Elucidation of the enhancement mechanism of carbon nanotube growth by combustion plasma

燃烧合成碳纳米管（CNT）是一种热等离子体与热源和碳源共存的方法，有望实现碳纳米管的低成本批量生产。研究发现，施加直流电场可以促进碳纳米管在该方法中的生长。本研究考察了电场对碳纳米管形成场的温度变化、化学物质浓度、碳纳米管形成量和特性的影响。研究了电场对碳纳米管在电炉中生长的影响。结果表明，在燃烧合成过程中，碳纳米管的生长得到了促进，碳纳米管的结晶得到了改善。本文认为，电场对燃烧合成过程中碳纳米管生成的影响可能是由于热等离子体运动导致碳纳米管的收集增加和催化活性的提高。

Combustion synthesis of carbon nanotube (CNT), in which thermal plasma is coexist with heat and carbon sources, is expected to make the mass production of CNT with low cost possible. It has been found that the CNT growth in this method is promoted by applying the direct current electric field. In this study, the effect of electric field on the change in temperature, concentration of chemical species of the CNT formation field, the amount and characteristics of the CNT formed are investigated. The effect of electric field on the CNT growth in the electric furnace is also investigated. As a result, the promotion of CNT growth and improvement of crystallization of CNT are observed in the combustion synthesis. It is suggested that the effect of electric field on the CNT manufacturing in the combustion synthesis can be ascribed to the increase in collection of CNT formed due to the motion of thermal plasma and the promotion of catalytic activity.