Adsorption and Oxidation of Phenylacetylene and Phenylmethylacetylene on Oxygen-Precovered Cu(111): Effects of Terminal Hydrogen and Atomic Oxygen Coverage

作者：Sohn Youngku^*; Wei Wei; White John M

来源：Journal of Physical Chemistry C, 2008, 112(47): 18531-18536.

DOI：10.1021/jp806067k

Adsorption and oxidation of phenylacetylene (PA) and phenylmethylacetylene (PMA) on atomic oxygen (O((a)))-precovered Cu(111) have been studied by temperature-programmed desorption (TPD) spectroscopy, X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). Oxidation products commonly include H(2)O, CO, and CO(2), and their yields strongly depend on the O((a)) coverage. The desorption profile of parent PA with O((a)) coverage is markedly different from that of parent PMA, which is mainly due to that the terminal C-H bond of the acetylene group of PA is more vulnerable to be attacked by the O((a)) than the hydrogen of the methyl group of PMA. The reactivity of O((a)) is dependent on the O((a)) coverage: it decreases with the increase of the coverage. With the increase of O((a)) coverage, the H(2)O desorption temperature shifts to a higher temperature. The more active O((a)) at low coverage is mainly used for forming H(2)O by cleaving the C-H (or -CH(3)) hydrogen; the less active O((a)) at high coverage is mainly consumed for CO(2), The study of these model molecules would be valuable for further understanding of hydrogenation/dehydrogenation and oxidation reactions of unsaturated organic molecules on O((a))-precovered metal surfaces.

• 出版日期2008-11-27