Facile fabrication of ultra-light N-doped-rGO/g-CN for broadband microwave absorption.

"Thin thickness", "lightweight", "wide absorption bandwidth" and "strong absorption" are the new standards of contemporary science and technology for microwave absorption(MA) material. In this study, N-doped-rGO/g-CN MA material was prepared for the first time by simple heat treatment, which the N atoms were doped into rGO and g-CN was dispersed on the surface of N-doped-rGO, and its density is only 0.035 g/cm. The impedance matching of the N-doped-rGO/g-CN composite was well adjusted by decreasing the dielectric constant and attenuation constant due to the g-CN semiconductor property and the graphite-like structure. Moreover, the distribution of g-CN among N-doped-rGO sheets can produce more polarization effect and relaxation effect by increasing the lamellar spacing. Furthermore, the polarization loss of N-doped-rGO/g-CN could be increased successfully by doping N atoms and g-CN. Ultimately, the MA property of N-doped-rGO/g-CN composite was optimized significantly, with a loading of 5 wt%, the N-doped-rGO/g-CN composite exhibited the RL of -49.59 dB and the effective absorption bandwidth could reach 4.56 GHz when the thickness was only 1.6 mm. The "thin thickness", "lightweight", "wide absorption bandwidth" and "strong absorption" of MA material are actually achieved by the N-doped-rGO/g-CN.