Facile synthesis and enhanced electromagnetic microwave absorption performance for porous core-shell Fe3O4@MnO2 composite microspheres with lightweight feature
Facile synthesis and enhanced electromagnetic microwave absorption performance for porous core-shell Fe3O4@MnO2 composite microspheres with lightweight feature
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DOI：
10.1016/j.jallcom.2016.09.181
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发表时间：
2017-02-05
影响因子：
6.2
通讯作者：
Zhang, Qiuyu
中科院分区：
文献类型：
--
作者：
Qiao, Mingtao;Lei, Xingfeng;Zhang, Qiuyu
采用两步水热法成功合成了以多孔Fe 3 O 4为核、MnO 2为壳的功能复合微球。采用X射线衍射法测定了样品的晶型。利用扫描电镜和透射电镜观察了Fe 3 O 4纳米粒子和Fe3O4@MnO2复合微球的形貌和微观结构。可以看出，分级结构的MnO 2壳具有包覆的Fe 3 O 4纳米颗粒，并且壳厚度约为140-160 nm。用N2吸附-脱附等温线测定了样品的比表面积和孔隙率，用振动样品磁强计测定了样品的磁性能。合成的Fe3O4@MnO2复合微球的BET比表面积为167 m2/g，孔径主要分布在介孔范围，尤其是2.0 ~ 12.0 nm。微波吸收性能研究表明，负载量为10%的Fe3O4@MnO2复合微球具有最强的RL峰，为-42.6dB（5.7 GHz），匹配厚度为4.0 mm，负载量为20%的Fe3O4@MnO2复合微球具有较宽的吸收带宽多孔核壳结构的Fe3O4@MnO2复合微球具有吸收强度高、有效吸收带宽宽、重量轻等优点，在微波吸收领域具有广阔的应用前景。(C)2016爱思唯尔B. V.保留所有权利。
Functional composite microspheres with porous Fe3O4 cores and hierarchical MnO2 shells have been synthesized successfully via a two-step hydrothermal method. X-ray diffraction was employed to determine the crystal forms of samples. The morphologies and microstructures of Fe3O4 nanoparticles and Fe3O4@MnO2 composite microspheres were observed by the scanning electron microscope and transmission electron microscope. It can be seen that hierarchically structured MnO2 shells have coated Fe3O4 nanoparticles, and the shell thickness is about 140-160 nm. The BET specific surface area and porosity were estimated by the N-2 absorption-desorption isotherms and the magnetic properties were measured by the vibrating sample magnetometer. As-synthesized Fe3O4@MnO2 composite microspheres have a BET specific surface area of 167 m(2)/g, and the pore width is mainly distributed in the mesoporous range, especially from 2.0 nm to 12.0 nm. Investigations of microwave absorbing properties manifest that Fe3O4@MnO2 composite microspheres with loading 10% weight fraction possess the strongest RL peak of -42.6 dB ( 5.7 GHz) at the matching thickness 4.0 mm, and Fe3O4@MnO2 composite microspheres with loading 20% weight fraction have a broader absorbing bandwidth ( 10.2-15.0 GHz and 15.5-17.3 GHz) at the matching thickness 1.5 mm. Achieving the advantages of intensive absorption, wide effective absorbing bandwidth band and intrinsic lightweight feature, porous core-shell Fe3O4@MnO2 composite microspheres are believed to be more promising in the application of microwave absorption. (C) 2016 Elsevier B.V. All rights reserved.