Regensburg 2004 – wissenschaftliches Programm
O 18.1: Vortrag
Dienstag, 9. März 2004, 11:15–11:30, H38
Composition of the surface oxide on Pd(100) in an O2 and CO environment — •Jutta Rogal, Karsten Reuter, and Matthias Scheffler — Fritz-Haber-Institut der MPG, Berlin,Germany
The oxidation of the Pd(100) surface leads to a (√5× √5)R27∘ surface oxide structure, which was recently identified to be essentially a PdO(101) overlayer on Pd(100). In thermodynamic equilibrium with an O2 gas phase this surface oxide represents the most stable phase over a wide range of environmental conditions, suggesting that the surface oxide may play some role in the catalytic oxidation of CO on the Pd(100) surface.
To get a first insight into this catalytic reaction we investigate the structure and composition of the surface oxide in equilibrium with an arbitrary O2 and CO gas environment using density-functional theory and No-dqconstrainedNo-dq atomistic thermodynamics. Studying the simultaneous adsorption of CO and O we arrive at a (T,p)-phase diagram of the stable structures, and discuss possible kinetic effects due to the ongoing reaction.
 M. Todorova et al., Surf. Sci. 541, 101-112 (2003)
 K. Reuter and M. Scheffler, Phys. Rev. B 68, 045407 (2003)