Preparation and microwave absorption properties of ZnO@FeO@RGO composites.

Different processes are used to design unique microstructures of absorbing materials to meet the requirements of "thin, light, wide and strong" and improve the absorption efficiency of electromagnetic waves. The ZnO@FeO nanomaterial with a unique spindle flower structure was successfully prepared by a hydrothermal method and an annealing process. Then, the ZnO@FeO@RGO composite was obtained by loading the prepared ZnO@FeO nanomaterial on the RGO surface. The crystal structure, morphology, electromagnetic parameters and microwave absorption properties of the synthesized nanocomposites were characterized by changing the amounts of Zn(CHCOO)·2HO and GO, respectively. The wave absorption properties of pure FeO, ZnO@FeO and ZnO@FeO@RGO composites were compared. It was found that the ZnO@FeO@RGO composite exhibits stronger microwave absorption performance. When mixed with paraffin wax at 50 wt%, the thickness of the absorption layer was only 2.5 mm, the reflection loss (RL) at 11.36 GHz reached -57.91 dB, and the effective absorption bandwidth was 4.24 GHz (9.44-13.68 GHz). ZnO@FeO nanocrystals can inhibit the agglomeration of RGO and improve the impedance matching between the heterostructural interface and RGO. Therefore, the composite can be used as an effective microwave absorber.