Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5424575 | Surface Science | 2009 | 9 Pages |
Abstract
Competition between the CC functional group with the OH group in allyl alcohol and with the CO group in allyl aldehyde in the adsorption and thermal chemistry on Si(1Â 0Â 0)2Ã1 has been studied by X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD), as well as density-functional theory (DFT) calculations. The similarities found in the C 1s and O 1s spectra for both molecules indicate that the O-H dissociation product for allyl alcohol and [2Â +Â 2] CO cycloaddition product for allyl aldehyde are preferred over the corresponding [2Â +Â 2] CC cycloaddition products. Temperature-dependent XPS and TPD studies further show that thermal evolution of these molecules gives rise to the formation of ethylene, acetylene, and propene on Si(1Â 0Â 0)2Ã1, with additional CO evolution only from allyl alcohol. The formation of these desorption products also supports that the [2Â +Â 2] CC cycloaddition reaction does not occur. In addition, the formation of SiC at 1090Â K is observed for both allyl alcohol and allyl aldehyde. We propose plausible surface-mediated reaction pathways for the formation of these thermal evolution products. The present work illustrates the crucial role of the Si(1Â 0Â 0)2Ã1 surface in selective reactions of the Si dimers with the OâH group in allyl alcohol and with the CO group in allyl aldehyde over the CC functional group common to both molecules.
Related Topics
Physical Sciences and Engineering
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Authors
Maryam Ebrahimi, K.T. Leung,