Characterization of Oxygenaceous Species Formed by Exposure of Ag(111) to Atomic Oxygen
The uptake and chemical speciation of oxygen in and on Ag(111) surface is described herein. An Ag(111) surface was exposed to gas-phase oxygen atoms under ultrahigh vacuum compatible conditions at various surface temperatures. The O uptake was quantified using temperature-programmed desorption measurements and showed that oxygen exposures at temperatures above 500 K yielded only surface-adsorbed oxygen in a single surface reconstruction. At temperatures below 500 K, O uptake continued past O surface saturation, and a maximum in the uptake with respect to exposure temperature was observed at 450 K. A model where O atoms must diffuse out of subsurface absorption sites to free room for further O describes this observation. The chemical speciation of the oxygenaceous species formed under these conditions was achieved using X-ray photoelectron spectroscopy. These data show that a single O species initially formed on the surface, but at higher coverages, a new, three-dimensional oxygenaceous phase developed. Because of the importance of silver in heterogeneously catalyzed partial oxidation reactions, these results show that oxygen species embedded below the surface plane must be incorporated into accurate models of Ag-surface catalyzed reactions.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- Arthur J. Schmitt Foundation; Donors of the American Chemical Society Petroleum Research Fund; Loyola UniversityjChicago; National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1604983
- Journal Information:
- Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 2 Vol. 124; ISSN 1932-7447
- Publisher:
- American Chemical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Oxygen Coverage Dependence of NO Oxidation on Pt(111)
Chlorine promoters in selective ethylene epoxidation over Ag(111): a comparison with Ag(110)