Porous CNTs/Co Composite Derived from Zeolitic Imidazolate Framework: A Lightweight, Ultrathin, and Highly Efficient Electromagnetic Wave Absorber
Porous CNTs/Co Composite Derived from Zeolitic Imidazolate Framework: A Lightweight, Ultrathin, and Highly Efficient Electromagnetic Wave Absorber
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DOI：
10.1021/acsami.6b12178
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发表时间：
2016-12-21
影响因子：
9.5
通讯作者：
Shui, Jianglan
中科院分区：
文献类型：
--
作者：
Yin, Yichao;Liu, Xiaofang;Shui, Jianglan
在还原气氛下，采用原位裂解法制备了十二面体形貌的多孔碳纳米管/钴纳米颗粒(CNTs/Co)复合材料。通过控制热解条件，可以很好地调节复合材料的形态和微观结构。在较低的热解温度下，碳纳米管/钴复合材料由分散良好的Co纳米颗粒和低石墨化程度的碳纳米管团簇组成。热解温度/时间的增加促进了碳纳米管的生长和石墨化，并导致了Co纳米颗粒的聚集。优化后的碳纳米管/钴复合材料具有较强的介电损耗和磁损耗，并具有良好的阻抗匹配性能。有趣的是，碳纳米管/钴复合材料表现出极强的电磁波吸收能力，最大反射损耗为-60.4分贝。更重要的是，吸波材料的匹配厚度只有1.81 mm，复合材料在基体中的填充量只有20wt%。碳纳米管的高效吸附与其良好的结构设计以及碳纳米管与钴纳米颗粒之间的协同作用密切相关。碳纳米管/钴复合材料具有优异的吸波性能和轻质超薄的厚度，在电磁波吸收领域具有潜在的应用前景。
Porous carbon nanotubes/cobalt nanoparticles (CNTs/Co) composite with dodecahedron morphology was synthesized by in situ pyrolysis of the Co-based zeolitic imidazolate framework in a reducing atmosphere. The morphology and microstructure of the composite can be well tuned by controlling the pyrolysis conditions. At lower pyrolysis temperature, the CNTs/Co composite is composed of well-dispersed Co nanoparticles and short CNT clusters with low graphitic degree. The increase of pyrolysis temperature/time promotes the growth and graphitization of CNTs and leads to the aggregation of Co nanoparticles. The optimized CNTs/Co composite exhibits strong dielectric and magnetic losses as well as a good impedance matching property. Interestingly, the CNTs/Co composite displays extremely strong electromagnetic wave absorption with a maximum reflection loss of -60.4 dB. More importantly, the matching thickness of the absorber is as thin as 1.81 mm, and the filler loading of composite in the matrix is only 20 wt %. The highly efficient absorption is closely related to the well-designed structure and the synergistic effect between CNTs and Co nanoparticles. The excellent absorbing performance together with lightweight and ultrathin thickness endows the CNTs/Co composite with the potential for application in the electromagnetic wave absorbing field.