Coin-like α-Fe2O3@CoFe2O4 Core-Shell Composites with Excellent Electromagnetic Absorption Performance
Coin-like α-Fe2O3@CoFe2O4 Core-Shell Composites with Excellent Electromagnetic Absorption Performance
复制标题
具有优异电磁吸收性能的硬币状α-Fe2O3@CoFe2O4核壳复合材料
DOI：
10.1021/am508438s
复制
发表时间：
2015-03-04
影响因子：
9.5
通讯作者：
Du, Youwei
中科院分区：
文献类型：
--
作者：
Lv, Hualiang;Liang, Xiaohui;Du, Youwei
本文设计了一种新型的微波吸收核壳复合材料，其中α - fe2o3和多孔CoFe2O4纳米球分别作为核壳。有趣的是，在溶剂热过程中，PEG-200与蒸馏水的溶剂比(V)对α - fe2o3的形貌起着关键作用，当溶剂比为1:7、1:3和1:1时，α - fe2o3可以形成不规则片状、硬币状和更薄的硬币状。制备了直径70 nm的多孔CoFe2O4纳米球，作为α - fe2o3的壳层。值得注意的是，CoFe2O4涂层并没有破坏α - fe2o3的原始形状。与未包覆的α - fe2o3相比，Fe2O3@CoFe2O4复合材料在2-18 GHz的测试频率范围内具有更好的微波吸收性能。其中，片状复合材料的最佳反射损耗值在16.5 GHz时可达到-60 dB，涂层厚度仅为2 mm。RLmin值在-10 dB以下对应的频率带宽高达5 GHz （13-18 GHz）。复合材料的微波吸收性能的增强可能是由于这种特殊多孔核壳结构的强电子极化效应（即Fe和Co之间的电子极化）和电磁波散射作用所致。此外，α - fe2o3和CoFe2O4之间的协同效应也有利于电磁参数的平衡。我们的研究结果为制备吸收强度好、频率宽、重量轻的吸收剂提供了一条有希望的途径。
In this paper, we designed a novel core-shell composite for microwave absorption application in which the alpha-Fe2O3 and the porous CoFe2O4 nanospheres served as the core and shell, respectively. Interestingly, during the solvothermal process, the solvent ratio (V) of PEG-200 to distilled water played a key role in the morphology of alpha-Fe2O3 for which irregular flake, coin-like, and thinner coin-like forms of alpha-Fe2O3 can be produced with the ratios of 1:7, 1:3, and 1:1, respectively. The porous 70 nm diameter CoFe2O4 nanospheres were generated as the shell of alpha-Fe2O3. It should be noted that the CoFe2O4 coating layer did not damage the original shape of alpha-Fe2O3. As compared with the uncoated alpha-Fe2O3, the Fe2O3@CoFe2O4 composites exhibited improved microwave absorption performance over the tested frequency range (2-18 GHz). In particular, the optimal reflection loss value of the flake-like composite can reach -60 dB at 16.5 GHz with a thin coating thickness of 2 mm. Furthermore, the frequency bandwidth corresponding to the RLmin value below -10 dB was up to 5 GHz (13-18 GHz). The enhanced microwave absorption properties of these composites may originate from the strong electron polarization effect (i.e., the electron polarization between Fe and Co) and the electromagnetic wave scattering on this special porous core-shell structure. In addition, the synergy effect between alpha-Fe2O3 and CoFe2O4 also favored balancing the electromagnetic parameters. Our results provided a promising approach for preparing an absorbent with good absorption intensity and a broad frequency that was lightweight.