(91f) Density Functional Theory Studies of the Reactivity of Oxide Phases On Pd(111)

Understanding the reactivity of oxide phases on transition metal surfaces under oxygen-rich conditions is valuable to an array of catalytic processes. Several oxide phases that form on Pd(111), such as PdO(101) and Pd5O4, have recently been identified, and their structures have been determined through low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM). We have performed density functional theory (DFT) calculations on the adsorption and reactivity of these oxide phases to H, H2, H2O, and CO. We will discuss the behavior of the oxide phases in the presence of these adsorbates, as well as compare our results to the those of the pure Pd(111) surface. In general, the two-dimensional surface oxides have very distinct reactive behavior from the three-dimensional oxides that form under higher oxygen coverages. We will also compare our DFT results with recent temperature programmed desorption (TPD) studies.