Microwave Absorption Performance Evaluation of Carbonized Derivatives of Fe₃O₄@MOF-74 with Controllable Morphologies

Researchers are constantly trying to exploit the unique advantages of metal–organic framework (MOF) precursors to develop new composite absorbing materials. Although many magnetic absorbers based on precursor metal central ions have been constructed, there are relatively few reports on the introduction of magnetic components through external aids to enhance the magnetic properties of materials. In this work, Fe3O4 nanoparticles are used for composites with MOF-74 containing Mg2+, Ni2+, Zn2+, Co2+, and Cu2+ to construct magnetic particle precursors, which were carbonized to form stable magnetic carbon materials. With the assistance of Fe3O4 nanoparticles, MOF-74 containing different metal central ions was fabricated with different hierarchical pore structures. The comparative analysis and systematic electromagnetic parameter study show that the composite particles possess an excellent interface polarization ability and electromagnetic wave absorption performance due to their specific morphology, reasonable composition, and the strengthening effect of magnetic particles. The minimum reflection loss (RLmin) of Fe3O4@Ni-C reaches −59.4 dB@9.9 GHz, and the effective absorption bandwidth (EAB) of Fe3O4@Co-C reaches 6.8 GHz@3.1 mm. This work provides an idea for the design and preparation of magnetic composite carbon absorbers.