Synthesis of core-shell FeCo@SiO_2 particles coated with the reduced graphene oxide as an efficient broadband electromagnetic wave absorber

摘要

The FeCo@SiO_2@RGO composites were prepared by combining liquid-phase reduction reaction in Argon atmosphere with hydrothermal reaction. The crystal structure, chemical composition and morphology of the as-prepared composites have been investigated in detail. SEM and TEM results illustrate that the FeCo@SiO_2 composites are of core-shell structure with a diameter of about 150-200 nm. Compared with FeCo@SiO_2 and FeCo@RGO composites, the as-prepared FeCo@SiO_2@RGO composites exhibit excellent electromagnetic (EM) wave absorption properties. As an EM wave absorber, the maximum R_L reaches −52.9 dB at 9.12 GHz with a thickness of 3.0 mm, and the absorption bandwidth with the reflection loss below −10 dB was up to 5.36 GHz (from 8.8 to 14.16 GHz) with a thickness of 2.5 mm. It is believed that the FeCo@SiO_2@RGO composites can serve as an excellent microwave absorbent and can be widely used in the microwave absorbing area.