Key Laboratory of In-Fiber Integrated Optics, College of Physics and Optoelectronic Engineering, Harbin Engineering University, Harbin, 150001, China.
College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin, 150001, China.
Small. 2023 Jul;19(28):e2301226. doi: 10.1002/smll.202301226. Epub 2023 Mar 28.
The rational design of lightweight, broad-band, and high-performance microwave absorbers is urgently required for addressing electromagnetic pollution issue. Metal single atoms (M-SAs) absorbers receive considerable interest in the field of microwave absorption due to the unique electronic structures of M-SAs. However, the simultaneous engineering of the morphology and electronic structure of M-SAs based absorbers remains challenging. Herein, a template-assisted method is utilized to fabricate isolated Co-SAs on N-doped hollow carbon spheres (NHCS@Co-SAs) for high-performance microwave absorption. The combination of atomically dispersed Co sites and hollow supports endows NHCS@Co-SAs with excellent microwave absorption properties. Typically, at an ultralow filler content of 8 wt%, the minimum reflection loss and effective absorption bandwidth of the NHCS@Co-SAs are up to -44.96 dB and 5.25 GHz, respectively, while the absorbing thickness is only 2 mm. Theoretical calculations and experimental results indicate that the impedance matching characteristic and dielectric loss of the NHCSs can be tuned via the introduction of M-SAs, which are responsible for the excellent microwave absorption properties of NHCS@Co-SAs. This work provides an atomic-level insight into the relationship between the electronic states of absorbers and their microwave absorption properties for developing advanced microwave absorbers.
为了解决电磁污染问题，迫切需要设计出重量轻、带宽宽、性能高的微波吸收体。由于金属单原子（M-SAs）的独特电子结构，金属单原子吸收体在微波吸收领域受到了相当大的关注。然而，基于 M-SAs 的吸收体的形态和电子结构的同时工程仍然具有挑战性。在此，采用模板辅助法在 N 掺杂空心碳球（NHCS@Co-SAs）上制备孤立的 Co-SAs，以获得高性能的微波吸收体。原子分散的 Co 位和空心载体的结合赋予了 NHCS@Co-SAs 优异的微波吸收性能。通常，在超低的填充量 8wt%下，NHCS@Co-SAs 的最小反射损耗和有效吸收带宽可达-44.96dB 和 5.25GHz，而吸收层厚度仅为 2mm。理论计算和实验结果表明，通过引入 M-SAs 可以调节 NHCSs 的阻抗匹配特性和介电损耗，这是 NHCS@Co-SAs 具有优异的微波吸收性能的原因。这项工作为开发先进的微波吸收体提供了关于吸收体的电子态与其微波吸收性能之间关系的原子级见解。
