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

点击翻译按钮获取中文摘要

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.