Improvement of interfacial polarization and impedance matching for two-dimensional leaf-like bimetallic (Co, Zn) doped porous carbon nanocomposites with broadband microwave absorption

Two-dimensional (2D) carbon matrix nanocomposites are promising for efficient microwave absorption on account of the large specific surface area, the small size effect of nanoparticles and the multiple attenuation mechanisms to electromagnetic waves. Herein, we prepared innovative two-dimensional leaf-like bimetallic (Co, Zn) doped porous carbon nanocomposites (BPCNs) via a simple aqueous-phase self-assembly process and subsequent heat treatment. An in-depth study of the relative metal content on the leaf-like morphology, porous structure and microwave absorption properties has been carried out in detail. The research results show that the BPCNs possess large surface areas and abundant mesoporous, and metallic nanoparticles can be well dispersed in the carbon skeleton after high-temperature calcination. Moreover, the BPCNs exhibited excellent microwave absorption properties with the maximum effective absorption bandwidth (EAB) of 5.7 GHz at the thickness of 2.5 mm when Co relative content increased to 40% (BPCN-0.4), and the minimum reflection loss (RL) can reach to -45.2 dB. The broad EAB and strong RL value can be attributed to the small size effect of Co and Zn nanoparticles, the improved interfacial polarization and the optimized impedance matching. Considering that, the 2D leaf-like BPCNs can be an innovative candidate as lightweight and efficient microwave absorber.