It is of great significance to develop lightweight and efficient electromagnetic wave (EMW) absorption materials to counter the problems of electromagnetic interference, information security and national defense security. In recent years,nanoporous carbon composites derived from metal-organic frameworks (MOFs) have gained numerous attentions in the field of EMW absorption. Benefited from the highly adjustable pore structures and the tailored components and microstructures of MOFs, the in-situ generated metallic microwave absorption units in carbon matrix result in rich interfaces as well as compositions. Together with the cross-linked conductive network, the microwave loss mechanisms can be greatly enriched,leading to enhanced EMW absorption capability. The rational design of various components and the controllable construction of microstructures are the key to regulate the electromagnetic parameters. The rational design and performance regulation strategy of MOFs-derived carbon-based EMW absorbers in recent years are reviewed regarding incorporated metal types and spatial arrangement, heterogeneous structure of MOFs and porous structure of carbon matrix. Finally, the challenges and perspectives of MOFs-derived carbon composites in the application of EMW absorption are also presented.

With the popularization of high-frequency communication technology, the problem of electromagnetic radiation has received increasing attention. The construction of novel electromagnetic wave (EMW) absorption materials based on conductive metal-organic frameworks (MOFs) has become a research hotspot in recent years. In this work, MXene modified MOF/polypyrrole (PPy) was proposed, with which high-performance EMW absorption materials with broadband and strong absorption were successfully obtained through the cooperative optimization of dielectric loss of the three components. When the filling content is only 10 wt.%, the minimum reflection loss (RL_min) of the composites can reach -56.21 dB at a thin thickness of 1.98 mm, while the maximum effective absorption bandwidth (EAB) can be up to 7.12 GHz (10.88-18.00 GHz), which is superior to the conductive MOF-based microwave absorbers reported in the open literture. By analyzing the components and microstructure of the materials, it is found that the excess PPy is not only polymerized in-situ in the pores and outer surface of UiO-66, but also loaded on the MXene substrate, which effectively builds up conductive network and promotes the conductive loss. Meanwhile, the ternary heterogeneous interface composed of UiO-66, PPy and MXene greatly enhanced the interfacial polarization loss, which further promoted the attenuation of electromagnetic waves. In addition, the simple preparation process and high yield of MXene/UiO-66/PPy have strong potential for large-scale production, which is promising to be applied in the field of electromagnetic protection.

Metal-organic frameworks (MOFs) derived metallic nanoparticles embedded nano-porous carbon (NPC) composites have shown to be promising microwave absorbing materials. Although MOF precursors with diverse compositions and morphologies have been extensively investigated, anionic MOFs are rarely explored for this utility. In addition to the metal sites and ligands on the MOF framework, the guest counter-cations in the void provide supplementary parameters to tune the capability of microwave absorption. Herein, we applied an anionic Ni_xCo_y-MOF featuring N-rich ligands and hierarchical porous structures as a precursor for microwave absorption. The obtained dielectric-magnetic Ni_xCo_y@NPC composites with rich N dopants and multiple hetero-interfaces promote the microwave attenuation capability through enhanced dipole/interfacial relaxation. The synergistic effects of magnetic loss and conduction loss induced by metallic nanoparticles (NPs) and porous graphitic layers further facilitate the microwave dissipation. More significantly, impedance matching can be effectively improved by tuning the Co/Ni amount in the precursors to realize the modulation of electromagnetic parameters. Consequently, Ni@NPC exhibits the optimal electromagnetic wave (EMW) absorption with minimum reflection loss of −66 dB at only 2 mm and broad effective absorption band covering 4.56 GHz at a thin thickness of 2.07 mm, making this material promising absorber for EMW elimination.