Heterostructured CoFe@C@MnO2 nanocubes for efficient microwave absorption

Abstract

The rational design of hierarchical structures with multi-heterogeneous components provides a promising pathway to develop advanced absorbers, but it remains a great challenge. Herein, we demonstrate the construction of three-layered CoFe@C@MnO2 hierarchical nanocubes to address this challenge, which involved the creation of metal organic framework-derived nanocubes consisting of CoFe nanoparticles embedded within porous carbon and the growth of MnO2 nanoparticles on the nanocubes. This delicate design not only enabled the synergistic effects of the magnetic loss of the magnetic CoFe and the intrinsic dielectric losses of the dielectric materials C and MnO2 but also facilitated multiple interface polarization and appropriate impedance matching. Benefiting from these structural and compositional features, the as-synthesized CoFe@C@MnO2 nanocubes achieved a minimum reflection loss of −64 dB at 15.6 GHz with a thickness of 1.3 mm and a maximum absorption bandwidth of 9.2 GHz from 8.8 to 18 GHz for −10 dB at a thickness of 1.6 mm.