Multifunctional Film Assembled from N-Doped Carbon Nanofiber with Co–N4–O Single Atoms for Highly Efficient Electromagnetic Energy Attenuation
Xu Jia, Bei Li, Zheng Ma, Xiao Zhang, Chunling Zhu, Feng Yan, Piaoping Yang, Yujin Chen
Abstract
Abstract Single-atom materials have demonstrated attractive physicochemical characteristics. However, understanding the relationships between the coordination environment of single atoms and their properties at the atomic level remains a considerable challenge. Herein, a facile water-assisted carbonization approach is developed to fabricate well-defined asymmetrically coordinated Co–N 4 –O sites on biomass-derived carbon nanofiber (Co–N 4 –O/NCF) for electromagnetic wave (EMW) absorption. In such nanofiber, one atomically dispersed Co site is coordinated with four N atoms in the graphene basal plane and one oxygen atom in the axial direction. In-depth experimental and theoretical studies reveal that the axial Co–O coordination breaks the charge distribution symmetry in the planar porphyrin-like Co–N 4 structure, leading to significantly enhanced dielectric polarization loss relevant to the planar Co–N 4 sites. Importantly, the film based on Co–N 4 –O/NCF exhibits light weight, flexibility, excellent mechanical properties, great thermal insulating feature, and excellent EMW absorption with a reflection loss of − 45.82 dB along with an effective absorption bandwidth of 4.8 GHz. The findings of this work offer insight into the relationships between the single-atom coordination environment and the dielectric performance, and the proposed strategy can be extended toward the engineering of asymmetrically coordinated single atoms for various applications.