Hierarchical bath lily-like hollow microspheres constructed by graphene and Fe3O4 nanoparticles with enhanced broadband and highly efficient low-frequency microwave absorption

Hierarchical bath lily-like hollow microspheres constructed by graphene nanosheets and Fe3O4 nanoparticles (HGSs/Fe3O4) are synthesized via microemulsion and impregnation methods to improve impedance matching and introduce magnetic loss. A more stable confining configuration can be generated by impregnating Fe3O4 nanoparticles in the wrinkles on the surface of hierarchical hollow graphene microspheres (HGSs), which in turn leads to their corresponding derivatives exhibiting the increasing properties of multifrequency electromagnetic wave absorption trait. Combining with hierarchical and hollow structures, both hierarchical bath lily-like absorbents (HGSs and HGSs/Fe3O4) have excellent S-band absorption properties as well as improved reflection loss values, appraprate to portable electronics. The resulting hierarchical HGSs/Fe3O4 composites possess much enhanced electromagnetic wave absorbing performance, whose minimum reflection loss (RLmin) is −58.91 dB and the efficient absorbing bandwidth is 5.61 GHz. The structure also promises the absorbent the low-frequency absorbing ability, which shows a −33.03 dB at 3.89 GHz. This work provides a feasible choice for the structural design and hybridization of graphene-based electromagnetic wave absorbents used in multi/low frequency.