High-performance EMI shielding effectiveness of Fe3O4-3D rPC nanocomposites: a systematic optimization in the X-band region

In this work, the microwave absorption (MWA) performance of a Fe3O4-3D reduced porous carbon nanocomposite (3D rPC NC) in the X-band region is reported. Three different shields are fabricated by altering the ratio of Fe3O4 nanoparticles (NPs) and 3D rPC and evaluating their microwave (MW) shielding performance with appropriate in-wearing instruments due to their minimum thickness. The chemical interaction between Fe3O4 NPs and 3D rPC is examined from chemical composition analysis of Fe3O4-3D rPC (1 : 2 ratio), which is confirmed by the presence of the Fe-O-C bond in the O 1s spectrum obtained from XPS analysis and subsequent analysis using FESEM images. Furthermore, it is found from N2 adsorption/desorption analysis that 3D rPC possesses a huge surface area of 787.312 m2 g-1 and showcases a type-V isotherm (mesoporous and/or microporous) behavior. The dielectric and magnetic losses of Fe3O4-3D rPC with a 1 : 2 ratio (tan δεr = 1.27 and tan δμr = 5.03) are higher than those of Fe3O4 NPs, 3D rPC and their NCs due to its magnetic and electrical conducting pathways modifying the material's polarization and dipole moment. The lightweight, polymer-free Fe3O4-3D rPC (1 : 2) NCs with minimum thickness on the order of 0.5 mm exhibited a higher total shielding effectiveness (SET = 41.285 dB), and it effectively blocked 99.9963% of the transmittance due to electric and magnetic polarization resulting from the presence of a heterogeneous interface surface.