Facile synthesis of yolk-shell pompon-like Fe@void@CeO2@Ni nanospheres with enhanced microwave absorption properties

Due to the multiple scattering of microwaves and the existence of electron aggregation polarization at heterogeneous interfaces, the design of hollow or anisotropic microstructures has always been one of the research focuses of microwave absorption materials (MAMs). In this work, an effective strategy has been proposed reasonably to manufacture yolk-shell pompon-like Fe@void@CeO 2 @Ni nanospheres via hydrogen reduction and multiple solvothermal procedures. The results show that the metallic iron core with a diameter of 300 nm and the outer CeO 2 layer with a thickness of 70 nm compound to form a yolk-shell structure, and the metallic nickel nanosheets with a length of about 100 nm are evenly embedded in the CeO 2 layer to form a pompon-like structure. These unique microstructures provide heterogeneous interfacial polarization, three-dimensional conductive networks, and multiple electromagnetic scattering which bring excellent dielectric loss to the composites. Combined with the inherent strong magnetic loss of magnetic metals, as-prepared composites exhibit excellent microwave absorption properties. The minimal RL value reaches −48.9 dB and the efficient absorption bandwidth reaches 14 GHz with the thickness ranges from 2.5 to 7 mm. Hence, this unique microstructural design scheme has great prospects in the field of MAMs.