Synthesis of nitrogen-doped reduced graphene oxide/magnesium ferrite/polyaniline composite aerogel as a lightweight, broadband and efficient microwave absorber

The fabrication of graphene-based microwave absorbing materials with low density, small filling ratio, broad bandwidth and strong absorption remains a huge challenge. In this work, nitrogen-doped reduced graphene oxide/magnesium ferrite/polyaniline (NRGO/MgFe 2 O 4 /PANI) composite aerogel was synthesized by a three-step method of solvothermal reaction, in situ chemical oxidation polymerization and hydrothermal self-assembly. The results showed that the obtained aerogels had a unique three-dimensional (3D) porous network structure and low bulk density (11.1-13.0 mg cm -3 ). It was worth noting that in the NRGO/MgFe 2 O 4 /PANI ternary composite aerogel, MgFe 2 O 4 coated with a thin PANI layer was anchored on the surface of NRGO sheets. Furthermore, the NRGO/MgFe 2 O 4 /PANI ternary composite aerogel showed much better microwave absorbing capacity compared with pure NRGO aerogel and NRGO/MgFe 2 O 4 binary composite aerogel. When the filling ratio was as low as 11.5 wt.%, the obtained ternary composite aerogel exhibited the maximum effective absorption bandwidth of 7.0 GHz at a matching thickness of 2.1 mm, and the minimum reflection loss of -42.9 dB at a thickness of 3.57 mm. Additionally, the probable microwave dissipation mechanism was also elucidated. It was believed that this study would pave the way for the construction of 3D graphene-based composites as lightweight, broadband and efficient microwave absorbents. (c) 2023 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

In this work, a three-dimensional composite aerogel material composed of nitrogen-doped reduced graphene oxide, magnesium ferrite, and polyaniline was successfully synthesized. The aerogel exhibited low density, broad bandwidth, and strong absorption capacity. Compared with other materials, this composite aerogel showed better microwave absorbing performance and achieved the maximum absorption bandwidth at a low filling ratio.