Synthesis of uniform diameter single-wall carbon nanotubes in Co-MCM-41: effects of the catalyst prereduction and nanotube growth temperatures
Synthesis of uniform diameter single-wall carbon nanotubes in Co-MCM-41: effects of the catalyst prereduction and nanotube growth temperatures
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DOI：
10.1016/j.jcat.2004.04.022
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发表时间：
2004-07-25
影响因子：
7.3
通讯作者：
Pfefferle, L
中科院分区：
文献类型：
--
作者：
Chen, Y;Ciuparu, D;Pfefferle, L
催化剂预处理和CO歧化反应条件对CO - mcm -41催化剂上生长的单壁碳纳米管（SWNT）直径均匀性有较大影响。采用热重分析（TGA）、拉曼光谱（Raman spectroscopy）和透射电镜（TEM）对碳负载和碳纳米管直径均匀性进行了监测。在Co-MCM-41预还原过程中，通过原位XANES监测催化剂在预还原过程中的状态和在SWNT生长过程中形成的钴团簇的大小，并在碳沉积后对催化剂样品进行非原位EXAFS。这些实验允许发展SWNT质量和催化剂状态之间的相关性。Co-MCM-41催化剂中钴簇大小的控制对SWNT直径的控制至关重要。钴团簇的大小随预还原温度和SWNT合成温度的变化而变化。通过控制预还原温度和反应温度，可以在Co-MCM-41中生长出直径分布非常窄的SWNT。(C) 2004爱思唯尔公司版权所有。
Catalyst pretreatment and CO disproportionation reaction conditions were observed to strongly affect the diameter uniformity of single-wall carbon nanotubes (SWNT) grown on Co-MCM-41 catalysts. The prereduction and CO disproportionation reaction temperatures were varied systematically while the carbon loading and the SWNT diameter uniformity were monitored by TGA, Raman spectroscopy, and TEM. The state of the catalyst during prereduction and the size of the cobalt clusters formed during the SWNT growth process were monitored by in situ XANES during the prereduction of the Co-MCM-41, and ex situ EXAFS of catalyst samples was performed after carbon deposition. These experiments allow development of correlations between the SWNT quality and the state of the catalyst. Control of the cobalt cluster size in the Co-MCM-41 catalyst is critical to the SWNT diameter control. The size of the cobalt cluster changes with both the prereduction and the SWNT synthesis temperatures. SWNT with a very narrow diameter distribution can be grown in Co-MCM-41 by controlling both the prereduction and the reaction temperatures. (C) 2004 Elsevier Inc. All rights reserved.