Amorphous Carbon With Quasi‐Continuous sp 2 Domain Loaded by Single Fe Atoms for Enhanced Electromagnetic Wave Absorption

ABSTRACT Amorphous carbon is a promising electromagnetic wave (EMW) absorption material due to its abundant conjugated/non‐conjugated interfaces. However, the discrete sp 2 domains in traditional amorphous carbon are difficult to form a continuous transmission channel of electrons, resulting in insufficient dielectric loss at low filling level. Herein, a quasi‐continuous sp 2 domain is successfully constructed in amorphous carbon through the bubble method assisted by metal salts. It not only retains the abundant conjugated/non‐conjugated interfaces, but also constructs a channel of electron transport, significantly enhancing dielectric loss. Furthermore, the single Fe atoms (C800/NFe) are loaded on the amorphous carbon with quasi‐continuous sp 2 domains by selecting ferric chloride as Fe precursor. Thanks to the continuous transmission channel of electrons and abundant Fe‐N 4 dipoles in the C800/NFe, an effective absorption bandwidth of 8.0 GHz at a filling ratio of only 7 wt.% is achieved, which is significantly superior to the reported powdered absorbing materials. Combining experiments and theories, the origin of unique dielectric properties for amorphous carbon with ordered structures on atomic‐scale is elucidated, and the frequency‐dependent relationship between interface polarization and dipole polarization is revealed. This provides a theoretical framework and technical paradigm for the design of high‐performance EMW absorption materials.