Synthesis of nitrogen-doped graphene aerogels modified by magnetic Fe3O4/Fe/C frameworks as excellent dual-band electromagnetic absorbers

Abstract

Developing lightweight and high-performance electromagnetic wave (EMW) absorbing materials remains a huge challenge. In this work, a magnetic ferroferric oxide/iron/carbon framework decorated nitrogen-doped reduced graphene oxide (NRGO/Fe₃O₄/Fe/C) composite aerogel was prepared using a three-step route of solvothermal synthesis, pyrolysis treatment and hydrothermal self-assembly. The results of microscopic morphology analysis showed that the prepared NRGO/Fe₃O₄/Fe/C composite aerogel had a unique three-dimensional (3D) porous network structure, and lots of octahedral and loofah-like carbon frameworks were evenly distributed on the surface of the NRGO. Furthermore, the relationship between the microstructure and EMW absorption capacity of the NRGO/Fe₃O₄/Fe/C composite aerogel was studied. It is worth noting that when the filling ratio was as low as 15.0 wt%, the obtained quaternary composite aerogel exhibited the maximum effective absorption bandwidth of 7.92 GHz at a matching thickness of 2.34 mm (from 10.08 to 18.0 GHz, covering the partial X-band and full Ku-band), and the minimum reflection loss of −48.2 dB at a thickness of 3.01 mm. In addition, the results of the radar cross-section simulation demonstrated that the prepared composite aerogel had great potential for practical application. The excellent EMW dissipation ability of the NRGO/Fe₃O₄/Fe/C composite aerogel was mainly attributed to the reasonable structural design and multi-component synergy. It is believed that this study will contribute to the construction of 3D graphene-based composites as lightweight, broadband and efficient EMW absorbers.