CoFeO nanoparticles decorated MoS-reduced graphene oxide nanocomposite for improved microwave absorption and shielding performance.

Magnetic CoFeO nanoparticles decorated onto the surface of a MoS-reduced graphene oxide (MoS-rGO/CoFeO) nanocomposite were synthesized by a simple two-step hydrothermal method. The electromagnetic (EM) wave absorption performance and electromagnetic interference (EMI) shielding effectiveness of the materials were examined in the frequency range of 8.0-12.0 GHz (X-band). The MoS-rGO/CoFeO nanocomposite was characterized by various tools such as X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. High-resolution transmission electron microscopy results confirmed the decoration of magnetic nanoparticles onto the surface of the MoS-rGO nanocomposite with a diameter of 8-12 nm. The multiple interfacial polarization, moderate impedance matching, and defect dipole polarization improve the dielectric and magnetic loss of the materials, which leads to strong attenuation loss ability of incident EM energy within the shield. The pure MoS-rGO nanocomposite represents total shielding effectiveness (SE ∼16.52 dB), while the MoS-rGO/CoFeO nanocomposite exhibits total shielding effectiveness (SE ∼19.26 dB) over the entire frequency range. It may be explained that the magnetic nanoparticles (CoFeO) serve as excellent conductive and magnetic fillers with a large surface area, leading to the migration of charge carriers at multi-interfaces.