Enhanced microwave absorption performance in an ultralight porous single-atom Co–N–C absorber

Improving the interfacial impedance matching and attenuation ability of a microwave absorber is an important strategy to obtain excellent microwave absorbing performance. Here, we prepared an ultralight, hierarchical porous single-atom Co–N–C microwave absorber, in which evenly distributed single-atom Co is anchored in a porous N-doped carbon framework by N–Co bond via a facile bio-inspired method. These doped single atoms provide abundant highly active atomic absorption sites on the carbon skeleton, and considerable defects including pyridinic-N, pyrrolic-N, oxidized N, and so forth are introduced into the carbon framework owing to single Co atom doping. These doped single Co atoms and introduced defects act together as strong dipolar/interfacial polarization units, which lead to better impedance matching and a significant increase in attenuation capability of the absorber. The metal Co exists in form of a single atom, benefiting light weight of the absorber. Therefore, an extremely strong reflection loss (RL) value of − 60.9 dB is achieved at a lower filler content of 10 wt% with the absorber thickness of 2.5 mm, and the effective frequency bandwidth covered from 10.4 to 15.1 GHz with a thickness of 2.0 mm at a low filler content of 10 wt%. This research offers a novel route for designing a microwave absorber to improve microwave absorption performance and is expected to a wider range of absorbing materials with different structures.