Electrochemical Properties and Applications of Isolated Single Walled Carbon Nanotubes (SWNTs)

纳米科学和纳米技术目前引起了科学家和企业的极大兴趣。这种兴趣的关键是材料和系统在“纳米尺度”上的新行为，通常与我们宏观世界中的系统行为方式完全不同。当我们观察越来越小的物体时，我们经常会发现意想不到的行为，有时会带来有用的结果，但总是会揭示更多关于我们生活的世界的科学。其中一个重要的例子是对单分子导电的研究，它揭示了新的、迷人的物理学，也展示了制造更小、更快的计算机的巨大希望。在这个领域，“单壁碳纳米管”显示出巨大的潜力，自从十多年前被发现以来，它已经成为全球大量研究的主题。单壁碳纳米管是中空的碳圆柱体，圆柱体壁只有一个原子厚，但长度可达一百万个原子长，宽度比人的头发还小5万倍（相当于一支10公里长的铅笔的纵横比！）我们建议研究这些分子的电化学性质，一次研究几个，甚至只有一个。电化学研究的是由化学过程产生的电或由电产生的化学变化，在日常生活中具有相当重要的意义（例如电池、燃料电池、传感器等）。新电极材料的开发和对纳米级电荷转移的理解的提高是电化学技术和应用未来发展的基础。碳纳米管是一种极具潜力的材料，可以用作电极，并在分子尺度上研究电化学过程。我们希望了解有关这些过程的有趣的新信息，并且由于碳纳米管的宽度很小，我们也希望看到新的现象。例如，在小长度尺度（纳米尺度）上的扩散（分子向电极的运动）被认为与在相对较大距离上的扩散遵循不同的行为。这将影响碳纳米管的电化学，但也将对理解这些小尺度下其他环境下的扩散具有重要意义。我们将获得的知识也可能为碳纳米管电极的工业应用指明道路，最有可能在电催化和化学传感等技术重要领域。此外，我们将了解化学溶液对单壁碳纳米管导电的影响，这将对其未来的电气应用具有重要意义。我们还将利用电化学技术在碳纳米管上沉积少量的金属，如金和铂，形成纳米管模板化的“纳米颗粒”。金属纳米颗粒在催化方面具有重要意义，例如铂纳米颗粒可作为燃料电池的催化剂。这种方法可以使我们高度控制形成的纳米颗粒的大小，从而影响它们的催化活性。

Nanoscience and nanotechnology are currently of considerable interest to scientists and businesses alike. The key to this interest is the novel behaviour of materials and systems at the 'nanoscale', often completely different to the way systems behave in our macroscopic world. As we look at smaller and smaller objects we often find unexpected behaviour, sometimes with useful consequences, but always revealing more about the science of the world in which we live. An important example of this is the study of electrical conduction through single molecules, which has revealed new and fascinating physics, as well as demonstrating great promise for building smaller, faster computers. In this area, 'single walled carbon nanotubes', are showing great potential and have been the subject of a huge amount of research globally since their discovery just over ten years ago. Single walled carbon nanotubes are hollow cylinders of carbon, with cylinder walls only one atom thick, but lengths up to a million atoms long, and widths 50 000 times smaller than a human hair (an equivalent aspect ratio to a pencil 10 km long!). We propose to study the electrochemical properties of these molecules, investigating a few, or even only one, at a time.Electrochemistry deals with either the production of electricity from chemical processes or chemical changes produced by electricity and is of considerable importance in everyday life (e.g. batteries, fuel cells, sensors etc). The development of new electrode materials and an improved understanding of charge transfer at the nanoscale underpins future advances in electrochemical technology and applications. Carbon nanotubes are potentially fascinating materials to use as electrodes and at which to study electrochemical processes at the molecular scale. We hope to learn interesting new information about these processes and we also expect to see new phenomena due to the small width of the carbon nanotubes. For example, diffusion (movement of molecules to the electrode) at small length scales (nanoscale) is thought to follow different behaviour to diffusion over comparatively large distances. This will affect the electrochemistry at carbon nanotubes, but will also be of significance to understanding diffusion in other contexts at these small scales. The knowledge we will gain may also point the way to industrial applications of carbon nanotube electrodes, most likely in the technologically important area of electrocatalysis and chemical sensing. Additionally, we will learn about the effect of chemical solutions on electrical conduction through single walled carbon nanotubes, which will be of significance for their future electrical applications. We will also use electrochemistry to deposit small amounts of metals such as gold and platinum on the carbon nanotubes, forming 'nanoparticles' which have been templated by the nanotubes. Metal nanoparticles are of great importance for catalysis, for example, platinum nanoparticles can be used as catalysts in fuel cells. This approach should give us a high degree of control over the size of the nanoparticles formed, which in turn affects their catalytic activity.