A Simple Road for the Transformation of Few-Layer Graphene into MWNTs
A Simple Road for the Transformation of Few-Layer Graphene into MWNTs
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DOI：
10.1021/ja303131j
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发表时间：
2012-08-15
影响因子：
15
通讯作者：
Prato, Maurizio
中科院分区：
文献类型：
--
作者：
Quintana, Mildred;Grzelczak, Marek;Prato, Maurizio
本文报道了在二甲基甲酰胺（DMF）中加入二茂铁醛（Fc-CHO）超声处理石墨，直接制备多壁碳纳米管（MWNT）。管状结构只出现在石墨烯层的边缘，并含有Fe簇。Pc与苯甲醛或其他Fc衍生物结合不会诱导NT的形成。向分散体中加入更高量的Fc-CHO不会显著增加MWNT形成。提高温度可以减少多壁碳纳米管的形成量，并显示出超声诱导的气穴能的关键作用。得出的结论是，Fc-CHO首先降低了自由基反应性物质的浓度，该自由基反应性物质将石墨烯切成小部分，将其自身定位在石墨烯的边缘，模板化片材的卷起以形成纳米卷，在那里它保持被捕获，并且最终接受未配对电子并将未配对电子捐赠到石墨烯边缘并将不太稳定的卷转化为MWNT。这种新方法与长期以来的观点相匹配，即CNT是石墨烯层。所提出的机制是通用的，并将导致通过简单的超声处理控制碳纳米结构的生产。
We report the direct formation of multiwalled carbon nanotubes (MWNT) by ultrasonication of graphite in dimethylformamide (DMF) upon addition of ferrocene aldehyde (Fc-CHO). The tubular structures appear exclusively at the edges of graphene layers and contain Fe clusters. Pc in conjunction with benzyl aldehyde, or other Fc derivatives, does not induce formation of NT. Higher amounts of Fc-CHO added to the dispersion do not increase significantly MWNT formation. Increasing the temperature reduces the amount of formation of MWNTs and shows the key role of ultrasound-induced cavitation energy. It is concluded that Fc-CHO first reduces the concentration of radical reactive species that slice graphene into small moieties, localizes itself at the edges of graphene, templates the rolling up of a sheet to form a nanoscroll, where it remains trapped, and finally accepts and donates unpaired electron to the graphene edges and converts the less stable scroll into a MWNT. This new methodology matches the long held notion that CNTs are rolled up graphene layers. The proposed mechanism is general and will lead to control the production of carbon nanostructures by simple ultrasonication treatments.