Synthesis of Fe3O4/ZrO2/CuO magnetic nanohybrids and their applications in reducing chromium(vi) and degrading methylene blue under sunlight

Abstract

In the field of water treatment, zirconium dioxide (ZrO₂) is extensively used as a high-performance photocatalyst. Numerous studies have focused on improving the performance of ZrO₂ photocatalysts by introducing metal oxides during synthesis. In this study, Fe₃O₄/ZrO₂/CuO magnetic nanocomposites (NCs) were prepared and analysed using FT-IR (Fourier transform infrared) spectroscopy, UV-DRS (ultraviolet-visible diffuse reflectance spectroscopy), PL (photoluminescence), XRD (X-ray diffraction), FE-SEM (field emission scanning electron microscopy), EDS (energy dispersive spectroscopy), TEM (transmission electron microscopy), ICP (inductively coupled plasma) spectroscopy, N₂ sorption analysis, VSM (vibrating sample magnetometry), TOC (total organic carbon) analysis, and XPS (X-ray photoelectron spectroscopy). The photocatalytic activity of the magnetic Fe₃O₄/ZrO₂/CuO NC was assessed in the photodegradation of methylene blue (MB) and photoreduction of chromium(VI) under sunlight irradiation. The catalyst showed high performance in MB degradation and Cr(VI) reduction (>97% and >90%, respectively). In the synthesized NCs, spherical crystalline structures with an average size of 10 nm were observed. According to the results, the band gaps of Fe₃O₄/ZrO₂ and Fe₃O₄/ZrO₂/CuO were 1.95 and 1.92 eV, respectively. PL results demonstrated that the addition of CuO to Fe₃O₄/ZrO₂ enhanced the photocatalytic ability of Fe₃O₄/ZrO₂/CuO by reducing the rate of electron/hole recombination.