Bio-fabrication of Ni doped ZnO nanoparticles using Annona Muricata leaf extract and investigations of their antimicrobial, antioxidant and photocatalytic activities

The present work aims to investigate the structural, optical, antimicrobial, antioxidant and photocatalytic activities of Zn1−xNixO (x = 0, 0.03, 0.05 & 0.07) nanoparticles prepared by the green method using Annona Muricata leaf extract. The synthesised nanoparticles were analysed by XRD, FTIR, XPS, HRTEM- SAED, SEM- EDX and UV-Visible spectroscopy. The XRD pattern confirms Ni has been successfully incorporated into the hexagonal wurtzite structure of ZnO. XPS results demonstrate the binding energies of ZnO and Ni. The presence of Zn-O vibrational modes was identified by FTIR spectra. The morphology of prepared samples was investigated through SEM and TEM analysis. The presence of Zn, O and Ni elements in EDX spectra indicates the purity of the sample. The optical bandgap energy of ZnO nanoparticles decreases with an increase in Ni concentration. Antimicrobial activity of nanoparticles were carried out against s.aureus, B.subtilis and P.aeruginosa bacterial strains as well as the fungal strain of A.niger and C.albicans. ZnO nanoparticles have significant antioxidant activity against DPPH free radicals. Under solar irradiation, Zn0.93Ni0.07O nanoparticles exhibit excellent photocatalytic degradation against malachite green (98.4 %) and methylene blue (94.9 %) dye solutions. Finally, these findings suggest an effective utilization of phytochemicals present in the A.muricata leaf extract as a suitable source for biosynthesis of pure and Ni-doped ZnO nanoparticles utilised for biomedical and industrial waste water treatment applications.