Synthesis and microwave absorption enhancement of Fe-doped NiO@SiO2@graphene nanocomposites

Fe-doped NiO@SiO₂@graphene nanocomposites have been successfully fabricated for the first time, in which Fe-doped NiO nanoparticles are about 3 nm in diameter. In order to measure their electromagnetic properties, Fe-doped NiO@SiO₂@graphene (25 wt%) wax composites were then prepared. The experimental results show that Fe-doped NiO@SiO₂@graphene nanocomposites exhibit significantly enhanced microwave absorption performance in terms of both the maximum reflection loss value and the absorption bandwidth in comparison with NiO@SiO₂@graphene. The maximum reflection loss of Fe-doped NiO@SiO₂@graphene nanocomposites can reach −51.2 dB at 8.6 GHz with a thickness of 4 mm, and the absorption bandwidth with the reflection loss below −10 dB is 4 GHz (from 7 to 11 GHz). Therefore, this kind of nanocomposites may have the potential as high-efficient absorbers for microwave absorption applications.