Document Type
Article
Publication Date
6-6-2016
Publication Title
ACS Catalysis
Volume
6
Issue
7
Pages
4640-4646
Publisher Name
American Chemical Society
Abstract
A long-standing challenge in the study of heterogeneously catalyzed reactions on silver surfaces has been the determination of what oxygen species are of greatest chemical importance. This is due to the coexistence of several different surface phases on oxidized silver surfaces. A further complication is subsurface oxygen (Osub). Osub are O atoms absorbed into the near surface of a metal, and are expected to alter the surface in terms of chemistry and structure, but these effects have yet to be well characterized. We studied oxidized Ag(111) surfaces after exposure to gas-phase O atoms to determine how Osub is formed and how its presence alters the resultant surface structure. Using a combination of surface science techniques to quantify Osub formation and the resultant surface structure, we observed that once 0.1 ML of Osub has formed, the surface dramatically, and uniformly, reconstructed to a striped phase at the expense of all other surface phases. Furthermore, Osub formation was hindered at temperatures above 500 K. The thermal dependence for Osub formation suggests that at industrial catalytic conditions of 475 – 500 K for the epoxidation of ethylene-to-ethylene oxide, Osub would be present and is a factor in the subsequent reactivity of the catalysts. These findings point to the need for the incorporation of Osub into catalytic models as well as further theoretical investigation of the resultant structure observed in the presence of Osub.
Recommended Citation
Derouin, Jonathan; Farber, Rachael G.; Turano, Marie E.; Iski, Erin V.; and Killelea, Daniel. Thermally Selective Formation of Subsurface Oxygen in Ag(111) and Consequent Surface Structure. ACS Catalysis, 6, 7: 4640-4646, 2016. Retrieved from Loyola eCommons, Chemistry: Faculty Publications and Other Works, http://dx.doi.org/10.1021/acscatal.6b01239
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Copyright Statement
© 2016 American Chemical Society.
Comments
Author Posting. © American Chemical Society, 2016. This is the author's version of the work. It is posted here by permission of the American Chemical Society for personal use, not for redistribution. The definitive version was published in ACS Catalysis, http://dx.doi.org/10.1021/acscatal.6b01239.