Large Annular Dipoles Bounded between Single-Atom Co and Co Cluster for Clarifying Electromagnetic Wave Absorbing Mechanism

Hu Liu, Xueqian Li, Xiaoying Zhao, Min Zhang, Xinhua Liu, Shichun Yang, Hongjing Wu, Zhenhui Ma

科研成果: 期刊稿件文章同行评审

69 引用 (Scopus)

摘要

It is very challenging to demonstrate the intrinsic feature and absorption mechanism for electromagnetic (EM) wave absorber since dipole polarization loss is always discussed together with magnetic loss, conductive loss, defects/interfacial polarization, and so on. To address this issue, here, a kind of atomic composites is reported, including single-atom Co and Co cluster with controllable atom dipole to tune the polarization and establish the link between dipole polarization and the EM wave absorption. Using a chemical synthesis route, the atomic composites are fabricated, including Co single-atom (SA) sites and cluster (Cs) on nitrogen-doped graphitic carbon (Co1+Cs/NGC). Due to the special design, the effect of magnetic loss, conductive loss, and interfacial polarization on EM wave dissipation can be ignored so that it can only highlight dielectric loss caused by dipole polarization. And, by controlling the Co atoms concentration, it can tune the valence state of Co atoms between 0 to +2 to control dipole polarization and relaxation. As a result, the Co1+Cs/NGC-2 with Co concentration of 6.0 wt% exhibits optimized dipole moments and thus excellent absorption performance (the reflection loss exceeds −54.3 dB, and the effective absorption bandwidth with RL ≤−10 dB reaches 7.0 GHz at 2.0 mm) due to the effective dipole polarization caused by the large annular dipole bounded between Co SA sites and Co Cs. This study proposes a simplified model to clarify EM wave absorption mechanism from atom view.

源语言英语
文章编号2304442
期刊Advanced Functional Materials
33
40
DOI
出版状态已出版 - 2 10月 2023

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