doped nanoparticles were then applied as antibacterial agent to control the microorganisms or bacterial growth. Ni-doping on zinc oxide and exposure of sunlight enhanced the antibacterial activity against bacterial pathogens which isolate at 40–45 μg concentration. Interestingly in this study, most effective antibacterial results were obtained against the water related bacteria such as E. coli and V. cholerae for Ni-doped ZnO NPs.