Wang Lei, Bai Xiaoyu, Zhao Ting, Lin Ying
School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an 710021, PR China.
School of Materials Science and Engineering, Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic Materials, Shaanxi University of Science and Technology, Xi'an 710021, PR China.
J Colloid Interface Sci. 2020 Nov 15;580:126-134. doi: 10.1016/j.jcis.2020.07.025. Epub 2020 Jul 9.
Manufacturing highly efficient microwave absorbents with powerful absorbing intensity, wide effective absorption bandwidth (RL < -10 dB, it means that 90% of the electromagnetic waves enter the absorber and are dissipated) and light weight at low filling loading is still a challenge. In this work, N, S-codoped honeycomb-like C/NiS composites were synthesized via a freeze-drying approach and following pyrolysis process under Ar atmosphere, using NaCl and sucrose as template and carbon source, respectively. When evaluated as a microwave absorbent, the as-obtained N, S-codoped honeycomb-like C/NiS composite pyrolyzed at 700 °C displayed high performance for microwave absorption including high absorption intensity (the maximum reflection loss of -46.8 dB at 13.4 GHz), broad effective absorbing bandwidth (7.0 GHz, 11.0-18.0 GHz) and relative low filling loading in paraffin (only 10 wt%). Such high performance of microwave absorption could be ascribed to the better impedance matching and stronger damping ability induced by unique honeycomb-like structure and suitable pyrolysis temperature. Importantly, our research might provide a facile and engineering strategy to explore other types of microwave absorbing materials to boost their microwave absorption at low filler loading.
制造具有强大吸收强度、宽有效吸收带宽（RL < -10 dB，这意味着90%的电磁波进入吸收体并耗散）且在低填充量下重量轻的高效微波吸收剂仍然是一个挑战。在这项工作中，以NaCl和蔗糖分别作为模板和碳源，通过冷冻干燥法并随后在Ar气氛下进行热解过程，合成了N、S共掺杂的蜂窝状C/NiS复合材料。当作为微波吸收剂进行评估时，在700°C热解得到的N、S共掺杂蜂窝状C/NiS复合材料表现出优异的微波吸收性能，包括高吸收强度（在13.4 GHz时最大反射损耗为-46.8 dB）、宽有效吸收带宽（7.0 GHz，11.0 - 18.0 GHz）以及在石蜡中的相对低填充量（仅10 wt%）。这种优异的微波吸收性能可归因于独特的蜂窝状结构和合适的热解温度所导致的更好的阻抗匹配和更强的阻尼能力。重要的是，我们 的研究可能为探索其他类型的微波吸收材料提供一种简便的工程策略，以在低填料负载下提高它们的微波吸收性能。
