Hierarchical Fe₃O₄@carbon@MnO₂ hybrid for electromagnetic wave absorber

In this work, a novel Fe₃O₄@C@MnO₂ hybrid was successfully synthesized via facile method. The morphology, structure, chemical composition, magnetic behavior and EM wave absorbing performance of the hybrid were systematically investigated. Results indicate that the hybrid possesses uniform hierarchical and mesoporous structure. The magnetic saturation(Ms) value of the hybrid is 19.8 emu g^-1, which is beneficial to improve magnetic loss. According to its reflection loss curve, the hybrid performs superior EM wave absorption capacity, with a minimum reflection loss value and effective absorbing bandwidth of -35 dB and 5 GHz when the specimen thickness is 2.7 mm. The excellent performance of this hybrid can mainly be attributed to its ideal matching of magnetic loss and dielectric loss, large specific surface area, mesoporous structure and interfacial polarizations. Such new material has the potential to be a superior electromagnetic wave absorber, or applied as a functional filler to modify resin matrix.