Transforming in-situ grown chitosan/ZIF-67 aerogels into 3D N-doped Co/CoO/carbon composites for improved electromagnetic wave absorption

Nowadays there is much room for improvement in the designed synthesis of high-performance electromagnetic wave absorbers by combining metal-organic frameworks (MOFs) and biomass components. Herein, 3D N-doped porous carbon cobalt/cobalt oxide (NPC/Co/CoO) composites were successfully prepared by transforming in-situ grown ZIF-67 clusters on a chitosan matrix. Analysis results showed that the N-doped carbonaceous composites obtained had unique porosity, high specific surface area, and defect-enriched structure, which provided numerous paths for electron transfer , leading to big benefits to interfacial polarization and dipole polarization. Most importantly, the ferromagnetic resonance and magnetic coupling were enhanced by ZIF-67-derived Co/CoO nanoparticles . By adjusting the content of metallic cobalt salt, pyrolysis temperature, and sample filling content, the optimal impedance matching properties of the composites could be optimized. When the matching thickness is 2 mm, the RL min of NPC/Co/CoO-10/700–30 wt% achieved − 48.97 dB at 13.52 GHz, and the effective absorption bandwidth exceeds 5.36 GHz. The composites with excellent performance prepared by a controllable process using chitosan and ZIF-67 might be a promising alternative for the large-scale preparation of high-frequency electromagnetic wave absorbers.