Sustainable synthesis of tunable 2D porous carbon nanosheets toward remarkable electromagnetic wave absorption performance

The realization of microwave absorbers that demonstrate wide frequency bands and strong absorption properties, especially for realizing multi-band absorption characteristics, presents an ongoing challenge in the field. Herein, we reported on a simple and sustainable method for the fabrication of gram-scale B/N co-doped porous carbon nanosheets (PCNs). These PCNs exhibited excellent microwave absorption performance, and their intrinsic electromagnetic wave absorption performance can be tuned by adjusting the size of nanosheets and heteroatoms. The PCNs achieved dual-band absorption in the C- and Ku- bands. Furthermore, the GC20 achieved an RL_min value of −29.5 dB at a thickness of 1.7 mm, with an effective adsorption band (EAB) of 7.2 GHz. The porous nanosheets, which provide the ideal synergistic effect of polarization loss and conductivity loss, were the factors that contributed to these desirable features. These absorbers with multi-band absorption are not only expected to address the prevalent issue of narrow EAB but also fulfill the requirements for applications in the different frequency bands, inspiring innovative designs of multi-band electromagnetic absorbers.