▎ 摘　　要

Graphene as an important two-dimensional one-atom-thick nanosheet can be regarded as a solid and also a molecule. In this paper, we focused attention on the coordination ability of doping-induced defects, micro-scale size and atomic thickness of graphene, and anchored oxygen-donor coordination of graphene oxide to ferric ions, forming a giant flat iron complex. As well as graphene oxide, as-obtained graphene oxide-Fe(III) complexes were characterized by transmission electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy, and so on. It was demonstrated that graphene oxide-Fe(III) complexes could be well dispersed in water, with size up to micrometers and atomically thin. Under visible-light irradiation, graphene oxide-Fe(III) complexes displayed homogeneous catalytic ability of H2O2 activation, and could be easily removed by simple filtration or centrifugation, showing significant advantages in both homogeneous and heterogeneous catalysis.