Electromagnetic wave absorption property of crosslinked holey Fe/FeO/Fe₂O₃/RGO nanocomposite

Integrating graphene with magnetic materials that possess tailored morphologies, structures, and abundant heterointerfaces is an effective strategy for optimizing electromagnetic (EM) wave absorption performance. Here, a straightforward three-step method for synthesizing holey Fe/FeO/Fe₂O₃ nanosheet (FO)/reduced graphene oxide (FORGO) nanocomposites as high-performance EM wave absorbers was presented. The process involves anchoring holey Fe/FeO/Fe₂O₃ nanosheets onto reduced graphene oxide (RGO) and forming crosslinking structures between the holey nanosheets and RGO as the graphene oxide (GO) concentration exceeds 3 mg ml⁻¹. By adjusting the FO/RGO ratio, both EM wave absorption performance and impedance matching can be effectively tuned. FORGO4 achieves a maximum reflection loss of −28.17 dB and an effective bandwidth (below −10 dB) of 4.10 GHz at a thickness of 2.18 mm. Leveraging the unique morphology and structure, along with the dielectric and magnetic components, a multifaceted synergistic mechanism—encompassing multiple reflection/scattering, interface polarization, dipole polarization, conductive loss, eddy current loss, exchange resonance, and optimal impedance matching—is demonstrated in the EM wave dissipation processes. Additionally, the significant contribution of multiple interface polarizations triggered by heterointerfaces to EM wave attenuation is noted. However, quantifying the contribution of interface polarization remains challenging. Density functional theory (DFT) simulations based on first principles are employed to verify the interface polarization.