AVS 52nd International Symposium
    Surface Science Monday Sessions
       Session SS1-MoM

Paper SS1-MoM9
The Mechanism of Partial Oxidation of Styrene on Ag(111)

Monday, October 31, 2005, 11:00 am, Room 202

Session: Catalytic Chemistry of Hydrocarbons
Presenter: A. Klust, Stanford University
Authors: A. Klust, Stanford University
R.J. Madix, Stanford University
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The partial oxidation of olefins on Ag surfaces has been a long standing problem in surface science and is of great commercial interest. In particular, the nature of reaction intermediates has been subject of intense debate. One candidate for the reaction intermediate is the oxametallacycle where both ends of a -C-C-O- chain are attached to the Ag surface (see e.g. [1]). We present a temperature programmed reaction spectroscopy (TPRS) and x-ray photoelectron spectroscopy (XPS) study of the partial oxidation of styrene on Ag(111). The reaction products are CO@sub 2@, H@sub 2@O, styrene oxide, benzene, and benzoic acid. XPS gives evidence for two different intermediate structures that we assign to an oxametallacycle and to benzoate. The oxametallacycle seems to be the precursor for the formation of the styrene oxide as well as for the formation of the benzoate while the benzoate itself leads to the formation of CO@sub 2@, benzene, and benzoic acid. The results are explained in the framework of a model based on the asymmetry of the oxametallacycle caused by the phenyl ring of styrene. @FootnoteText@ @footnote 1@ S. Linic and M. A. Barteau, J. Am. Chem. Soc. 125 (2003) 4034.