Lightweight and nitrogen-doped graphene nanoribbons with tunable hierarchical structure for high performance electromagnetic wave absorption

Nitrogen-doped graphene nanoribbons (NGNRs) have been prepared through a facile hydrothermal method with controllable graphene oxide nanoribbons (GONRs) and urea as precursors. The electromagnetic wave (EMW) parameters of NGNRs can be effectively regulated by controlling the oxidation of GONRs and the content of N atoms doping, which are favorable for impedance match and absorption. Benefiting from the controllable oxidation of GONRs, the NGNRs have hierarchical structure of 1D nanotubes and 2D nanoribbons, which can enhance the interaction between the NGNRs and EMW. At the thickness of 3 mm, 7NGNRs obtains a minimum reflection loss value of - 45 dB at 9 GHz, with an effective absorption bandwidth up to 3.2 GHz (from 7.5 to 10.7 GHz). The suitable microwave absorption performance of NGNRs is attributed to the abundant interfaces, N atoms and residual defects in NGNRs, which can not only benefit considerable impedance match but also act as polarization centers. This research provides an effective strategy to tune the EMW absorption performance of carbon-based materials for lightweight, wide-bandwidth absorbers with superior absorption properties.