Facile Synthesis and Hierarchical Assembly of Flowerlike NiO Structures with Enhanced Dielectric and Microwave Absorption Properties
Facile Synthesis and Hierarchical Assembly of Flowerlike NiO Structures with Enhanced Dielectric and Microwave Absorption Properties
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具有增强介电和微波吸收性能的花状 NiO 结构的简便合成和分层组装
DOI：
10.1021/acsami.7b02597
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发表时间：
2017-05-17
影响因子：
9.5
通讯作者：
Kong, Ling Bing
中科院分区：
文献类型：
--
作者：
Liu, Peijiang;Ng, Vincent Ming Hong;Kong, Ling Bing
本文采用面水热法结合退火工艺合成了两种新型的花状NiO分级结构：玫瑰花（S1）和丝花（S2）。系统地研究了两种NiO结构的结构、形貌、磁性和电磁性能。SEM和TEM结果表明，Si具有直径在4-7 μ m范围内的分级玫瑰花结构，而S2表现出直径为0.7-1.0 μ m的多孔丝花结构。电磁性能测试表明，NiO的分级结构决定了其介电性能和阻抗匹配特性，进而影响其微波衰减性能。由于其分层和多孔结构，S2具有比Si更高的微波吸收性能。样品S2在13.9 GHz处的最大R-L值可达-65.1 dB，而有效带宽为3 GHz。此外，还对提高微波吸收率的机理进行了详细的讨论。本文所合成的NiO分级结构可作为设计新型微波吸收材料的参考。
In this work, two novel flowerlike NiO hierarchical structures, rose flower (S1) and silk-flower (S2), were synthesized by using a facial hydrothermal method, coupled with subsequent postannealing process. Structures, morphologies, and magnetic and electromagnetic properties of two NiO structures have been systematically investigated. SEM and TEM results suggested that Si had a hierarchical rose-flower architecture with diameters in the range of 4-7 mu m, whereas S2 exhibited a porous silk-flower architecture with diameters of 0.7-1.0 mu m. Electromagnetic performances indicated that the NiO hierarchical structures played a crucial role in determining their dielectric behavior and impedance matching characteristic, which further influenced the microwave attenuation property of absorbers based on them. Due to its hierarchical and porous architectures, S2 had higher microwave absorption performances than Si. The maximum R-L value for sample S2 can reach -65.1 dB at 13.9 GHz, while an efficient bandwidth of 3 GHz was obtained. In addition, the mechanism of the improved microwave absorption were discussed in detail. It is expected that our NiO hierarchical structures synthesized in this work could be used as a reference to design novel microwave absorption materials.