Yolk-shell Fe3O4@MOF-5 nanocomposites as a heterogeneous Fenton-like catalyst for organic dye removal

Abstract Yolk-shell Fe3O4@MOF-5 nanocomposites were synthesized by utilizing a simple solvothermal method. The physicochemical properties of the yolk-shell Fe3O4@MOF-5 nanocomposites were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) and vibrating sample magnetometer (VSM) methods. The nanocomposites had a catalytic yolk, a hollow cavity and a porous shell. The nanocomposites had relatively high specific surface area of 203 m2 g−1 and showed superparamagnetic property. The catalytic activities of the yolk-shell Fe3O4@MOF-5 nanocomposites were evaluated by using methylene blue dye as a model pollutant. It is demonstrated that the yolk-shell Fe3O4@MOF-5 nanocomposites as a heterogeneous Fenton-like catalyst exhibited excellent catalysis since the internal cavity provided a relatively stable micro-environment for the reaction of the active ·OH radicals and the pollutants on the basis of the confinement effect. Furthermore, the yolk-shell Fe3O4@MOF-5 nanocomposites could be lightly separated from the pollutant solution by an external magnetic field and maintained good catalytic activity after five recycles, indicating the good stability of the nanocomposites.