Technical Institute of Physics and Chemistry, Chinese Academy of Sciences , Beijing 100190, China.
College of Aerospace Engineering, Chongqing University , Chongqing 400044, China.
ACS Appl Mater Interfaces. 2017 Jan 25;9(3):2973-2983. doi: 10.1021/acsami.6b13142. Epub 2017 Jan 9.
It is well accepted that the microwave absorption performance (MAP) of carbon nanotubes (CNTs) can be enhanced via coating magnetic nanoparticles on their surfaces. However, it is still unclear if the magnetic coating structure has a significant influence on the microwave absorption behavior. In this work, nano-FeO compact-coated CNTs (FCCs) and FeO loose-coated CNTs (FLCs) are prepared using a simple solvothermal method. The MAP of the FeO-coated CNTs is shown to be adjustable via controlling the FeO nanocoating structure. The results reveal that the overall MAP of coated CNTs strongly depends on the magnetic coating structure. In addition, the FCCs show a much better MAP than the FLCs. It is shown that the microwave absorption difference between the FLCs and FCCs is due to the disparate complementarities between the dielectric loss and the magnetic loss, which are related to the coverage density of FeO nanoparticles on the surfaces of CNTs. For FCCs, the mass ratio of CNTs to Fe is then optimized to maximize the effective complementarities between the dielectric loss and the magnetic loss. Finally, a comparison is made with the literature on FeO-carbon-based composites. The FCCs at the optimized CNT to Fe ratio in the present work show the most effective specific RL (28.7 dB·mm) and the widest effective bandwidth (RL < -10 dB) (8.3 GHz). The excellent MAP of the as-prepared FCC sample is demonstrated to result from the consequent dielectric relaxation process and the improved magnetic loss. Consequently, the structure-property relationship revealed is significant for the design and preparation of CNT-based materials with effective microwave absorption.
人们普遍认为，通过在碳纳米管（CNTs）表面涂覆磁性纳米粒子，可以提高其微波吸收性能（MAP）。然而，目前尚不清楚磁性涂层结构对微波吸收行为是否有显著影响。在这项工作中，采用简单的溶剂热法制备了纳米 FeO 致密涂层 CNTs（FCCs）和 FeO 疏松涂层 CNTs（FLCs）。结果表明，通过控制 FeO 纳米涂层结构，可以调节 FeO 涂层 CNTs 的 MAP。结果表明，涂层 CNTs 的整体 MAP 强烈依赖于磁性涂层结构。此外，FCCs 的 MAP 明显优于 FLCs。研究表明，FLCs 和 FCCs 之间的微波吸收差异归因于介电损耗和磁损耗之间的互补性不同，这与 CNTs 表面上 FeO 纳米颗粒的覆盖密度有关。对于 FCCs，然后优化 CNT 与 Fe 的质量比，以最大限度地提高介电损耗和磁损耗之间的有效互补性。最后，与 FeO-碳基复合材料的文献进行了比较。在本工作中，优化 CNT 与 Fe 比的 FCCs 表现出最有效的特定 RL（28.7 dB·mm）和最宽的有效带宽（RL < -10 dB）（8.3 GHz）。所制备的 FCC 样品具有优异的 MAP，这归因于随后的介电弛豫过程和磁损耗的提高。因此，所揭示的结构-性能关系对于设计和制备具有有效微波吸收性能的 CNT 基材料具有重要意义。
