Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
ACS Nano. 2012 Aug 28;6(8):6912-21. doi: 10.1021/nn3018443. Epub 2012 Jul 20.
Nitrogen doping of carbon nanotubes during chemical vapor deposition synthesis can create unique stacked cup-shaped structures termed as nitrogen-doped carbon nanotube cups (NCNCs). These cups have semielliptical hollow cavities and elevated reactivity which could lead to various applications. In this work, by applying intense ultrasonication to the as-synthesized NCNCs, we demonstrated an effective mechanical method to isolate the individual cups with opened cavities from their stacks. The graphitic structures of the isolated cups and their inherent nitrogen functionalities were characterized by comprehensive microscopic and spectroscopic methods. In particular, we quantitatively determined the existence of amine functionalities on NCNCs and found that they were preferentially distributed at the open edges of the cups, providing localized reactive sites. Further, by thiolating the amine groups with 3-mercapto-propionic acid, we were able to effectively cork the isolated cups by gold nanoparticles with commensurate diameters. These cup-shaped carbon nanomaterials with controlled inner volumes and gold nanoparticle corks could find potential applications as nanoscale reaction containers or drug delivery vehicles.
在化学气相沉积合成过程中对碳纳米管进行氮掺杂可以产生独特的堆叠杯状结构，称为氮掺杂碳纳米管杯（NCNC）。这些杯子具有半椭圆形的空心腔和升高的反应性，这可能导致各种应用。在这项工作中，通过对合成的 NCNC 施加强烈的超声处理，我们展示了一种有效的机械方法，从其堆叠中分离出具有开口腔的单个杯子。通过综合的微观和光谱方法对分离的杯子的石墨结构及其固有氮官能团进行了表征。特别是，我们定量确定了 NCNC 上存在胺官能团，并发现它们优先分布在杯子的开口边缘，提供了局部反应位点。此外，通过用 3-巯基丙酸对胺基团进行硫醇化，我们能够用相应直径的金纳米粒子有效地堵塞分离的杯子。这些具有可控内部体积和金纳米粒子塞子的杯状碳纳米材料可以作为纳米级反应容器或药物输送载体找到潜在的应用。
