Bifunctional application of facile green-silver doped nickel ferrite nanoparticles via-combustion method

Silver-doped nickel ferrite nanoparticles were green symphonized via the combustion-assisted method using Cocos nucifera milk extract as a fuel with the chemical formula Ag_xNi_1-xFe₂O₄, where x = 0.0, 0.2, 0.4, and 0.6, and named as NF, ANF-1, ANF-2, and ANF-3 NPs, respectively. The symphonized nanoparticles were characterised by XRD, FT-IR, SEM with EDS, TEM, PL, and UV–visible spectroscopy. XRD patterns reveal the spinel cubic structure, average crystalline sizes of 24, 27, 35, and 37 nm of NPs, and lattice parameters that increase with an increase in silver dopant. The vibrational stretching frequency of the metal-oxygen bond was observed in the tetrahedral and octahedral lattice, which was confirmed by FT-IR spectra. SEM and HRTEM reveal the nanoflakes-like structure with agglomeration, and EDS validates the elemental composition. The bandgap was determined by UV-visible spectroscopy, which decreases with an increase in the doping of silver. The luminescence spectra show a decrease in peak intensity as the silver dopant is increased. The photocatalytic performance of symphonized nanoparticles was examined against methylene blue dye under visible light illumination. Antibacterial activity of NF and ANF-2 nanoparticles was tested using gram positive Enterococcus faecalis and gram-negative Escherichia coli and X. campestris bacterial strains, where silver-doped nickel ferrite showed superior antibacterial performance compared to nickel ferrite.