Synthesis of Fe3O4@ZnO/RGO nanocomposites and microwave absorption properties

Core-shell Fe₃O₄@ZnO microspheres supported by reduced graphene oxide (RGO) (Fe₃O₄@ZnO/RGO nanocomposites) with uniform size, high magnetization and excellent microwave absorption properties have been designed and synthesized by a simple hydrothermal method. The transmission electron microscopy and scanning electron microscopy characterization results reveal that Fe₃O₄@ZnO microspheres with core-shell structures are uniformly coated on both sides of the RGO nanosheets. Dielectric constants and microwave absorption properties of paraffin containing 50 wt% Fe₃O₄@ZnO/RGO were studied by a vector network analyzer between 2 ~ 18 GHz at room temperature. According to the electromagnetic (EM) characteristics, the Fe₃O₄@ZnO/RGO nanocomposites show excellent microwave absorption properties in the 2 ~18 GHz range, as evidenced by the wide effective absorption bandwidth (up to 12 GHz, with reflection loss RL <; - 10 dB) and a minimal RL (-34 dB) at 6.7 GHz. The results indicate that Fe₃O₄@ZnO/RGO nanocomposites may become attractive candidates for microwave absorption materials. Moreover, the intrinsic reasons for microwave absorption properties of the materials, and the formation mechanism based on the hydrothermal method were also proposed.