MOFs derived Fe/Co/C heterogeneous composite absorbers for efficient microwave absorption

Microwave absorbing materials (MAMs) can effectively attenuate microwave energy and avoid the secondary pollution of microwaves, showing great research significance. However, most of the reported MAMs are short of efficient electromagnetic wave absorption ability in low-frequency microbands (such as S-band in 2-4 GHz). Herein, we proposed a MOF on MOF design to obtain a Fe/Co/C multicomponent composite through the synthesis of ion-ligand of two MOFs and subsequent high-temperature pyrolysis, realizing the broadband microwave absorption(MA) and superb electromagnetic wave absorption in S band. ZIF-67 was grown in situ on micron-scale spindle NH2-MIL-88B (Fe) as the bearing matrix to obtain the precursor composed of Fe-MOF and Co-MOF. After pyrolysis at high temperature in an inert atmosphere, the organic components are carbonized to form a carbon layer coated with magnetic nanoparticles composed of Fe and Co. The characteristics of a rich heterogeneous interface and large specific surface area enhance the polarization ability of composite absorbent and the conduction dissipation path of electromagnetic wave. Besides, the composite absorbent can cover the absorption demand of 2-18 GHz with an adjustable thickness. We believe that this composite design of multiple MOFs can provide a new reference for the realization of efficient microwave absorption.

Automated summary

In this study, a multilayer metal-organic framework (MOF) design was proposed to obtain a Fe/Co/C multicomponent composite through synthesis and high-temperature pyrolysis of two MOFs. The composite exhibited broadband microwave absorption and superb electromagnetic wave absorption in the S-band. The composite absorbent had a rich heterogeneous interface and large specific surface area, enhancing the polarization ability and conduction dissipation path of electromagnetic waves. Additionally, the adjustable thickness of the composite absorbent covered the absorption demand of 2-18 GHz. This multi-MOF composite design provides a new reference for efficient microwave absorption.