Carbon coated paramagnetic Fe₃O₄ nanoparticles decorated MWCNTs-GNS composites: synthesis, characterization and their excellent electromagnetic absorption properties

Carbon coated paramagnetic Fe₃O₄ nanoparticles decorated multi-wall carbon nanotubes (MWCNTs)—graphene (GNS) composites were synthesized. In addition, we studied the influence of the magnetic nanoparticle content on the absorbing properties. The results showed that the frequency corresponding to the maximum absorption shifted toward the lower frequency with the increase content of the magnetic nanoparticles. The results indicated that combination of graphene-MWCNTs with carbon coating and Fe₃O₄ nanoparticles can improve the impedance matching. In the composites, Fe₃O₄ nanoparticles improved the magnetic loss, and the graphene as well as the MWCNTs improved the dielectric loss. In addition, the presence of carbon coating enhanced the Debye dipole and dipole polarization, which enhanced the dielectric loss. The carbon coated paramagnetic Fe₃O₄ nanoparticles decorated MWCNTs-GNS composites that were composed of approximately 60% Fe₃O₄ nanoparticles showed the best electromagnetic absorption properties. The maximum reflection loss was − 57.13 dB at 6.1 GHz with a thickness of 3.4 mm.