Dendrimer-templated Fe nanoparticles for the growth of single-wall carbon nanotubes by plasma-enhanced CVD.
Dendrimer-templated Fe nanoparticles for the growth of single-wall carbon nanotubes by plasma-enhanced CVD.
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用于通过等离子体增强 CVD 生长单壁碳纳米管的树枝状模板 Fe 纳米颗粒。
DOI：
10.1021/jp057302d
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
T. Sands
中科院分区：
文献类型：
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作者：
P. Amama;M. Maschmann;T. Fisher;T. Sands
第四代（G4）聚氨基胺（PAMAM）树状大分子（G4- nh2）被用作模板，在SiO2/Si、Ti/Si、蓝宝石和多孔阳极氧化铝（PAA）衬底上传递几乎单分散的纳米催化剂。固定化Fe3+/G4-NH2复合材料煅烧后得到的Fe2O3纳米颗粒作为微波等离子体增强CVD （PECVD）生长单壁碳纳米管（SWNTs）的“种子”。为了克服通过PECVD生长SWNT的困难，已经确定了促进Fe纳米颗粒稳定性的反应条件，从而提高了SWNT的选择性和质量。特别是，在N2气氛中原位退火Fe催化剂可以提高SWNT的选择性和质量。在900摄氏度下进行5分钟的H2预还原也可以提高SiO2/Si负载催化剂的SWNT选择性和质量，尽管蓝宝石负载催化剂的质量较低。在SWNT生长过程中施加正直流偏置电压（+200 V）可以非常有效地去除非晶碳杂质，同时增强石墨化，SWNT选择性和垂直排列。本研究的结果将促进不同衬底上的Fe纳米颗粒的使用，以促进PECVD生长高质量的swcnts。
A fourth-generation (G4) poly(amidoamine) (PAMAM) dendrimer (G4-NH2) has been used as a template to deliver nearly monodispersed catalyst nanoparticles to SiO2/Si, Ti/Si, sapphire, and porous anodic alumina (PAA) substrates. Fe2O3 nanoparticles obtained after calcination of the immobilized Fe3+/G4-NH2 composite served as catalytic "seeds" for the growth of single-wall carbon nanotubes (SWNTs) by microwave plasma-enhanced CVD (PECVD). To surmount the difficulty associated with SWNT growth via PECVD, reaction conditions that promote the stabilization of Fe nanoparticles, resulting in enhanced SWNT selectivity and quality, have been identified. In particular, in situ annealing of Fe catalyst in an N2 atmosphere was found to improve SWNT selectivity and quality. H2 prereduction at 900 degrees C for 5 min was also found to enhance SWNT selectivity and quality for SiO2/Si supported catalyst, albeit of lower quality for sapphire supported catalyst. The application of positive dc bias voltage (+200 V) during SWNT growth was shown to be very effective in removing amorphous carbon impurities while enhancing graphitization, SWNT selectivity, and vertical alignment. The results of this study should promote the use of exposed Fe nanoparticles supported on different substrates for the growth of high-quality SWNTs by PECVD.