Magnetic iron oxide modified MIL-101 composite as an efficient visible-light-driven photocatalyst for methylene blue degradation

In this study, a facile hydrothermal method was used to prepare Fe₃O₄/MIL-101 composite as a photocatalyst. The resulting composite was characterized using X-ray diffraction, scanning electron microscopy, nitrogen adsorption/desorption isotherms, thermal analysis, X-ray photoelectron spectroscopy, and UV–Vis diffuse reflection spectroscopy. The Fe₃O₄/MIL-101 composite possesses a large surface area and mesoporous structure and exhibits a good photocatalytic activity for the MB degradation in the visible light region. A kinetic model for dye degradation over this heterogeneous catalyst was proposed by combining the parameters of the Langmuir isotherms and the kinetics of the unimolecular reaction. The proposed model fixes well with the experimental data. The mechanism of MB photocatalytic degradation is also addressed. The catalyst is stable after three recycles, which makes it a potential candidate for environmental restoration.