Department of Chemistry and Institute for Advanced Research, Nagoya University, Nagoya, Japan.
Nanotechnology. 2011 Sep 30;22(39):395602. doi: 10.1088/0957-4484/22/39/395602. Epub 2011 Sep 2.
We report high purity and high yield synthesis of single-wall carbon nanotubes (SWCNTs) of narrow diameter from iron-copper bimetal catalysts. The SWCNTs with diameter of 0.8-1.2 nm are synthesized using the zeolite-supported alcohol chemical vapour deposition method. Single metal and bimetal catalysts are systematically investigated to achieve both the enhancement of SWCNT yield and the suppression of the undesired formation of graphitic impurities. The relative yield and purity of SWCNTs are quantified using optical absorption spectroscopy with an ultracentrifuge-based purification technique. For the single metal catalyst, iron shows the highest catalytic activity compared with the other metals such as cobalt, nickel, molybdenum, copper, and platinum. It has been found that the addition of copper to iron results in the suppression of carbonaceous impurity formation without decreasing the SWCNT yield. The purity-enhanced SWCNT shows fairly low sheet resistance due to the improvement of inter-nanotube contacts. This scalable design of SWCNT synthesis with enhanced purity is therefore a promising tool for shaping future high performance devices.
我们报告了一种从铁铜双金属催化剂中高效高纯度合成窄径单壁碳纳米管（SWCNTs）的方法。使用沸石负载醇化学气相沉积法合成了直径为 0.8-1.2nm 的 SWCNTs。我们系统地研究了单金属和双金属催化剂，以实现 SWCNT 产率的提高和不希望的石墨杂质形成的抑制。使用基于超速离心的纯化技术的光学吸收光谱法定量了 SWCNTs 的相对产率和纯度。对于单金属催化剂，与其他金属如钴、镍、钼、铜和铂相比，铁表现出最高的催化活性。研究发现，向铁中添加铜可以抑制碳质杂质的形成，而不会降低 SWCNT 的产率。由于提高了纳米管之间的接触，纯净度提高的 SWCNT 表现出相当低的片电阻。因此，这种具有增强纯度的 SWCNT 合成的可扩展设计是制造未来高性能器件的有前途的工具。
