Enhancing photocatalytic performance of Fe3O4 nanoparticles and Fe3O4@ZnO nanocomposites

Abstract

In this work, Fe₃O₄ nanoparticles and Fe₃O₄@ZnO nanocomposites were prepared by co-precipitation and reflux techniques, respectively. Structural, magnetic, and photocatalytic properties were studied. The crystalline structure and morphology were confirmed by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) analyses. Fe₃O₄ had a cubic spinel structure with a crystal size of 37.5 nm. Fourier transform infrared spectroscopy (FTIR) showed the characteristic peaks corresponding to Fe–O, ZnO, and surface hydroxyl group, confirming that Fe₃O₄ and ZnO exist in nanocomposites. X-ray photoelectron spectroscopy (XPS) analysis confirmed Fe, Zn, and O elements as its surface composition. The vibrating sample magnetometer (VSM) confirmed that the magnetic properties of Fe₃O₄ nanoparticles exhibited superparamagnetism with saturation magnetization of 72 emu/g, whereas it was relatively lower (1.4 emu/g) for Fe₃O₄@ZnO due to the coating of ZnO. The nanocomposites showed the best photocatalytic activity, degrading 77% methylene blue dye in 20 min under natural sunlight, compared with 15% for Fe₃O₄ alone. These findings suggest that the Fe₃O₄@ZnO nanocomposite is a promising candidate for environmental applications, particularly in wastewater treatment.