Three-dimensional graphene supported Fe3O4 coated by polypyrrole toward enhanced stability and microwave absorbing properties

The composites GFPs were prepared through anchoring the microspheres of Fe3O4 cores coated with polypyrrole shells (Fe3O4@Ppy) on the three-dimensional (3D) graphene areogel (GA) with the one-step chemical reduction method. Good microwave absorption properties of the composites in 2−18 GHz can be obtained through tuning the content of Fe3O4@Ppy. For GFP1:3 the minimum reflection loss (RL) can reach −40.53 dB at 6.32 GHz and the effective bandwidth of the reflection loss peak with the thickness of 2.5 mm reaches 5.12 GHz. Especially, the stability of Fe3O4 can be improved due to the coating of Ppy shells. As expected, the enlarged dielectric properties derived from Ppy itself, the enhanced conductivity and abundant interfaces due to the introduction of Ppy as shells largely contribute to the improved microwave absorption capacity. The component synergy of 3D graphene, Ppy and Fe3O4 leading to the good impedance matching condition also plays a key role in achieving the enhanced microwave absorption performance. Most importantly, GFPs still maintain ultra-light nature. The contribution provides an effect avenue to prepare stable and light-weighted materials in a simple method for practical microwave absorption.