Cage-structured CoFe2O4@CNTs from Fe–Co-MOF confined growth in CNTs for high electromagnetic wave absorption performances

The CoFe2O4 polyhedron encapsulated by the interconnected carbon nanotubes (CNTs) network has been successfully prepared from analogous metal-organic framework (MOF) precursor, which has bimetallic species (Fe and Co) and organic ligand (2, 5-dihydroxyterephthalate acid, DHTA). The composite can be obtained through a simple hydrothermal process and subsequent calcination. The results demonstrate that the minimum reflection loss of the CoFe2O4@CNTs can reach −34.6 dB with thickness of 2.5 mm at 13.4 GHz, as well as the effective absorption bandwidth reaches 7.1 GHz (10.0–17.1 GHz). This work proves that the 3D conductive network CNTs coated CoFe2O4 composite can provide novel ideas for the design of high-absorptive microwave absorbers and the preparation of CNTs-modified metal composites.