▎ 摘　　要

Composites (Fe3O4@HG) of hydrophilic graphene (HG) and Fe3O4 from an iron precursor of FeC1(3) .6H(2)O and (NH4)(2)Fe(SO4)(2). 6H(2)O were prepared without any organic surfactants by a facile chemical co-precipitation method. Fe3O4 nanoparticles in Fe3O4@HG were about 15 nm in dimension and were ultra dispersed on HG nanosheets. Fe3O4@HG exhibited paramagnetic characteristic and better stability in water. Photo-Fenton reaction results demonstrated that Fe3O4@HG composites could degrade methyl orange (MO) dye with high efficiency in a short time. When the loading capacity of HG in Fe3O4@HG composites was 53.81 wt%, the catalytic efficiency could reach 87.68% after 30 min and the catalytic rate could be 0.055 mg min(-1) in the first five minutes. A possible catalytic cycle for Fe3O4@HG catalyzed photo degradation of the dye was elucidated. The photo-generated electrons were transferred rapidly on the surface of HG and promoted the conversion efficiency of Fe3+/Fe-2+ due to the good absorption and electronic conductivity of HG. The composites would be applied as photo-catalysts for treatment of wastewater. (C) 2016 Elsevier B.V. All rights reserved.