▎ 摘　　要

The well-established structure and ultra-fine nanoparticles are vital for high-performance microwave absorption materials. Herein, three-dimensional hydrophobic graphene aerogels decorated with ultra-fine Fe3O4 nano crystals composites (HGAFX, X stands for pyrolysis temperature) were successfully constructed via chemically self-assembly and in situ pyrolysis. Remarkably, the hybrids with only 5% filling contents exhibited excellent microwave absorption performance (MAP) in terms of both minimum reflection loss (RLmin) and effective absorption bandwidth (EAB), outperforming the most reported microwave absorbers. Moreover, the magnetic graphene aerogels composites possess strong hydrophobicity, endowing them attractive functions of selfcleaning, waterproof, anti-icing, and corrosion resistance. Importantly, experimental results and theoretical calculations indicate that superior MAP can be carried out by reasonably regulating the electromagnetic parameters. Considering the excellent absorption capacities, our strategy opened a novel way for anchoring ultra small nanoparticles on graphene sheets as highly effective synergistic microwave absorbers at low filling contents.