Systematic study on the influence of chemical reactions towards understanding root growth of single wall carbon nanotubes

碳纳米管（CNT）的一个关键，也许是最紧迫的问题是清楚地了解其生长机制，因为这目前限制了扩大应用。化学气相沉积（CVD）中可用的催化剂超过了激光蒸发中可用的催化剂，其中只有四种过渡金属（Ni，Co，Pt和Rh）已被证明可以单独催化SWCNT [1]。最近，我们表明，上述四种金属之外的金属可以用于合成单壁CNT（SWCNT），当在激光蒸发中存在O2时[2]此外，激光烧蚀合成在环境温度下成功进行，无需额外加热。然而，关于添加催化剂（例如O2）的使用及其作用的重要问题仍然存在。在本项目中，我们将对激光烧蚀、CVD、激光诱导热解和水电弧放电中单壁碳纳米管的生长进行系统的研究。详细分析了反应参数，如催化剂前体和产物，添加催化剂，底物和温度。这些研究将使用纯条件下的合成反应器，还将包括与X射线光电子能谱仪和质谱仪耦合的CVD反应器的组装，从而允许原位研究。这将使催化剂和前体产物的氧化态的关键信息，以获得这将使我们的理解单壁碳纳米管的形成显着提高。将利用大量的工具，如拉曼和光学吸收光谱，以及显微镜工具，包括透射和扫描电子显微镜，对样品进行表征。这些工具和其他工具将提供有关其电子、光学和磁性的全部信息。表征数据的评估和合成参数的评估将为单壁碳纳米管的实际低温合成提供方向。更重要的是，该项目将使关键的生长机制，如催化剂/添加催化剂/基板耦合过程，被确定，并提供宝贵的知识，将关闭，如果不是桥梁的差距差距，目前阻止控制合成的单壁碳纳米管的选定直径和手性，决定了所有的物理性能。

A key and perhaps the most pressing issue with carbon nanotubes (CNT) is a clear understanding of their growth mechanisms as this currently limits scaling up applications. The available catalysts in chemical vapour deposition (CVD) exceed those available in laser evaporation, where only four transition metals (Ni, Co, Pt and Rh) have been shown to catalyze SWCNT [1] on their own. Recently, we showed that metals outside the above mentioned four could be used to synthesize single wall CNT (SWCNT) when in the presence of O2 in laser evaporation [2] Moreover, laser ablation synthesis was successfully conducted at ambient temperature without additional heating. However, important questions on the use of add catalysts, such as O2 and their role remain. Within the context of this project we will conduct systematic studies on the growth of SWCNT in laser ablation, CVD, laser induced pyrolysis and water arc-discharge. A detailed analysis of the reaction parameters, such as catalysts precursors and products, add-catalysts, substrates and temperature will be conducted. These studies will use synthesis reactors in pure conditions and will also include the assembly of a CVD reactor coupled to an X-ray photoemission spectrometer and mass spectrometer allowing in situ-studies. This will enable key information on the oxidation states of the catalysts and precursor products to be obtained that will enable our understanding of SWCNT formation to be significantly improved. The samples will be characterized utilizing a vast array of tools such as Raman and optical absorption spectroscopy, and microscopy tools including transmission and scanning electron microscopes. These tools and others will provide full information on their electronic, optical and magnetic properties. Assessment of the characterization data and evaluation of the synthesis parameters will provide direction on practical low temperature synthesis of SWCNT. More importantly the project will enable crucial growth mechanisms, such as catalysts/add-catalyst/substrate coupling processes, to be determined and provide invaluable knowledge that will close, if not bridge the gap, that currently prevents controlled synthesis of SWCNT of a chosen diameter and chirality which determines all the physical properties.