Magnetic Fe3O4 supported Mn3O4 nanoparticles (Fe3O4/Mn3O4) were prepared by the solvent thermal method, and its structure was characterized by XRD, XI'S, TEM, and FT-IR technologies. The resulting Fe3O4/Mn3O4 nanoparticles could be used as an excellent heterogeneous catalyst for the aerobic oxidation of the biomass-derived model molecule 5-hydroxymethylfurfural into 2,5-diformylfuran (DFF) under benign reaction conditions. Some important reaction parameters such as reaction temperature, catalyst amount, solvent, oxidant, and oxygen pressure were explored and high DFF yield of 82.1% with HMF conversion of 100% were obtained in DMF under optimal reaction conditions. More importantly, the catalyst could be readily separated from the reaction mixture by a permanent magnet, and recycled up to 6 times without the significant loss of its catalytic activity. (C) 2013 Elsevier B.V. All rights reserved.