Novel Method to Evaluate the Carbon Network of Single-Walled Carbon Nanotubes by Hydrogen Physisorption
Novel Method to Evaluate the Carbon Network of Single-Walled Carbon Nanotubes by Hydrogen Physisorption
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DOI：
10.1021/jp076275j
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发表时间：
2007-09
影响因子：
3.7
通讯作者：
S. Iwata;Y. Sato;K. Nakai;S. Ogura;T. Okano;Masaru Namura;A. Kasuya;K. Tohji;K. Fukutani
中科院分区：
文献类型：
--
作者：
S. Iwata;Y. Sato;K. Nakai;S. Ogura;T. Okano;Masaru Namura;A. Kasuya;K. Tohji;K. Fukutani
单壁碳纳米管（SWCNTs）的物理和化学性质对管状石墨烯中的缺陷非常敏感。然而，迄今为止，表征单壁碳纳米管缺陷的方法仅限于透射电子显微镜（TEM）和原子力显微镜（AFM），它们只能用于观察单壁碳纳米管的局部结构。为了探索单壁碳纳米管的评价方法，采用低温热脱附光谱（cryo-TDS）研究了H2在高质量单壁碳纳米管上的物理吸附，发现H2对单壁碳纳米管的缺陷特别敏感。TDS显示纯化的SWCNT在20 K（α）下的尖锐解吸峰，并且对于空气氧化的SWCNT在27和24 K（β和γ）下观察到另外的解吸信号。在单壁碳纳米管束的沟槽位置和间隙通道处以及单壁碳纳米管内部，a、β和y峰分别归因于H2。发现α峰的尖锐度以及α与β和γ的比值强烈地依赖于样品制备条件。利用低温TDS技术，可以可靠且灵敏地评估单壁碳纳米管的碳网络的完善性。
Physical and chemical properties of single-walled carbon nanotubes (SWCNTs) are sensitive to the defects in the tubular graphene. To date, however, the method to characterize the defect of SWCNTs has been limited to transmission electron microscopy (TEM) and atomic force microscopy (AFM), which can only be used to observe the local structure of SWCNTs. In an effort to explore the evaluation method of SWCNTs, physisorption of H 2 on high-quality SWCNTs was investigated by cryogenic thermal-desorption spectroscopy (cryo-TDS), which revealed particular sensitivity to the defects of SWCNTs. TDS showed a sharp desorption peak at 20 K (a) for as-purified SWCNTs, and additional desorption signals were observed at 27 and ∼24 K β and y) for air-oxidized SWCNTs. The a, β, and y peaks were attributed to H 2 at the groove site and interstitial channel of a SWCNT bundle and inside of SWCNT, respectively. The sharpness of the a peak and the ratio of a to β and y were found to depend strongly on the sample preparation condition. With this cryo-TDS technique, the perfectibility of the carbon network of SWCNTs can be reliably and sensitively evaluated.