Hydrothermal synthesis and photo-Fenton degradation of magnetic MnFe2O4/rGO nanocomposites

Magnetic recoverable MnFe2O4/rGO nanocomposites were synthesized via a facile one-pot hydrothermal method. The microstructure, morphology, optical and magnetic property were characterized by X-ray diffraction, high-resolution transmission electron microscope, ultraviolet–visible spectroscopy, N2 adsorption–desorption technique, photoluminescence spectroscopy and vibrating sample magnetometer. The photo-Fenton degradation activity of the MnFe2O4/rGO composites was investigated using the methylene blue (MB) in aqueous solution under the simulated sunlight. The results show that MnFe2O4 nanoparticles with cubic spinel structure were loaded on the surface of rGO, possessing irregular ellipsoid with uniform particle size and good dispersion. The band gap of MnFe2O4/rGO is narrower than that of pure MnFe2O4 and exhibits redshift. The weak luminescence of MnFe2O4/rGO nanocomposites indicates the efficient separation of photoexcited electron/hole pairs. MnFe2O4/rGO nanocomposites display superior photo-Fenton degradation efficiency of MB, exhibit obvious room temperature ferromagnetism and can be readily recovered by external magnetic field. MnFe2O4/rGO nanocomposites exhibit the best degradation efficiency under the condition of pH 9, 0.5 mL H2O2 and 0.06 g mass fraction in photo-Fenton degradation of MB dye. The radical scavenger tests demonstrate that ·OH, e− and h+ are the main active species and play a decisive role, and rGO plays a vital role in synergistic enhancement of photo-Fenton degradation.