Fabrication of porous graphene-like carbon nanosheets with rich doped-nitrogen for high-performance electromagnetic microwave absorption

Abstract

The facile fabrication of lightweight electromagnetic microwave (EM) absorption materials is still in urgent demand due to the increasingly serious electromagnetic pollution and the high requirements of military defense. Herein, nitrogen-rich graphene-like carbon nanosheets (NGs) with porous network structure have been prepared by g-C3N4 template-directed chemical vapor deposition combined with high-temperature treatment process which eliminates the cumbersome template removal, achieving the porosity engineering and high nitrogen doping simultaneously. The conduction loss could be tailored by the configurations of doping N atoms through our method, which plays a dominant role in determining the dielectric behavior in NG materials. The as-prepared NGs with intriguing features possess strong EM attenuation capacity originating from the dielectric loss, the multiple scatterings as well as the balanced impedance match. The optimized NG sample with low loading of only 5 wt% and thin thickness of only 1.8 mm exhibits effective EM absorption performance with the best RLmin of −50.2 dB and the effective absorption bandwidth is about 5.9 GHz at 2 mm. Our work not only provides a promising candidate as effective filler in lightweight EM absorption composites without decoration of other nanomaterials but also valuable insights into the mechanism.