Phosphotungstic acid encapsulated in MIL‐53(Fe) as efficient visible‐light photocatalyst for rhodamine B degradation

Materials based on phosphotungstic acid (H3PW12O40, HPW) encapsulated in metal organic framework MIL-53(Fe) were prepared by a simple solvothermal method. The as-synthesized samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectra, and UV–vis diffuse reflectance spectroscopy method. The resulting materials were evaluated in the photodecomposition of cationic dye Rhodamine B (RhB) under visible light irradiation. A Light-emitting diodes lamp was used as visible light source. The results showed that the composites exhibited better photocatalytic activities than pure materials. A possible photocatalytic reaction mechanism has been investigated. The formation of active oxygen species such as •OH and • O2−, which are detected during the degradation of RhB, is proposed to be responsible for the degradation of RhB. In addition, the HPW@MIL-53(Fe) photocatalyst exhibited good chemical stability after five consecutive degradation cycles. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1342–1350, 2017