Synthesis of Hierarchical ZnFe₂O₄@SiO₂@RGO Core-Shell Microspheres for Enhanced Electromagnetic Wave Absorption

Hierarchical structured ZnFe₂O₄@SiO₂@RGO core-shell nanocomposites were prepared via a "coating-coating" route, and its structure, composition and electromagnetic properties were characterized. Compared with the binary composites of ZnFe₂O₄@SiO₂, the hierarchical ZnFe₂O₄@SiO₂@RGO ternary composites exhibited enhanced electromagnetic wave (EMW) absorption properties in terms of the effective bandwidth and minimum reflection loss (RL). Furthermore, EMW absorption properties of the prepared samples can be tuned by changing RGO content and thickness of SiO₂ layer to reach the best impedance match. The minimum RL of the sample with a thickness of 2.8 mm can reach -43.9 dB at 13.9 GHz, and its effective bandwidth (RL ≤ -10 dB) was up to 6 GHz. Hence, the obtained products can be a new candidate for lightweight EMW absorbing materials.