3-D hierarchical urchin-like Fe₃O₄/CNTs architectures enable efficient electromagnetic microwave absorption

Three-dimensional (3-D) hierarchical urchin-like Fe₃O₄/CNTs architecture was synthesized through a simple one-pot hydrothermal method. The urchin-like Fe₃O₄ was assembled from a large number of nanorods with a diameter of ∼10 nm and a length of ∼100 nm. The introduction of CNTs in urchin-like Fe₃O₄ greatly improves the dielectric properties and impedance matching of architecture. The as-synthesized Fe₃O₄/CNTs architecture delivered excellent EMW absorption properties with a reflection loss (R_L) of −56.8 dB at 11.12 GHz and a thin thickness of 2.15 mm. The excellent EMW absorption performance of hierarchical Fe₃O₄/CNTs architecture may be attributed to the synergistic effect of interfacial polarization, conduction loss, eddy current loss, natural resonance, and multiple reflection/scattering. This study paves a robust strategy of 3-D hierarchical structure design to effectively enhance the EMW absorption performance of magnetic carbon composite.