Synthesis of Fe3O4@SiO2@Ce0.5Mn0.5O2 core-shell-shell magnetic submicrospheres as photocatalyst for methyl orange degradation

Core-shell-shell composite (Fe₃O₄@SiO₂@Ce_0.5Mn_0.5O₂) submicrospheres were successfully synthesised by homogeneous precipitation of Ce and Mn on Fe₃O₄@SiO₂ spheres, which were prepared by a modified sol-gel method with the presence of Fe₃O₄ particles. The synthesised multilayer-structured nanocomposites were characterised by X-ray diffraction, Fourier transform infrared spectroscopy, a transmission electron microscope and a vibrating sample magnetometer. The results show that the magnetic Fe₃O₄ cores were well wrapped by the coating layer of SiO₂ with a thickness of 20 nm in the amorphous phase, and the Ce_0.5Mn_0.5O₂ nanoparticles with a diameter of about 20 nm were attached on the SiO₂ shell. The magnetic measurements indicated that the Fe₃O₄@SiO₂@Ce_0.5Mn_0.5O₂ submicrospheres had a superparamagnetism property with the saturation magnetisation of 32.5 eum g^-1. At the same time, the composites demonstrated a high photocatalytic activity for methyl orange (MO) degradation with efficiency up to 94.5% under UV irradiation within 1 h. Moreover, the submicrospheres were found to be stable under repeated applications of up to five successive cycles with a nearly constant photocatalytic activity. It is expected that the catalyst could be used for trace pollutants (MO) removal from water and recycled because of its superparamagnetism properties and high photocatalytic activity.