In situ observations of catalyst dynamics during surface-bound carbon nanotube nucleation
In situ observations of catalyst dynamics during surface-bound carbon nanotube nucleation
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DOI：
10.1021/nl0624824
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发表时间：
2007-03-01
期刊：
影响因子：
10.8
通讯作者：
Robertson, John
中科院分区：
文献类型：
--
作者：
Hofmann, Stephan;Sharma, Renu;Robertson, John
我们展示了单壁碳纳米管和纳米纤维的表面结合催化化学气相沉积的原子尺度，视频速率环境透射电子显微镜和原位时间分辨x射线光电子能谱。我们观察到SiOx载体上的过渡金属催化剂纳米颗粒在纳米管形成之前和过程中表现出晶格条纹对比和高变形性。单壁碳纳米管通过碳帽的升起而成核。碳帽的稳定和纳米管的生长涉及催化剂纳米晶体本身的动态重塑。对于碳纳米纤维，石墨烯层的堆叠是由其尖端催化剂纳米颗粒的连续伸长和收缩决定的。
We present atomic-scale, video-rate environmental transmission electron microscopy and in situ time-resolved X-ray photoelectron spectroscopy of surface-bound catalytic chemical vapor deposition of single-walled carbon nanotubes and nanofibers. We observe that transition metal catalyst nanoparticles on SiOx support show crystalline lattice fringe contrast and high deformability before and during nanotube formation. A single-walled carbon nanotube nucleates by lift-off of a carbon cap. Cap stabilization and nanotube growth involve the dynamic reshaping of the catalyst nanocrystal itself. For a carbon nanofiber, the graphene layer stacking is determined by the successive elongation and contraction of the catalyst nanoparticle at its tip.