AVS 63rd International Symposium & Exhibition
    Fundamental Discoveries in Heterogeneous Catalysis Focus Topic Thursday Sessions
       Session HC+SS-ThA

Paper HC+SS-ThA2
Role of Oxygen at the Surface and Subsurface during Catalytic Oxidation by Silver

Thursday, November 10, 2016, 2:40 pm, Room 103A

Session: Advances in Theoretical Models and Simulations of Heterogeneously-catalyzed Reactions
Presenter: Sharani Roy, University of Tennessee
Correspondent: Click to Email
Catalytic oxidation by the silver surface is used in several important industrial processes, such as epoxidation of ethylene to form polyethylene or partial oxidation of methane to form methanol. To understand the mechanisms of catalytic oxidation at the molecular level, it is essential to understand the interactions of atomic oxygen with the silver surface. We present a detailed theoretical study of oxygen adsorbed on the surface and subsurface of silver based on density functional theory and molecular dynamics simulations. Our ultimate goal is to develop a conceptual model of reactivity of surface oxygen and subsurface oxygen in catalytic oxidation by the silver surface. While the detailed quantum chemical calculations serve to accurately model the ground-state potential energy landscape of the oxygen-silver system, molecular dynamics simulates the motion of oxygen on the surface and subsurface at realistic laboratory or catalytic temperatures. We focus on several important phenomena, including surface-site preference, coverage dependence, and temperature dependence of oxygen adsorption at the surface and subsurface. We also investigate the changes in the surface structure of silver induced by the presence of oxygen. Due to the differences in structure, interatomic spacing, and binding sites of the (111) and (110) faces of the silver crystal, the adsorption properties of atomic oxygen vary for the two surfaces. Our study determines some fundamental differences in silver-oxygen interactions on the two surfaces, and provides qualitative insight on how the choice of surface can affect the participation of surface and subsurface oxygen in catalytic oxidation by silver. Future work will explore the interactions of surface oxygen and subsurface oxygen with reactant molecules such as methane or ethylene.