Adsorption and thermal reactions of alkanethiols on Pt(111): Dependence on the length of the alkyl chain

T. H. Lin, T. P. Huang, Y. L. Liu, C. C. Yen, Y. H. Lai, W. H. Hung*

*此作品的通信作者

研究成果: 雜誌貢獻期刊論文同行評審

21 引文 斯高帕斯(Scopus)

摘要

The adsorption and thermal decomposition of alkanethiols (R-SH, where R = CH3, C2H5, and C4H9) on Pt(111) were studied with temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS) with synchrotron radiation. Dissociation of sulfhydry 1 hydrogen (RS-H) of alkanethiol results in the formation of alkanethiolate; the extent of dissociation at an adsorption temperature of 110 K depends on the length of the alkyl chain. At small exposure, all chemisorbed CH3SH, C2H5SH, and C4H 9SH decompose to desorb hydrogen below 370 K and yield carbon and sulfur on the surface. Desorption of products containing carbon is observed only at large exposure. In thermal decomposition, alkanethiolate is proposed to undergo a stepwise dehydrogenation: R′-CH2S →R'′CHS→ R'′ CS, R′ = H, CH3, and C 3H7. Further decomposition of the R'-CS intermediate results in desorption of H2 at 400-500 K and leaves carbon and sulfur on the surface. On the basis of TPD and XPS data, we conclude that the density of adsorption of alkanethiol decreases with increasing length of the alkyl chain. C4H9SH is proposed to adsorb mainly with a configuration in which its alkyl group interacts with the surface; this interaction diminishes the density of adsorption of alkanethiols but facilitates dehydrogenation of the alkyl group.

原文英語
頁(從 - 到)14079-14084
頁數6
期刊Journal of Physical Chemistry B
109
發行號29
DOIs
出版狀態已發佈 - 2005 七月 28

ASJC Scopus subject areas

  • 物理與理論化學
  • 表面、塗料和薄膜
  • 材料化學

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