Synthesis of carbon nanotubes on Ni/carbon-fiber catalysts under mild conditions
Synthesis of carbon nanotubes on Ni/carbon-fiber catalysts under mild conditions
复制标题
DOI：
10.1016/j.carbon.2003.12.076
复制
发表时间：
2004-01-01
期刊：
影响因子：
10.9
通讯作者：
Tanabe, E
中科院分区：
文献类型：
--
作者：
Otsuka, K;Abe, Y;Tanabe, E
甲烷、正己烷、苯和环戊二烯在气相生长碳纤维(VGCF)或石墨化碳纤维(GCF)负载的镍催化剂上的分解温度相对较低(773K)。透射电子显微镜显示，纤维的形态随碳氢化合物和颗粒大小的不同而变化。甲烷和正己烷的分解生成鱼骨型纤维。正己烷纤维有时会出现间歇性的中空结构，但纤维的直径分布广泛。苯和环戊二烯的分解主要生成直径相对均匀的缠绕型碳纳米管(10-20 nm)。双向鱼骨型纤维(从中心催化剂颗粒向外生长的纤维)也作为副产品被观察到。管状纤维顶端有细小的镍颗粒(10-20 nm)，尾巴呈伸展状，其中一些颗粒经常改变生长方向。这种不同的管状形态可以归因于液状镍颗粒，这是由于在苯或环戊二烯分解过程中碳的快速溶解导致凝固点下降所致。在正己烷的分解过程中也观察到双向纤维的形成。较大的镍颗粒(直径50-110 nm)生长出双向纤维。(C)2004爱思唯尔有限公司。保留所有权利。
Methane, n-hexane, benzene, and cyclopentadiene were decomposed at a relatively mild temperature (773 K) over a Ni catalyst supported on either vapor grown carbon fibers (VGCF) or graphitized carbon fibers (GCF). Transmission electron microscopy showed that the morphology of the fibers changed according to hydrocarbon and particle size. Decomposition of methane and n-hexane produced fishbone-type fibers. The fibers from n-hexane sometimes showed intermittent hollow structures but the diameters of the fibers were widely distributed. Decomposition of benzene and cyclopentadiene mainly produced winding type carbon nanotubes of relatively uniform diameters (10-20 nm). Bidirectional fishbone-type fibers (fibers growing outward from a central catalyst particle) were also observed as a by-product. Small Ni particles (10-20 nm) with stretched tails were present on the tips of tubular fibers, some of which frequently changed growth direction. The varying tubular morphologies can be ascribed to liquid-like Ni particles resulting from the freezing point depression due to a fast dissolution of carbons during decomposition of benzene or cyclopentadiene. The formation of bidirectional fibers was also observed in the decomposition of n-hexane. Relatively large well-faceted Ni particles (diameter 50-110 nm) grew bidirectional fibers. (C) 2004 Elsevier Ltd. All rights reserved.