Science and Technology on Thermostructural Composite Materials Laboratory, Northwestern Polytechnical University, Xi'an 710072, China.
DGUT-CNAM Institute, Dongguan University of Technology, Dongguan 523106, China.
ACS Appl Mater Interfaces. 2023 Jul 5;15(26):31720-31728. doi: 10.1021/acsami.3c04839. Epub 2023 Jun 25.
Electromagnetic (EM) wave absorbers at a lower-frequency region (2-8 GHz) require higher attenuation ability to achieve efficient absorption. However, the impedance match condition and attenuation ability are usually inversely related. Herein, one-dimensional hollow carbon nanofibers with graphene nanorods are prepared based on coaxial electrospinning technology. The morphology of graphene nanorods can be controlled by the annealing process. As the annealing time increased from 2 to 8 h, graphene nanospheres grew into graphene nanorods, which were catalyzed by Co catalysts derived from ZIF-67 nanoparticles. These nanorods can play the role of nano-antennas, which can guide EM waves into materials to enhance impedance match conditions. As a result, the carbon nanofibers with graphene nanorods possess a larger impedance match area with higher attenuation ability. The minimum reflection loss reaches -57.1 dB at a thickness of 4.6 mm, and the effective absorption bandwidth can cover almost both the S and C bands (2.4-8 GHz). This work contributes a meaningful perspective into the modulation of microwave absorption performance in the lower-frequency range.
在低频区域（2-8 GHz），电磁波吸收体需要更高的衰减能力才能实现高效吸收。然而，阻抗匹配条件和衰减能力通常是相反的。在此，我们通过同轴静电纺丝技术制备了具有石墨烯纳米棒的一维空心碳纳米纤维。通过退火过程可以控制石墨烯纳米棒的形态。随着退火时间从 2 小时增加到 8 小时，由 ZIF-67 纳米颗粒衍生的 Co 催化剂将石墨烯纳米球催化生长成石墨烯纳米棒。这些纳米棒可以起到纳米天线的作用，将电磁波引导入材料中，从而增强阻抗匹配条件。因此，具有石墨烯纳米棒的碳纳米纤维具有更大的阻抗匹配面积和更高的衰减能力。在厚度为 4.6 毫米时，最小反射损耗达到-57.1 dB，有效吸收带宽几乎覆盖了 S 波段和 C 波段（2.4-8 GHz）。这项工作为在较低频率范围内调制微波吸收性能提供了有意义的视角。
