Synthesis of AirRGO@FeCo hollow microspheres with strong microwave absorption properties

A kind of reduced graphene oxide hollow microspheres loaded with FeCo alloy (AirRGO@FeCo) was synthesized by oil-in-water emulsification technology and high-temperature calcination process. By controlling the concentration of GO aqueous solution, five kinds of hollow microspheres with different RGO contents were synthesized. The diameter of the synthesized hollow microspheres was 4–6 μm, and the thickness of the spherical wall was 0.1–1 μm adjustable. As the concentration of GO aqueous solution is 6 mg/ml, the AirRGO@FeCo exhibits excellent electromagnetic wave absorption properties with an optimal reflection loss value reaching up to − 73.47 dB at 13.75 GHz and a broad effective bandwidth (lower than − 10 dB) of 7.23 GHz (10.77 to 18 GHz) at a thickness of 2.4 mm. The synergistic effects of dielectric loss and magnetic loss mechanisms as well as excellent impedance matching characteristics and strong attenuation characteristics make AirRGO@FeCo hollow microspheres obtain high efficient microwave absorption capacity. Graphical abstract