Bimetallic ZIF-derived conductive network of Co–Zn@NPC@MWCNT nanocomposites for efficient electromagnetic wave absorption in the whole X-band

Abstract

Due to bimetallic MOFs (metal–organic frameworks) possessing diverse structure topologies and superior properties, herein, we used bimetallic ZIFs (zeolitic imidazole frameworks) of MOFs as precursors via the wet chemical and calcination method to fabricate zinc-embellished Co–Zn@NPC@MWCNT nanocomposites with porous conductive carbon-based networks The abundant carbon defects, zinc evaporation, and N-atom doping resulted in the emergence of dipolar/interface polarization, which is good for dielectric loss. The high porosity and large specific surface area were instrumental in the attenuation of multiple scattering and endowed the absorber with an excellent absorption performance. With merely 15 wt% filled loading and 3.187 mm thickness, the obtained composites under the optimized carbonization temperature (800 °C) exhibited double absorption peaks: the RL_min (minimum reflection loss) reached −76.18 dB@12.88 GHz and −33.09 dB@7.76 GHz, respectively. Moreover, a wide absorption bandwidth can be up to 6.56 GHz (7.2–13.76 GHz) with 3.0 mm thickness, distributed in three frequency bands: 20% of the C band, 100% of the X band, and 29.3% of the Ku band. In addition, the conductive network structure of composites was also beneficial for electromagnetic (EM)-wave absorption. An easy preparation process and low cost can further promote the commercial potential of our obtained bimetallic MOF-based material as an EM-wave absorber.