Graphene-Fe₃O₄ nanohybrids: Synthesis and excellent electromagnetic absorption properties

Graphene (G)-Fe₃O₄ nanohybrids were fabricated by first depositing β-FeOOH crystals with diameter of 3-5 nm on the surface of the graphene sheets. After annealing under Ar flow, β-FeOOH nanocrystals were reduced to Fe₃O₄ nanoparticles by the graphene sheets, and thus G-Fe₃O₄ nanohybrids were obtained. The Fe₃O₄ nanoparticles with a diameter of about 25 nm were uniformly dispersed over the surface of the graphene sheets. Moreover, compared with other magnetic materials and the graphene, the nanohybrids exhibited significantly increased electromagnetic absorption properties owing to high surface areas, interfacial polarizations, and good separation of magnetic nanoparticles. The maximum reflection loss was up to -40.36 dB for G-Fe ₃O₄ nanohybrids with a thickness of 5.0 mm. The nanohybrids are very promising for lightweight and strong electromagnetic attenuation materials.