Facile design of sea cucumber-like MOF-derived Fe-Co bimetallic autocatalytic carbon nanotube composites with enhanced microwave absorption properties.

Thin properties and efficient absorption performance are two significant factors in the practical application of electromagnetic wave absorbers, but still face considerable conflicts. Three-dimensional (3D) Carbon Nanotube (CNTs) interpenetrating network structure has been proved to be an effective strategy to obtain high performance electromagnetic waves (EMW) absorption materials. We report a 3D sea cucumber-like nanomaterial that uses pyrolysis to self-grow CNTs on the surface of bimetallic metal-organic frameworks (MOFs). FeCo bimetallic MOF were successfully prepared and CNTs were grown after the pyrolysis of bimetallic MOF. The excellent EMW absorption performance of FeCo/CNTs composites was attributed to its multiple absorption mechanism. Electromagnetic analysis showed that the 3D structure increases the multiple reflections of the EMW and the CNT produces sufficient polarization effects. The interconnection of CNTs provides more opportunities for electron leap and electron hopping. When the matched thickness is 1.38 mm, the performance of EMW absorption properties showed a minimum reflection loss of − 59.24 dB at 17.10 GHz. Moreover, the ultrathin FeCo/CNTs composites could reach an effective absorption of 10.96 GHz (60.9% of 2–18 GHz) showing an ultra-wide absorption. This work provided options for the modification of MOFs derivatives as excellent candidates for EMW absorbers. • FeCo multi MOF were successfully prepared and self-grown CNTs after pyrolysis. • The 3D structure can extend the transmission path of electromagnetic waves and increase the attenuation effect. • The excellentEMWabsorption performance is mainly attributed to magnetoelectric synergistic effect between FeCo and CNTs. [ABSTRACT FROM AUTHOR]