Synthesis of Fe₃O₄/SiO₂/CeO₂ Core–Shell Magnetic and Their Application as Photocatalyst

The Fe₃O₄/SiO₂/CeO₂ core–shell magnetic has been successfully synthesized by three steps of hydrothermal, sonochemical and homogeneous precipitation by coating CeO₂ nanoparticles onto Fe₃O₄/SiO₂ magnetic core. The prepared samples were characterized by X-ray diffraction (XRD), Field-emission scanning electron microscopy (FESEM) connected with energy dispersive X-ray analysis system (EDS), high resolution transmission electron microscopy (HRTEM), Nitrogen adsorption–desorption analyses (BET), and vibrating sample magnetometer (VSM). The photocatalytic activities for Fe₃O₄/SiO₂/CeO₂ core–shell magnetic under UV and visible lights were measured by determining the degradation rate of formic and oxalic acid in spiral reactor for 120 min. The amounts of CO₂ generated during the process were compared between the magnetic catalyst and bare CeO₂. After the finished photocatalytic degradation, the magnetic catalyst was recovered by external magnetic field at the end of each experiment. The results showed that the photocatalytic activity of Fe₃O₄/SiO₂/CeO₂ core–shell magnetic had higher than that of bare CeO₂ and was found to be constant for three cycles of the recycled use.