Zeng Xiaojun, Nie Tianli, Zhao Chao, Gao Yanfeng, Liu Xiaofang
School of Materials Science and Engineering, Jingdezhen Ceramic University, Jingdezhen, 333403, China.
School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China.
Adv Sci (Weinh). 2024 Sep;11(35):e2403723. doi: 10.1002/advs.202403723. Epub 2024 Jul 16.
The excellent dielectric properties and tunable structural design of metal sulfides have attracted considerable interest in realizing electromagnetic wave (EMW) absorption. However, compared with traditional monometallic and bimetallic sulfides that are extensively studied, the unique physical characteristics of solid-solution-type sulfides in response to EMW have not been revealed yet. Herein, a unique method for preparing high-purity solid-solution-type sulfides is proposed based on solid-phase in situ exsolution of different metal ions from hybrid precursors. Utilizing CoAl-LDH/MIL-88A composite as a precursor, FeCoS single-phase nanoparticles are uniformly in situ formed on an amorphous substrate (denoted as CoAl), forming CoAl/FeCoS heterostructure. Combing with density functional theory (DFT) calculations and wave absorption simulations, it is revealed that FeCoS solid solution has stronger intracrystal polarization and electronic conductivity than traditional monometallic and bimetallic sulfides, which lead to higher dielectric properties in EM field. Therefore, CoAl/FeCoS heterostructure exhibits significantly enhanced EMW absorption ability in the low-frequency region (2-6 GHz) and can achieve frequency screening by selectively absorbing EMW of specific frequency. This work not only provides a unique method for preparing high-purity solid-solution-type sulfides but also fundamentally reveals the physical essence of their excellent EMW absorption performance.
金属硫化物优异的介电性能和可调控的结构设计在实现电磁波吸收方面引起了广泛关注。然而，与大量研究的传统单金属和双金属硫化物相比，固溶体型硫化物在响应电磁波方面的独特物理特性尚未被揭示。在此，基于从混合前驱体中不同金属离子的固相原位析出，提出了一种制备高纯度固溶体型硫化物的独特方法。以CoAl-LDH/MIL-88A复合材料为前驱体，FeCoS单相纳米颗粒均匀地原位形成在非晶衬底上（记为CoAl），形成CoAl/FeCoS异质结构。结合密度泛函理论（DFT）计算和吸波模拟，发现FeCoS固溶体比传统单金属和双金属硫化物具有更强的晶内极化和电子导电性，这导致其在电磁场中具有更高的介电性能。因此，CoAl/FeCoS异质结构在低频区域（2-6 GHz）表现出显著增强的电磁波吸收能力，并且可以通过选择性吸收特定频率的电磁波实现频率筛选。这项工作不仅为制备高纯度固溶体型硫化物提供了一种独特方法，而且从根本上揭示了其优异电磁波吸收性能的物理本质。
