摘要
纳米碳管的低温合成是纳米碳管合成的一个重要研究方向 .在众多的合成方法中 ,化学气相沉积法 ,特别是等离子体化学气相沉积法在纳米碳管的低温合成方面意义重大 .本研究利用溶胶 -凝胶法结合等离子体还原 ,获得了负载在SiO2 上的纳米金属钴颗粒 .以甲烷为碳源、氢气为载气 ,在纳米金属钴颗粒的催化作用下 ,利用微波等离子体化学气相沉积法在低于 5 0
Carbon nanotubes are novel materials with unique electrical and mechanical properties. Most of the natures of carbon nanotubes depend on their diameters and chiralities. However, it is very difficult to control the diameter and chirality of carbon nanotubes at high temperatures, and thus limits prospects of the nanotubes. For instance, one of the most promising applications of carbon nanotubes in the future is flat panel display, but the carbon nanotubes synthesized at high temperatures is not useable for this purpose because the strain point of glass is very low. For these reasons, synthesis of carbon nanotubes at low temperatures has become a challenge and received much attention. Among all the procedures for synthesizing nanotubes, chemical vapor deposition, especially plasma chemical vapor deposition (PCVD), has great potential in synthesizing carbon nanotubes at low temperatures. In this paper, cobalt nanoparticles supported by SiO2 was prepared by sol-gel process and plasma reducing process. Using methane as carbon resource, hydrogen as carrier, carbon nanotubes were synthesized by microwave plasma chemical vapor deposition ( MWPCVD) at temperatures above 460 degreesC but below 500 degreesC under the catalytic effect of cobalt supported by SiO2. During the process of nanotubes growth, the total pressure in the chamber was kept at 2 kPa. The microwave plasma input power was 600 W, with the flow rates of H-2 and CH4 being 80 and 5 similar to 20 seem, respectively. Though some other carbonaceous particles were also deposited and attached on the carbon nanotubes when the flow rate of CH4 was 20 seem, the amount of carbonaceous particles decreased with the decrease of the flow rate of CH4. These results demonstrate that MWPCVD is a very efficient process for the synthesis of carbon nanotubes at low temperatures.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2002年第5期957-960,共4页
Acta Chimica Sinica
