Li Meifen, Liu Weiwei, Zhang Haixia, Liang Zhilu, Duan Pei, Yan Xiaoli, Guan Pengfei, Xu Bingshe, Guo Junjie
Innovative Center for Advanced Materials, Hangzhou Dianzi University, Hangzhou 310012, P. R. China.
Phys Chem Chem Phys. 2018 Jan 17;20(3):2022-2027. doi: 10.1039/c7cp07063b.
The violent reaction processing and required high-temperature environment involved in growing carbon onions make it difficult to obtain an insight into their evolution mechanism. By using deionized water as the medium of arc discharge, we successfully froze the synthetic reaction at intermediary stages and observed detailed structures of the obtained intermediates of carbon onions. Here we present the atomic-scale scanning transmission electron microscopy investigation of carbon onions produced by arc discharge in water. We directly observed that carbon onions at intermediary growth stage are characterized by unclosed few-layer graphene shells. Meanwhile, a kind of graphene flakes composed of 3 layers or less were also observed in the sample. The kindred evolution linkage was induced to exist among these few-layer graphene flakes and carbon onions in the arc discharge synthetic process. On the basis of microscopy observations, we propose that carbon onions are constructed by curling few-layer graphene flakes, which is beneficial for structural designs and controls of related carbon materials used in different fields.
生长碳洋葱所涉及的剧烈反应过程以及所需的高温环境使得深入了解其演化机制变得困难。通过使用去离子水作为电弧放电的介质，我们成功地将合成反应冻结在中间阶段，并观察到了所获得的碳洋葱中间体的详细结构。在此，我们展示了对水中电弧放电产生的碳洋葱进行的原子尺度扫描透射电子显微镜研究。我们直接观察到，中间生长阶段的碳洋葱的特征是未封闭的少层石墨烯壳。同时，在样品中还观察到了一种由三层或更少层组成的石墨烯薄片。在电弧放电合成过程中，这些少层石墨烯薄片和碳洋葱之间存在着类似的演化联系。基于显微镜观察结果，我们提出碳洋葱是由卷曲的少层石墨烯薄片构成的，这有利于不同领域相关碳材料的结构设计和控制。
