Technology Research Association for Single Wall Carbon Nanotubes (TASC), Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan and National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1- Higashi, Tsukuba, Ibaraki 305-8565, Japan.
Department of Physics and Astronomy, Brigham Young University, Provo, Utah 84602, USA.
Nanoscale. 2016 Jan 7;8(1):162-71. doi: 10.1039/c5nr05537g.
We investigated the correlation between growth efficiency and structural parameters of single-walled carbon nanotube (SWCNT) forests and report the existence of a SWCNT "sweet spot" in the CNT diameter and spacing domain for highly efficient synthesis. Only within this region could SWCNTs be grown efficiently. Through the investigation of the growth rates for ∼340 CNT forests spanning diameters from 1.3 to 8.0 nm and average spacing from 5 to 80 nm, this "sweet spot" was found to exist because highly efficient growth was constrained by several mechanistic boundaries that either hindered the formation or reduced the growth rate of SWCNT forests. Specifically, with increased diameter SWCNTs transitioned to multiwalled CNTs (multiwall border), small diameter SWCNTs could only be grown at low growth rates (low efficiency border), sparse SWCNTs lacked the requirements to vertically align (lateral growth border), and high density catalysts could not be prepared (high catalyst density border). As a result, the SWCNTs synthesized within this "sweet spot" possessed a unique set of characteristics vital for the development applications, such as large diameter, long, aligned, defective, and high specific surface area.
我们研究了单壁碳纳米管（SWCNT）森林的生长效率与结构参数之间的相关性，并报告了 CNT 直径和间距域中存在 SWCNT“理想点”，在此区域内可以高效合成 SWCNT。只有在这个区域内，SWCNTs 才能被高效地生长。通过对约 340 个 CNT 森林的生长速率进行研究，这些 CNT 森林的直径范围从 1.3nm 到 8.0nm，平均间距范围从 5nm 到 80nm，发现了这个“理想点”的存在，因为高效生长受到几个机械边界的限制，这些边界要么阻碍了 SWCNT 森林的形成，要么降低了其生长速率。具体来说，随着直径的增加，SWCNTs 会过渡到多壁 CNT（多壁边界），小直径的 SWCNTs 只能以低生长速率生长（低效率边界），稀疏的 SWCNTs 缺乏垂直对齐的要求（横向生长边界），而高密度的催化剂无法制备（高密度催化剂边界）。因此，在这个“理想点”内合成的 SWCNTs 具有一组独特的特征，对其开发应用至关重要，如大直径、长、排列整齐、有缺陷和高比表面积。
