AVS 65th International Symposium & Exhibition
    Fundamental Discoveries in Heterogeneous Catalysis Focus Topic Tuesday Sessions
       Session HC+SS-TuA

Paper HC+SS-TuA7
Formation and Stability of Subsurface Oxygen on Ag(111)

Tuesday, October 23, 2018, 4:20 pm, Room 201A

Session: A Tale of Two Scales: Catalytic Processes and Surface Science
Presenter: Marie Turano, Loyola University Chicago
Authors: M.E. Turano, Loyola University Chicago
S. Isbill, University of Tennessee Knoxville
S. Roy, University of Tennessee Knoxville
R.G. Farber, Loyola University Chicago
E.V. Iski, University of Tulsa
D.R. Killelea, Loyola University Chicago
Correspondent: Click to Email
A long-standing challenge in the study of heterogeneously catalyzed oxidation reactions on silver surfaces is the determination of what surface species are of greatest chemical importance. This is due to the coexistence of several different types of oxygen on oxidized silver surfaces. A further wrinkle is subsurface oxygen (Osub). Osub are O atoms dissolved into the near surface of a metal, and are expected to alter the surface chemistry and structure, however, these effects have yet to be well characterized. To better understand the interactions of oxidized silver surfaces, synergy between experimental and theoretical studies is necessary. We have studied oxidized Ag(111) surfaces after exposure to gas-phase O atoms using a combination of surface science techniques to determine the resultant surface structure. We observed that once 0.1 ML of Osub has formed, the surface dramatically, and uniformly, reconstructs to a striped structure at the expense of all other surface structures. Furthermore, Osub formation is hindered at temperatures above 500 K. We also observed a coexistence of several surface oxides at intermediate deposition temperatures (475-525K), and the predominance of the p(4x5√3) surface reconstruction at elevated temperatures. Recent DFT-calculated desorption energies of O atoms from Ag(111) agree well with experimentally-derived desorption energies, and provide qualitative insight into the formation and stability of Osub at different oxygen coverages.