Construction of flower-like core-shell Fe3O4@2H-MoS2 heterostructures: Boosting the interfacial polarization for high-performance microwave absorption

Abstract

Optimizing impedance matching and boosting interfacial polarization by constructing hierarchical magnetic/dielectric heterostructures is a promising strategy to acquire high-performance microwave absorption. Herein, 3D flower-like core-shell Fe3O4@2H-MoS2 architectures were constructed, in which magnetic Fe3O4 submicrospheres are uniformly coated by 2H-MoS2 nanosheets. Compared to bare Fe3O4 and 2H-MoS2, the hierarchical Fe3O4@2H-MoS2 heterostructures show boosting microwave absorption, which is related to the content of Fe3O4 submicrospheres. When the thickness is only 1.9 mm, the Fe3O4@2H-MoS2 heterostructures display an optimal reflection loss (RL) of −50 dB at 13.2 GHz and effective absorption bandwidth (EAB, RL ≤ −10 dB) of 4.2 GHz (11.4–15.6 GHz). Besides, an EAB can be achieved in 14.6–18.0 GHz with an ultrathin thickness of 1.5 mm. The superior microwave absorption of Fe3O4@2H-MoS2 heterostructures is mainly originated from two aspects. First, the combination of magnetic Fe3O4 and semi-conducting 2H-MoS2 can induce better impedance matching in comparison with the bare Fe3O4 and 2H-MoS2. Second, the embedded Fe3O4 core can greatly boost the complex permittivity and dielectric loss of 2H-MoS2, leading to improved microwave attenuation capacity. The boosting dielectric loss is primarily due to the unique interfacial polarization, induced by the special core-shell hierarchical architectures. This work suggests that optimizing impedance matching and boosting interfacial polarization are effective strategies to improve the microwave absorption of 2H-MoS2, which can be realized by loading magnetic nanostructures and designing 3D hierarchical heterostructures.