GO@Fe₃O₄@CuSilicate Composite with a Hierarchical Structure: Fabrication, Microstructure, and Highly Electromagnetic Shielding Performance

Two nanocomposites with a hierarchical structure (GO@CuSilicate@Fe₃O₄ and GO@Fe₃O₄@CuSilicate) were fabricated in this paper. These as-synthesized nanocomposites were analyzed for their structural, compositional, and morphological features by X-ray diffraction, scanning electron microscopy (SEM), Raman spectroscopy, and Brunauer-Emmett-Teller methods. SEM images showed that both nanocomposites had a core-shell structure, and their shells were composed of CuSilicate nanoneedle arrays. Further, their total electromagnetic shielding efficiency was measured and compared in a wide frequency range of 8-12 GHz (X-band). Because of the "antenna" role of CuSilicate nanoneedle arrays and the polarization at the interface between graphene oxide (GO) and Fe₃O₄, GO@Fe₃O₄@CuSilicate showed higher electromagnetic shielding performance than that of GO@CuSilicate@Fe₃O₄. With 1 mm thickness, GO@Fe₃O₄@CuSilicate showed a high electromagnetic shielding efficiency (over 40 dB) in the whole X-band (8.2-12.4 GHz) and reached a maximum value (41.8 dB) at 8.2 GHz. Its total electromagnetic shielding efficiency was mainly contributed by absorption rather than reflection. This study provided an idea for the structural design of high-performance electromagnetic shielding materials in the GHz frequency range (X band).