▎ 摘　　要

Hierarchical graphene@Fe3O4@SiO2@polyaniline quaternary composite is fabricated subtly. Their microwave absorption properties are also investigated in the 2-18 GHz frequency range. Transmission electron microscopy (TEM) and scanning electron microscope (SEM) reveal that Fe3O4@SiO2@polyaniline core@shell@shell heteronanostructures are densely covered on the surfaces of graphene, and form hierarchical structures. Compared with two-dimensional binary nanocomposites of graphene@Fe3O4, the hierarchical structure exhibits enhanced EM absorption in terms of both the maximum reflection loss value and the absorption bandwidth. The maximum reflection loss value can reach -40.7 dB at 12.5 GHz with a thickness of 2.5 mm and the bandwidth corresponding to the reflection loss below -10 dB is 5.8 GHz (from 10.5 to 16.3 GHz). (C) 2015 Elsevier B.V. All rights reserved.