Fabrication of iron manganese metal-organic framework derived magnetic MnFe2O4/C composites for broadband and highly efficient electromagnetic wave absorption

Designing and manufacturing advanced electromagnetic wave absorbing materials with comprehensive excellent absorption performance remains a huge challenge. Metal-organic framework (MOF) has been widely considered as an ideal precursor to prepare novel electromagnetic wave absorbers. In this work, MnFe2O4/C composites derived from FeMn-MOF were fabricated by a two-step route of solvothermal reaction and pyrolysis treatment. The results of micromorphology analysis showed that the shape of MnFe2O4/C frameworks gradually changed from regular octahedron to irregular polyhedron with the increase of pyrolysis temperature. Furthermore, the pyrolysis temperature had a significant impact on the crystal structure, degree of graphitization, magnetic properties and electromagnetic parameters of MnFe2O4/C composites. It was noteworthy that the as-prepared MnFe2O4/C composite pyrolyzed at 700 C-degrees exhibited the best electromagnetic wave absorption performance. The minimum reflection loss was as low as -47.1 dB and maximum effective absorption bandwidth reached up to 7.04 GHz (10.88-17.92 GHz, covering part of X band and almost the entire Ku band) at a matching thickness of 2.66 mm. In addition, the underlying electromagnetic attenuation mechanisms were also elucidated. This paper was expected to provide insights for the preparation of broadband and highly efficient carbon-based electromagnetic wave absorbers derived from MOF.