Biomass-derived Magnetite/activated carbon nanocomposite as microwave absorber material

Porous carbon has been considered a high-performance microwave absorber, but its non-magnetic andrelatively poor matching property has limited its advanced applications. Carbon obtained frombiological materials was considered a dielectric material with a low weight to absorb electromagneticwaves. However, satisfactory absorption performance does not depend only on dielectric losses. Toobtain an excellent electromagnetic wave absorber, Fe۳O۴ magnetic nanoparticles have beensuccessfully decorated on the surface of porous carbon. Here, nanoporous biomass-derived activatedcarbon (AC) was prepared using Oleaster seeds. The prepared activated carbon showed excellentmicrowave absorption performance. Furthermore, to improve impedance matching, Fe۳O۴nanoparticles were decorated on the AC surface. The minimum reflection loss (RL) value of theprepared Fe۳O۴/AC composites could reach -۳۳.۲۹ dB at ۹.۶۷ GHz with a thin thickness of ۲ mm, andthe effective absorption bandwidth (RL<۱۰ dB) was ۳.۲۲ GHz when the thickness was ۲ mm.Compared to AC, the improved microwave absorption performance of Fe۳O۴/AC composites was dueto the improved impedance matching and the synergistic effect between dielectric and magnetic losses.The prepared Fe۳O۴/AC composites have great potential as efficient microwave material.

Keywords:

Reflection loss , Microwave absorption , Nanocomposite , Activated carbon