Synthesis and study of physicochemical properties of Fe₃O₄@ZnFe₂O₄ core/shell nanoparticles

In this work, Fe₃O₄@ZnFe₂O₄ core/shell nanoparticles were obtained by depositing ZnO by the wet chemistry method on the surface of Fe₃O₄ nanoparticles seeds obtained by the chemical bath deposition method. Fe₃O₄ and Fe₃O₄@ZnFe₂O₄ were characterized by Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectrometry, Transmission Electron Microscopy, X-ray Diffraction, Ultraviolet–Visible Spectroscopy, Diffuse Reflectance, and Fourier Transformed Infrared Spectroscopy (FTIR). The Fe₃O₄@ZnFe₂O₄ nanoparticles formed an urchin-like spheres morphology (corresponding to Fe₃O₄) with a homogeneous shell of ZnFe₂O₄. XRD analysis showed a magnetite crystal structure for Fe₃O₄ and a franklinite (ZnFe₂O₄) crystal structure for the shell. Fe₃O₄@ZnFe₂O₄ showed higher crystallinity when applying a heat treatment, showing a crystal size of 9.12 nm with heat treatment and 9.43 nm without heat treatment. The diffuse reflectance results suggested an indirect band gap of 1.85 eV for Fe₃O₄ and two indirect band gaps of 1.85 eV and 2.54 eV for Fe₃O₄@ZnFe₂O₄. The FTIR results showed the effect of heat treatment on Fe₃O₄@ZnFe₂O₄ core/shell nanoparticles. A simple method was used for the synthesis of Fe₃O₄@ZnFe₂O₄.