Facile Synthesis of Hollow Zn_xFe_{3- x}O₄@Porous MnO₂/rGO Conductive Network Composites for Tunable Electromagnetic Wave Absorption

To overcome the defects of weak impedance matching and low attenuation of electromagnetic wave absorption materials, we herein report hollow Zn_xFe_3-xO₄@porous MnO₂/rGO conductive network composites synthesized by some facile reactions. The special three-in-one structure of hollow, core-shell, and porous is sufficiently conducive to the absorption of electromagnetic wave by composites. Compared with binary hollow Zn_xFe_3-xO₄@porous MnO₂ and rGO/hollow Zn_xFe_3-xO₄ composites, the ternary composites show excellent electromagnetic wave absorption performance in both reflection loss and bandwidth. The maximum reflection loss of ∼50.6 dB occurs at 8.96 GHz and effective bandwidth below ∼10 dB (90% attenuation of electromagnetic wave) can shift from 3.6 to 18.0 GHz with a thickness of 1.5-5.5 mm. The superior absorption properties mostly derive from synergistic effect of magnetic and dielectric loss. These results endow rGO/hollow Zn_xFe_3-xO₄@porous MnO₂ composites with potential application in various fields of military radar, electronic communication, weaponry, and aerospace.