Porous composites of vertical graphene sheets and Fe3O4 nanorods grown on Fe/Fe3C particle embedded graphene-structured carbon walls for highly efficient microwave absorption

It is significantly important but remains challenging to prepare high performance microwave absorption materials in civil and military fields. Here, the Fe/Fe3C particles embedded in graphene-structured porous carbon (FGPC) served as a three-dimensional framework is prepared by simple carbothermal reduction, then vertical graphene nanosheets (VGSs) and Fe3O4 nanorods are successively grown on FGPC (FGPC/VGSs and FGPC/VGSs/Fe3O4) by thermal chemical vapor deposition, solution method, and subsequent heat treatment. As for comparison, VGSs and Fe3O4 nanorods grown on GPC without Fe/Fe3C particles (GPC/VGSs and GPC/VGSs/Fe3O4) are also prepared. The microwave absorption properties of them are investigated. Benefiting from the multi-component integration and well-designed structure, the FGPC/VGSs/Fe3O4 exhibits impressive microwave absorption performance with an optimal reflection loss of -64.7 dB at 15.3 GHz, a matching thickness of 1.7 mm, filler loading of 12 wt%, and effective absorption bandwidth of over 4.8 GHz. This results from the balance of impedance match and attenuation capability. In detail, the introduction of magnetic particles and nanorods improves the impedance match. The multiple reflections and scatterings, moderate conductive loss and magnetic loss enhance the attenuation of microwaves. Thus, this work might open an avenue to design a highly efficient and lightweight multi-dimensional multiple component microwave absorbers. (C) 2022 Elsevier B.V. All rights reserved.