Synthesis and Properties of Magnetic-Semiconductor Fe₃O₄/TiO₂ Heterostructure Nanocomposites for Applications in Wastewater Treatment

In this research, a simple method has been presented to synthesize the magnetic - semiconductor Fe₃O₄/TiO₂ heterostructure nanocomposites via three steps: firstly, synthesis of Fe₃O₄ nanoparticles by co-precipitation method; thereafter, formation of Fe₃O₄/TiO₂ composites by sol-gel method; finally, annealing to form Fe₃O₄/TiO₂ anatase (denoted as Fe₃O₄/TiO₂-A) and Fe₃O₄/TiO₂ rutile (denoted as Fe₃O₄/TiO₂-R) heterostructure nanocomposites, respectively. The results of X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy show that the Fe₃O₄/TiO₂-A and Fe₃O₄/TiO₂-R heterostructure nanocomposite samples contain both magnetite (Fe₃O₄) and semiconductor TiO₂ (anatase or rutile phase, respectively). The asprepared nanocomposite samples exhibit superparamagnetic properties at room temperature with high saturation magnetization (MSUBs/SUB) above 19.5 emu/g at the applied magnetic field of 11 kOe. Moreover, the Fe₃O₄/TiO₂-A and Fe₃O₄/TiO₂-R heterostructure nanocomposites with a low band gap energy of 2.89 eV and 2.81 eV, respectively, are promising to enhance the performance of photocatalytic activities in the visible light region for application in wastewater treatment.