Enhancing the Electromagnetic Performance of Co through the Phase-Controlled Synthesis of Hexagonal and Cubic Co Nanocrystals Grown on Graphene
Enhancing the Electromagnetic Performance of Co through the Phase-Controlled Synthesis of Hexagonal and Cubic Co Nanocrystals Grown on Graphene
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通过相控合成在石墨烯上生长的六方和立方钴纳米晶体来增强钴的电磁性能
DOI：
10.1021/am404117v
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发表时间：
2013-12-11
影响因子：
9.5
通讯作者：
Yang, Xiaojing
中科院分区：
文献类型：
--
作者：
Pan, Guohua;Zhu, Jia;Yang, Xiaojing
钴是一种很有前途的软金属磁性材料，在吸波隐身技术，特别是吸收厘米波方面有着重要的应用。然而，由于其不稳定性、聚集性和结晶形式，它经常呈现弱介电性质。发展了一种通过在石墨烯（GN）网络上相控合成Co纳米结构来提高金属Co电磁性能的方法。通过一步液相法，在不同的反应条件下，将片状氧化石墨（GO）还原成沿着Co纳米晶的同时，成功地在GN纳米片上组装了尺寸均匀、分散性好的面心立方钴（β-Co）纳米球和面心立方钴（α-Co）纳米晶.与相应的Co纳米晶或GN相比，Co/GN纳米复合材料表现出优异的微波吸收性能，尤其是GN与α-Co纳米晶的纳米复合材料（反射损耗在11.9 GHz时为-47.5 dB），这可能是因为十字架的特殊电性能，连接的GN纳米片和它们的微结构中的完美电磁匹配以及Co纳米晶体的小颗粒尺寸。该方法简便有效。由于其多功能性，一些磁性金属或合金材料也可以通过该路线制备。
Cobalt is a promising soft metallic magnetic material used for important applications in the field of absorbing stealth technology, especially for absorbing centimeter waves. However, it frequently presents a weak dielectric property because of its instability, aggregation, and crystallographic form. A method for enhancing the electromagnetic property of metal Co via phase-controlled synthesis of Co nanostructures grown on graphene (GN) networks has been developed. Hexagonal close-packed cobalt (alpha-Co) nanocrystals and face-centered cubic cobalt (beta-Co) nanospheres with uniform size and high dispersion have been successfully assembled on GN nanosheets via a facile one-step solution-phase strategy under different reaction conditions in which the exfoliated graphite oxide (graphene oxide, GO) nanosheets were reduced along with the formation of Co nanocrystals. The as-synthesized Co/GN nanocomposites showed excellent microwave absorbability in comparison with the corresponding Co nanocrystals or GN, especially for the nanocomposites of GN and alpha-Co nanocrystals (the reflection loss is -47.5 dB at 11.9 GHz), which was probably because of the special electrical properties of the cross-linked GN nanosheets and the perfect electromagnetic match in their microstructure as well as the small particle size of Co nanocrystals. The approach is convenient and effective. Some magnetic metal or alloy materials can also be prepared via this route because of its versatility.