Regensburg 2004 – wissenschaftliches Programm
O 20.1: Vortrag
Dienstag, 9. März 2004, 11:15–11:30, H45
Adsorption and Oxidation of NH3 on RuO2(110) — •Yuemin Wang, Ursula A. Paulus, Karl Jacobi, and Gerhard Ertl — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin
The epitaxially grown RuO2(110) surface was found to exhibit high catalytic activity for CO oxidation [1, 2]. In the present work the interaction of NH3 with the stoichiometric and O-enriched RuO2(110) surfaces, which the latter exposes a weakly bound atomic oxygen species on-top of the unsaturated Ru atom (Ru-cus), is studied using high-resolution electron energy-loss spectroscopy (HREELS) and thermal desorption spectroscopy (TDS). At the stoichiometric RuO2(110) surface we observed only the molecular adsorption of NH3 on Ru-cus at 85 K, whereas on the O-enriched surface NH3 oxidation occurs with annealing to higher temperature. The reaction products depend on the coverage of O-cus. At low O2 exposures (below 0.3 L) NH3 reacts with O-cus to give rise to N2 and H2O. With increasing oxygen exposure NO is produced and becomes the main product at saturation of O-cus. The formation of other N-containing species such as N2O and NO2 were not observed. Reaction mechanisms for NH3 oxidation will be discussed in detail.  C. Y. Fan, J. Wang, K. Jacobi, G. Ertl, J. Phys. Chem. B 106, 10058(2002).  J. Wang, C. Y. Fan, K. Jacobi, G. Ertl, Surf. Sci. 481, 113 (2001).