Facile fabrication of ultra-light N-doped-rGO/g-C₃N₄ 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-C₃N₄ MA material was prepared for the first time by simple heat treatment, which the N atoms were doped into rGO and g-C₃N₄ was dispersed on the surface of N-doped-rGO, and its density is only 0.035 g/cm³. The impedance matching of the N-doped-rGO/g-C₃N₄ composite was well adjusted by decreasing the dielectric constant and attenuation constant due to the g-C₃N₄ semiconductor property and the graphite-like structure. Moreover, the distribution of g-C₃N₄ 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-C₃N₄ could be increased successfully by doping N atoms and g-C₃N₄. Ultimately, the MA property of N-doped-rGO/g-C₃N₄ composite was optimized significantly, with a loading of 5 wt%, the N-doped-rGO/g-C₃N₄ composite exhibited the RL_min 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-C₃N₄.