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 photoeleclron 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 shouted 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 center dot OH and center dot O-2(-) 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 jive consecutive degradation cycles. (C) 2017 American Institute of Chemical Engineers