Carbon nanotubes decorated Co/C from ZIF-67/melamine as high efficient microwave absorbing material.

The problem of unstable structure and poor impedance matching of single metal-organic framework (MOF) can be avoided by sintering MOFs and melamine composites to fabricate carbon nanotubes-coated cobalt/carbon nanoparticles (Co@C/CNTs). By regulating the mixing ratio of MOF and melamine, different lengths and amount of carbon nanotubes coated porous cobalt/carbon polyhedrons can be obtained, and the catalytic capability of cobalt can be affected to obtain carbon with different degrees of graphitization. The appropriate ratio can change the dielectric magnetic parameters to optimize the impedance matching of the material. As the result, when the mixing ratio of ZIF-67 and melamine was 1:1, the product Co@C/CNTs/PVDF-1:1 shows the lowest reflection loss (−57.6 dB) at the filling amount of 15 wt% with the thickness of 3.01 mm. The effective absorbing bandwidth (EAB) could achieve 5.4 GHz from 12.6 GHz to 18.0 GHz under the filler loading of 10 wt% with the thickness of 2 mm. These results inaugurate a new avenue for obtaining excellent absorbing composites with lightweight, wide EAB and strong absorbing performance. [Display omitted] • Carbon nanotubes-coated cobalt/carbon nanoparticles (Co@C/CNTs) with excellent performance was successfully synthesized. • An excellent reflection loss (RL) of −57.6 dB with a low filler loading (15 wt%) and thin thickness (3.01 mm). • Effective absorption bandwidth (<−10 dB) can be up to 5.4 GHz under a single thickness (2.00 mm). • The synergistic effect between magnetic components and carbon-based show up good impedance matching. [ABSTRACT FROM AUTHOR]