Fabrication of hierarchical reduced graphene oxide decorated with core-shell Fe₃O₄@polypyrrole heterostructures for excellent electromagnetic wave absorption

The design of heterostructures with reasonable chemical composition and spatial structure is one of the effective strategies to achieve high performances electromagnetic wave (EMW) absorption. Herein, reduced graphene oxide (rGO) nanosheets decorated with hollow core-shell Fe3O4@PPy (FP) microspheres have been prepared by the combination of hydrothermal method, in situ polymerization method, directional freeze-drying and hydrazine vapor reduction. FP acting as traps can consume EMW trapped into their interior through the magnetic and dielectric losses. RGO nanosheets forming the conductive network are served as multi-reflected layers. Moreover, the impedance matching is optimized by the synergistic effect between FP and rGO. As expected, the synthetic Fe3O4@PPy/rGO (FPG) composite shows excellent EMW absorption performances with the minimum reflect loss (RLmin) of-61.20 dB at 1.89 mm and the effective absorption bandwidth (EAB) of 5.26 GHz at 1.71 mm. The excellent performances for the heterostructure are attributed to the synergistic effect of conductive loss, dielectric loss, magnetic loss, multiple reflection loss, and optimized impedance matching. This work provides a simple and effective strategy for the fabrication of lightweight, thin and high-performances EMW absorbing materials.