Bimetallic MOFs derived FeM(II)-alloy@C composites with high-performance electromagnetic wave absorption

The realization of balance between relative permittivity and permeability is still a great challenge in the development of microwave absorption materials. Based on the controllable MOFs precursor, bimetallic Fe/M (M = Co, Ni, Mn) doped carbon derived from pyrolyzing bimetallic MOFs (FeM-MIL-88B) exhibits intriguing microwave absorption property. By tuning the second metal source and the ratio of Fe/M, in this work we realize impedance matching between free space and the absorber. Optimized FeCo2@C exhibits strong EMW absorption performance (-71.4 dB) and broad bandwidth (14.2 GHz) with a low filler loading of 25 wt%. The synergistic effect of the bimetal source on carbonization process and electric/magnetic properties prove that rationally doping the second metal source into the Fe-MOFs precursor to generate bimetallic magnetic nanoparticles/C material play an intensified role to tune the microwave absorption performance.