Li Yan-Sheng, Liao Jia-Liang, Wang Shan-Yu, Chiang Wei-Hung
Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, 10607, Taiwan.
Sci Rep. 2016 Mar 7;6:22755. doi: 10.1038/srep22755.
We have demonstrated an effective intercalation of multi-walled carbon nanotubes (MWCNTs) for the green and scalable synthesis of graphene nanoribbons (GNRs) using an intercalation-assisted longitudinal unzipping of MWCNTs. The key step is to introduce an intercalation treatment of raw MWCNTs with KNO3 and H2SO4, making it promising to decrease the strong van der Waals attractions in the MWCNTs bundles and between the coaxial graphene walls of CNTs. Systematic micro Raman, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) characterizations suggest that potassium, nitrate, and sulfate ions play an important role in the CNT intertube and intratube intercalations during the pretreatment. Detailed scanning electron microscopy (SEM), transmission electron microscopy, XRD, and micro Raman characterizations indicate that the developed methodology possesses the ability to synthesis GNRs effectively with an improved CNT concentration in H2SO4 of 10 mg/ml at 70 °C, which is amenable to industrial-scale production because of the decreased amount of strong acid. Our work provides a scientific understanding how to enhance the GNR formation by accelerating the CNT longitudinal unzipping via suitable molecular intercalation.
我们已经证明了通过多壁碳纳米管（MWCNTs）的插层辅助纵向解拉链作用，可实现多壁碳纳米管的有效插层，用于绿色且可扩展地合成石墨烯纳米带（GNRs）。关键步骤是用硝酸钾和硫酸对原始多壁碳纳米管进行插层处理，这有望降低多壁碳纳米管束内以及碳纳米管同轴石墨烯壁之间的强范德华吸引力。系统的显微拉曼光谱、X射线光电子能谱（XPS）和X射线衍射（XRD）表征表明，钾离子、硝酸根离子和硫酸根离子在预处理过程中对碳纳米管的管间和管内插层起着重要作用。详细的扫描电子显微镜（SEM）、透射电子显微镜、XRD和显微拉曼光谱表征表明，所开发的方法能够在70°C下，在硫酸中碳纳米管浓度提高到10 mg/ml的情况下有效地合成石墨烯纳米带，由于强酸用量减少，这适合工业规模生产。我们的工作为如何通过合适的分子插层加速碳纳米管纵向解拉链作用来增强石墨烯纳米带的形成提供了科学认识。
