Zeolitic imidazolate frameworks (ZIFs), a group of metal-organic frameworks (MOFs), hold promise as building blocks in electromagnetic (EM) wave absorption/shielding materials and devices. In this contribution, we proposed a facile strategy to synthesize three dimensional ZIF-67-based hierarchical heterostructures through coordinated reacting a preceramic component, poly(dimethylsilylene)diacetylenes (PDSDA) with ZIF-67, following by carbonizing the PDSDA wrapped ZIF at high temperature. The introduction of PDSDA leads to a controllable generation of surface network containing branched carbon nanotubes and regional distributed graphitic carbons, in addition to the nanostructures with well-defined size and porous surface made by cobalt nanoparticles. The surface structures can be tailored through variations in pyrolysis temperatures, therefore enabling a simple and robust route to facilitate suitable structural surface. The heterostructure of ZIF nanocomplex allows the existence of dielectric loss and magnetic loss, therefore, yielding a significant improvement on EM wave absorption with a minimum reflection coefficient (RCmin) of-50.9 dB at 17.0 GHz at a thickness of 1.9 mm and an effective absorption bandwidth (EAB) covering the full Ku-band (12.0 GHz to 18.0 GHz).

The discovery of efficient electromagnetic wave absorbing materials for solving serious electromagnetic wave pollution is an urgent task. By rational design and assembly, a new three-dimensional metal–organic framework (MOF, CPT-1-Co) with the Co ions was constructed and employed as the precursor for the fabrication of Co/C composites via pyrolysis at high temperatures. The resultant Co/C composite pyrolyzed at 700 °C can absorb more than 90% of an EM wave at 2–18 GHz by the alternation of fabrication thickness. The effective absorption bandwidth can reach as high as 5.4 GHz at a thin thickness of 1.7 mm, which is superior to that of most EM wave absorbers. The bottom-up protocol in this report represents the first attempt to pyrolyze a new MOF for microwave absorber fabrication, which will provide valuable insight for designing more advanced MOFs and their applications in efficient electromagnetic wave absorption.

Design and fabrication of highly efficient electromagnetic wave absorbing materials are yet challenging tasks, mainly caused by the lack of the in‐depth understanding of structure–property relationship. Herein, significant morphology effect on electromagnetic wave absorption is uncovered by pyrolyzing two isomeric metal–organic frameworks (MOFs: MIL‐101‐Fe and MIL‐88B‐Fe). The resultant pyrolyzed nanocomposites from these two MOFs with different topology under same pyrolysis condition have almost identical chemical composition (i.e., element type, element content, and valence state) and microstructure (i.e., particle size, pore size, and volume). As far as it is known, this work represents the first study on morphology control for superior electromagnetic wave absorption in carbon‐included composite system. Notably, an excellent performance of minimum reflection loss of −59.2 dB with a thickness of 4.32 mm and effective absorption bandwidth of 6.5 GHz with a thickness of 2 mm are achieved by Fe/C‐700@101 (700 represent the pyrolysis temperature; 101 stands for MIL‐101 precursor) and Fe/Fe3C/C‐800@101, respectively. This contribution will shed the light on design of advanced electromagnetic wave absorbers in future, especially from the perspective of fine morphology control.

A hollow bimetallic metal organic framework was pyrolyzed to fabricate hollow ZnNiC nanocomposites for efficient microwave absorption.