▎ 摘　　要

Fe3O4 and Pd nanoparticles were assembled on sulfonated graphene (s-G) by an easy chemical approach and characterized by transmission electron microscopy, X-ray diffraction and energy dispersive X-ray spectroscopy. The resulting material could be dispersed homogeneously in water or water/ethanol and further used as an excellent semi-heterogeneous catalyst for the Suzuki-Miyaura cross-coupling reaction in an environmentally friendly solvent under ligand-free ambient conditions. The high heterogeneous catalytic activity appears to be due to the small size of Pd nanoparticles and homogeneous distribution of the nanoparticles on the Fe3O4/s-G matrix. In addition, the catalytic activity did not deteriorate even after repeated applications, which may be due to the easy and efficient magnetic separation of the catalyst and the high dispersion and stability of the catalyst in an aqueous solution.