Surface-Oxidized Amorphous Fe Nanoparticles Supported on Reduced Graphene Oxide Sheets for Microwave Absorption

A simple one-pot chemical reduction synthesis is provided to prepare a novel metal–graphene nanostructure, in which surface-oxidized amorphous Fe nanoparticles grow uniformly on reduced graphene oxide (rGO) sheets to form amorphous-Fe/rGO nanocomposites. A relatively low coercivity of 60.2 Oe is achieved in these magnetic graphene-based nanosheets supported with uniformly distributed amorphous Fe nanoparticles. The dielectric properties of amorphous-Fe/rGO nanocomposites are effectively tuned by suitable rGO additions. Improved impedance matching resulting from balanced magnetic and dielectric loss can be obtained in the Fe/5 wt % rGO nanocomposites, which results in their good wave absorption performance containing a high maximum reflection loss (−72.8 dB at 4.48 GHz) for a 3.26 mm thickness and a wide absorption bandwidth (5.90 GHz, <−10 dB). The simple synthesis, high structural stability, low density, and excellent wave absorption properties for amorphous-Fe/rGO nanocomposites enable their significant latent applications in lightweight electromagnetic microwave absorbers.