Multifunctional Core‐Shell NiFe<sub>2</sub>O<sub>4</sub> Shield with TiO<sub>2</sub>/rGO Nanostructures for Biomedical and Environmental Applications
R. Esther Nimshi, J. Judith Vijaya, Basma Al‐Najar, Layla J. Hazeem, M. Bououdina, L. John Kennedy, K. Kombaiah, Stefano Bellucci
Abstract
Multifunctional core@shell nanoparticles have been synthesized in this paper through 3 stages: NiFe 2 O 4 nanoparticles by microwave irradiation using Pedalium murex leaf extract as a fuel, core@shell NiFe 2 O 4 @TiO 2 nanoparticles by sol‐gel, and NiFe 2 O 4 @TiO 2 @rGO by sol‐gel using preprepared reduced graphene oxide obtained by modified Hummer’s method. XRD analysis confirmed the presence of both cubic NiFe 2 O 4 spinel and tetragonal TiO 2 rutile phases, while Raman spectroscopy analysis displays both D and G bands ( I D / I G = 1.04) associated with rGO. Morphological observations by HRTEM reveal a core‐shell nanostructure formed by NiFe 2 O 4 core as confirmed by SAED with subsequent thin layers of TiO 2 and rGO. Magnetic measurements show a ferromagnetic behavior, where the saturation magnetization drops drastically from 45 emu/g for NiFe 2 O 4 to 15 emu/g after TiO 2 and rGO nonmagnetic bilayers coating. The as‐fabricated multifunctional core@shell nanostructures demonstrate tunable self‐heating characteristics: rise of temperature and specific absorption rate in the range of Δ T = 3–10°C and SAR = 3–58 W/g, respectively. This effectiveness is much close to the threshold temperature of hyperthermia (45°C), and the zones of inhibition show the better effective antibacterial activity of NTG against various Gram‐positive and Gram‐negative bacterial strains besides simultaneous good efficient, stable, and removable sonophotocatalyst toward the TC degradation.