Achieving high-efficiency and broad bandwidth with low filler loading for hierarchical Fe3O4/Co-MOF absorbers

Metal-organic frameworks (MOFs) with intrinsic porosity and high specific surface area have aroused broad interests as a promising electromagnetic (EM) absorbing material. However, the introduction of magnetic components in MOFs has remained as a formidable obstacle for subsequent development. Herein, Fe3O4/Co-MOF composites were fabricated via a facile and scalable co-precipitation process. The microstructure and morphology of the composites were characterized and the combination of hollow Fe3O4 and Co-MOFs was found to contribute towards the dissipation of incident waves due to the magnetic-dielectric synergistic effect. Impressive microwave absorption ability was obtained with a minimum reflection loss of -56.1 dB over a qualified bandwidth (7.9 GHz) at 2.0 mm. Moreover, the radar cross section simulation further confirmed the effective suppression of radar wave scattering using Fe3O4/Co-MOF composites. This study provides a versatile strategy for designing magnetic-dielectric composites based on MOFs as effective and broadband microwave absorbers.