Synthesis of polyaniline nanorods and Fe^sub 3^O^sub 4^ microspheres on graphene nanosheets and enhanced microwave absorption performances

The hierarchical structure of Fe3O4@graphene@PANI was designed and successfully fabricated using hydrothermal and in-situ polymerization methods. The as-synthesized (Fe3O4@ graphene@PANI) composite was characterized by a series of tests (XRD, FTIR, XPS, FESEM and TEM). FESEM and TEM results reveal that PANI nanorod arrays and Fe3O4 microspheres are covered on the surface of graphene, with a homogeneous distribution. Studies of microwave absorption properties indicate that the Fe3O4@graphene@PANI composite exhibits a proper attenuation constant and impedance matching, which leads to favourable microwave absorption properties. For the Fe3O4@graphene@PANI composite, the maximum reflection loss (RL) is −43.7 dB at 10.7 GHz and the effective absorption bandwidth below −10 dB can achieve 5.4 GHz (6.8–12.2 GHz) with a matching thickness of 3 mm. Findings demonstrate that the Fe3O4@ graphene@PANI composite might be a promising absorber for broad bandwidth, strong absorption electromagnetic wave absorbing materials.