Phosphotungstic acid supported on magnetic core-shell nanoparticles with high photocatalytic activity

Fe3O4@SiO2@HPW (12-tungstophosphoric acid) nanoparticles have been successfully obtained by a simple solvothermal and impregnation process. The as-obtained products were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), fourier transform infrared spectrum (FT-IR), inductively coupled plasma (ICP) and MPM5-XL-5 superconducting quantum interference device (SQUID). The results revealed that the heteropolyacids were successfully grown on the Fe3O4@SiO2 nanoparticles. The photocatalytic studies suggested that the Fe3O4@SiO2@HPW nanoparticles show excellent photocatalytic efficiency for the degradation of Rhodamine B (RB) under UV light irradiation. More importantly, the obtained nanoparticles (Fe3O4@SiO2@HPW) could be effectively separated for reuse by simply applying an external magnetic field. Furthermore, the synthesized nanoparticles could keep their efficiency till four cycles.