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 ruffle (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 ruffle phase, respectively). The as-prepared nanocomposite samples exhibit superparamagnetic properties at room temperature with high saturation magnetization (M-s) 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.