Core-Shell CoNi@Graphitic Carbon Decorated on B,N-Codoped Hollow Carbon Polyhedrons toward Lightweight and High-Efficiency Microwave Attenuation
Core-Shell CoNi@Graphitic Carbon Decorated on B,N-Codoped Hollow Carbon Polyhedrons toward Lightweight and High-Efficiency Microwave Attenuation
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DOI：
10.1021/acsami.9b08525
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发表时间：
2019-07-17
影响因子：
9.5
通讯作者：
Luo, Juhua
中科院分区：
文献类型：
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作者：
Liu, Panbo;Gao, Sai;Luo, Juhua
轻质和高效的微波衰减是碳基吸收剂开发中的两个主要挑战，这可以通过控制其化学成分，微观结构或阻抗匹配来同时实现。本工作以金属有机骨架为前驱体，通过简单的热分解过程，在B，N共掺杂的空心碳多面体上制备了核壳结构的CoNi@石墨碳。由Co-Ni-ZIF-67煅烧得到的B，N共掺杂空心碳多面体由碳纳米笼和BN畴组成，CoNi合金被石墨碳层包裹。当填充量为30wt%、厚度为3 mm时，吸波材料在7.2GHz处的RL最大值为-62.8dB，当厚度为2 mm时，-10dB以下的有效吸收带宽可达8 GHz。丰富的B-C-N杂原子之间的协同耦合效应、强偶极/界面极化、多重散射以及改善的阻抗匹配。该研究表明，共掺杂策略为合理设计具有轻质和上级微波衰减性能的碳基吸收剂提供了一种新的途径。
Lightweight and high-efficiency microwave attenuation are two major challenges in the exploration of carbon-based absorbers, which can be achieved simultaneously by manipulating their chemical composition, microstructure, or impedance matching. In this work, core-shell CoNi@graphitic carbon decorated on B,N-codoped hollow carbon polyhedrons has been constructed by a facile pyrolysis process using metal-organic frameworks as precursors. The B,N-codoped hollow carbon polyhedrons, originated from the calcination of Co-Ni-ZIF-67, are composed of carbon nanocages and BN domains, and CoNi alloy is encapsulated by graphitic carbon layers. With a filling loading of 30 wt %, the absorber exhibits a maximum RL of -62.8 dB at 7.2 GHz with 3 mm and the effective absorption bandwidth below -10 dB remarkably reaches as strong as 8 GHz when the thickness is only 2 mm. The outstanding microwave absorption performance stems from the hollow carbon polyhedrons and carbon nanocages with interior cavities, the synergistic coupling effect between the abundant B-C-N heteroatoms, the strong dipolar/interfacial polarizations, the multiple scatterings, and the improved impedance matching. This study demonstrates that the codoped strategy provides a new way for the rational design of carbon-based absorbers with lightweight and superior microwave attenuation.