Preparation and characterization of Fe3O4/SiO2/Bi2MoO6 composite as magnetically separable photocatalyst

• Fe3O4/SiO2/Bi2MoO6 composite was prepared by a hydrothermal method.
• The composite has an enhanced visible absorption compared with pure Bi2MoO6.
• The magnetic photocatalyst displayed excellent stability and reusability.
• O2− and OH play a major role during the photocatalytic process.

In this paper, Fe3O4/SiO2/Bi2MoO6 microspheres were prepared by a facile hydrothermal method. The scanning electron microscope (SEM) results revealed that flower-like three dimensional (3D) Bi2MoO6 microspheres were decorated with Fe3O4/SiO2 magnetic nanoparticles. The UV–vis diffuse reflection spectra showed extended absorption within the visible light range compared with pure Bi2MoO6. We evaluated the photocatalytic activities of Fe3O4/SiO2/Bi2MoO6 microspheres on the degradation of Rhodamine B (RhB) under visible light irradiation and found that the obtained composite exhibited higher photocatalytic activity than pure Bi2MoO6 and P25. Moreover, the Fe3O4/SiO2/Bi2MoO6 composite also displayed excellent stability and their photocatalytic activity decreased slightly after reusing 5 cycles. Meanwhile, the composite could be easily separated by applying an external magnetic field. The trapping experiment results suggest that superoxide radical species O2− and hydroxyl radicals OH play a major role in Fe3O4/SiO2/Bi2MoO6 system under visible light irradiation. The combination of flower-like three dimensional (3D) Bi2MoO6 microspheres and Fe3O4/SiO2 magnetic nanospheres provides a useful strategy for designing multifunctional nanostructure materials with enhanced photocatalytic activities in the potential applications of water purification.

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