Mesoporous Fe/C and Core-Shell Fe-Fe3C@C composites as efficient microwave absorbents
Mesoporous Fe/C and Core-Shell Fe-Fe3C@C composites as efficient microwave absorbents
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DOI：
10.1016/j.micromeso.2015.02.054
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发表时间：
2015-07-15
影响因子：
5.2
通讯作者：
Xu, Yao
中科院分区：
文献类型：
--
作者：
Li, Guomin;Wang, Liancheng;Xu, Yao
通过Fe3+/酚醛树脂与F127的原位聚合和高温碳化，成功制备了介孔Fe/C和核壳Fe-Fe3C@C复合材料。实验涉及到含铁碳前驱体的制备和热处理过程。通过改变前驱体中Fe(NO3)(3)中心点9H(2)O的含量，可以得到两种形貌和结构不同的复合材料。研究了两种复合材料的晶相、结构和微波吸收特性。Fe颗粒均匀嵌入介孔网络，形成高比表面积467.3 m(2)/g、低密度1.92 g/cm(3)的介孔Fe/C复合材料。经石墨化碳层包裹的Fe-Fe3C颗粒形成了比表面积为259.5 m(2)/g、密度为2.67 g/cm(3)的核壳结构。Fe/C和Fe-Fe3C@C复合材料表现出优异的电磁吸收能力，有效吸收带宽分别达到336 GHz和5.04 GHz，匹配厚度分别为2和1.5 mm。这主要源于有效阻抗匹配和多次界面极化。此外，Fe3+的增加不仅促进了碳壳的石墨化程度，而且增加了核壳结构的复介电常数和磁导率，从而改善了阻抗匹配。介孔Fe/C和核壳Fe-Fe3C@C复合材料具有高表面积、低密度和优异的微波吸收性能，是轻质、高效的微波吸收材料。(C) 2015爱思唯尔公司版权所有。
Mesoporous Fe/C and core-shell Fe-Fe3C@C composites were successfully prepared through the in-situ polymerization of Fe3+/phenolic resin coupled with F127 and the subsequent high-temperature carbonization. The experiments involved the preparation of an iron-containing carbon precursor and the heat-treatment process. Two composites with different morphology and structure could be obtained by changing the content of Fe(NO3)(3)center dot 9H(2)O in the precursor. The crystalline phase, structure and microwave absorption of the two composites were investigated. Fe particles were uniformly embedded into the mesoporous networks to form mesoporous Fe/C composite with high surface area of 467.3 m(2)/g and low density of 1.92 g/cm(3). The Fe-Fe3C particles encapsulated by graphitized carbon layers formed the core shell structure with surface area and density of 259.5 m(2)/g and 2.67 g/cm(3). Fe/C and Fe-Fe3C@C composites exhibited excellent electromagnetic absorbing ability, the effective absorption bandwidth reached 336 and 5.04 GHz with the matching thicknesses of 2 and 1.5 mm correspondingly. This originated mainly from the effective impedance match and multiple interfacial polarizations. Furthermore, the increase of Fe3+ not only promoted the graphitization degree of carbon shell, but also increased the complex permittivity and permeability of core shell structure, thus improved the impedance matching. Owing to high surface area, low density and excellent microwave absorbability, the mesoporous Fe/C and core shell Fe-Fe3C@C composites are promising candidates as lightweight and high-efficiency microwave absorbents. (C) 2015 Elsevier Inc. All rights reserved.