Thermal Decomposition of Carbon Precursors in Decorated AFI Zeolite Crystals
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- 作者：Jian Pang Zhai ; Zi Kang Tang ; Frank L. Y. Lam ; Xijun Hu
- 刊名：Journal of Physical Chemistry B
- 出版年：2006
- 出版时间：October 5, 2006
- 年：2006
- 卷：110
- 期：39
- 页码：19285 - 19290
- 全文大小：129K
- 年卷期：v.110,no.39(October 5, 2006)
- ISSN：1520-5207
文摘
Mass spectrometry and thermogravimetric analysis are used to explore the thermal decomposition of carbonprecursors (primarily the tripropylammonium cations) occluded within AlPO4-5 (AFI) crystals prepared invarious media (in the presence or absence of F- ions, Si4+ substations of P5+), with the aim to fabricatehigh-density 0.4-nm single-walled carbon nanotubes (SWNTs). It has been found that the tripropylammoniumprecursors exist in the as-synthesized crystals in three different forms: tripropylammonium fluoride, hydroxide,and tripropylammonium cation compensating for the negative charge of the framework. The latter is bondedto the framework by strong chemical interaction and its decomposition takes place by a series of 
-eliminationreactions to give propylene and ammonia, with the stepwise formation of dipropylammonium andn-propylammonium cations. The 0.4-nm SWNTs filling density was found to be higher than that resultingfrom the carbon precursor of tripropylammonium fluoride and hydroxide, because of the strong adsorptionforce of the channel walls to pyrolysate, as evidenced by the clear and strong radial breathing modes inRaman spectra.
-eliminationreactions to give propylene and ammonia, with the stepwise formation of dipropylammonium andn-propylammonium cations. The 0.4-nm SWNTs filling density was found to be higher than that resultingfrom the carbon precursor of tripropylammonium fluoride and hydroxide, because of the strong adsorptionforce of the channel walls to pyrolysate, as evidenced by the clear and strong radial breathing modes inRaman spectra.