Department of Mechanical Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
Nanoscale. 2016 Aug 14;8(30):14523-9. doi: 10.1039/c6nr02749k. Epub 2016 Jul 14.
Synthesis of single-walled carbon nanotubes (SWNTs) with well-defined atomic arrangements has been widely recognized in the past few decades as the biggest challenge in the SWNT community, and has become a bottleneck for the application of SWNTs in nano-electronics. Here, we report a selective synthesis of (12, 6) SWNTs with an enrichment of 50%-70% by chemical vapor deposition (CVD) using sputtered Co-W as a catalyst. This is achieved under much milder reduction and growth conditions than those in the previous report using transition-metal molecule clusters as catalyst precursors (Nature, 2014, 510, 522). Meanwhile, in-plane transmission electron microscopy unambiguously identified an intermediate structure of Co6W6C, which is strongly associated with selective growth. However, most of the W atoms disappear after a 5 min CVD growth, which implies that anchoring W may be important in this puzzling Co-W system.
在过去的几十年中，人们广泛认识到，具有明确原子排列的单壁碳纳米管（SWNTs）的合成是 SWNTs 领域面临的最大挑战，并且已经成为 SWNTs 在纳米电子学中应用的瓶颈。在这里，我们通过化学气相沉积（CVD）报告了使用溅射 Co-W 作为催化剂的（12,6）SWNTs 的选择性合成，其富集度为 50%-70%。与以前使用过渡金属分子簇作为催化剂前体的报告相比，这是在更温和的还原和生长条件下实现的（《自然》，2014 年，510,522）。同时，面内透射电子显微镜明确地鉴定了与选择性生长密切相关的 Co6W6C 中间结构。然而，在 5 分钟的 CVD 生长后，大部分 W 原子消失，这意味着在这个令人困惑的 Co-W 体系中，锚定 W 可能很重要。
