Engineering core–shell heterocomposites of integrated 0D ZIF-8 (Zn) attached on 1D MIL-68 (In) nanorods for high performance electromagnetic wave absorption

Abstract

With the booming development and wide applications of smart and portable devices, electromagnetic wave (EMW) pollution and radiation are attracting more and more attention. EMW absorption materials play a vital role in solving the above problems. It is a still challenge to simultaneously realize strong reflection loss (RL), broad effective absorption bandwidth and lightweight of EMW absorption materials. In this paper, ZnO/C@In/C core–shell porous carbon hetero-rods were designed and synthesized via the pyrolysis of double MOFs with core–shell structure (MIL-68 (In) nanorods coated by ZIF-8 (Zn) dodecahedron nanoparticles). The ratio of MIL-68 (In) and ZIF-8 (Zn) in ZnO/C@In/C heterostructure composite was adjusted to achieve the impedance matching, resulting in most EMW entering composites. ZnO/C@In/C-0.136 exhibits a minimum RL of −56.75 dB at 16.34 GHz and broad effective absorption bandwidth of 6.76 GHz under the thickness of 2.36 mm, which is due to the impedance matching and high attenuation ability coming from a large number of interfaces. The finding of this study not only provides a facile preparation method of porous carbon with core–shell structure, but also offers a strategy for achieving strong RL and wide effective absorption bandwidth via synergistic effect of dielectric loss and impedance matching.