Hierarchical Fe₃O₄@TiO₂ Yolk–Shell Microspheres with Enhanced Microwave‐Absorption Properties

Abstract

Abstract A facile and efficient strategy for the synthesis of hierarchical yolk–shell microspheres with magnetic Fe 3 O 4 cores and dielectric TiO 2 shells has been developed. Various Fe 3 O 4 @TiO 2 yolk–shell microspheres with different core sizes, interstitial void volumes, and shell thicknesses have been successfully synthesized by controlling the synthetic parameters. Moreover, the microwave absorption properties of these yolk–shell microspheres, such as the complex permittivity and permeability, were investigated. The electromagnetic data demonstrate that the as‐synthesized Fe 3 O 4 @TiO 2 yolk–shell microspheres exhibit significantly enhanced microwave absorption properties compared with pure Fe 3 O 4 and our previously reported Fe 3 O 4 @TiO 2 core–shell microspheres, which may result from the unique yolk–shell structure with a large surface area and high porosity, as well as synergistic effects between the functional Fe 3 O 4 cores and TiO 2 shells.