Flower-like hierarchical Fe3O4-based heterostructured microspheres enabling superior electromagnetic wave absorption

Rational design of hierarchical heterogeneous structured Fe3O4 toward boosted electromagnetic wave absorption (EMA) is extremely imperative and needs further exploration. In this study, we use two types of dielectric components, including TiO2 and SiO2 particles, as intercalations anchor in Fe3O4 micro-flower framework through a sol–gel process to construct hierarchical hetero-structures. The tunable contents of anchoring particles allow the composites to retain their micro-flower structure and enable a reinforced polarization loss as well as enhanced impedance matching. Accordingly, both Fe3O4/TiO2 and Fe3O4/SiO2 exhibit improved EMA performance. In detail, Ti-2 possesses an absorption bandwidth of 7.3 GHz (9.3–16.6 GHz) under 2.0 mm and a reflection loss (RL) of −67.1 dB under 3.78 mm. Si-2 exhibits strong absorption with RL of −59.1 dB under 2.35 mm and absorption bandwidth of 4.8 GHz (8.3–13.1 GHz) under 2.0 mm. More importantly, an in-depth analysis confirms that the EMA of Ti-2 is superior to the previously reported results in terms of absorption bandwidth, matching thickness, and absorption intensity. Therefore, this work provides a novel pathway to fabricate high-performance EMA absorbers via rational design of hierarchical hetero-structure.