Division of Chemistry & Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
Phys Chem Chem Phys. 2013 Apr 21;15(15):5615-9. doi: 10.1039/c3cp50348h.
Carbon nanotubes (CNTs) have a tremendous amount of potential to become useful components for future practical applications that may become a part of everyday life. While the sp(2) carbon itself is a rather chemically inert material, the issue of residual metal nanoparticle catalysts remains a prominent barrier in the utilization of CNTs in many areas due to the strong influence of these metallic impurities on the redox chemistry of biomarkers. Even with a standard purification procedure, CNTs have been shown to still contain residual metal nanoparticle catalysts. As such, presented in this paper is an improved purification technique for treating the CNTs with the highly reactive Cl2 gas at an elevated temperature of 1000 °C for 10 min, which would result in the vaporization of the metallic impurities as MxCly, leading to a large decrease in the amount of metallic nanoparticle impurities within the CNTs. By means of electrochemistry and X-ray fluorescence analysis, we demonstrate that the behaviour of such Cl2 treated CNTs showed a significant shift towards that of high purity CNTs, with a dramatic decrease in the influence of the residual metallic impurities on the electrochemical behaviour of CNTs. Therefore it is suggested that the Cl2 treatment of carbon nanotubes is a highly promising route towards the production of pure CNTs.
碳纳米管 (CNTs) 具有巨大的潜力成为未来实际应用的有用组件，可能成为日常生活的一部分。虽然 sp(2) 碳本身是一种化学惰性材料，但由于这些金属杂质对生物标志物的氧化还原化学有强烈影响，残留的金属纳米颗粒催化剂问题仍然是在许多领域中利用 CNTs 的一个突出障碍。即使采用标准的纯化程序，也已经表明 CNTs 仍然含有残留的金属纳米颗粒催化剂。因此，本文提出了一种改进的纯化技术，即用高度反应性的 Cl2 气体在 1000°C 的高温下处理 CNTs 10 分钟，这将导致金属杂质以 MxCly 的形式蒸发，从而大大减少 CNTs 中的金属纳米颗粒杂质的数量。通过电化学和 X 射线荧光分析，我们证明了这种经过 Cl2 处理的 CNTs 的行为明显向高纯 CNTs 偏移，残留金属杂质对 CNTs 电化学行为的影响显著降低。因此，建议对碳纳米管进行 Cl2 处理是生产纯 CNTs 的一种很有前途的途径。
