Oxygen-Coverage Effects on Molecular Dissociations at a Pt Metal Surface
2009; American Physical Society; Volume: 102; Issue: 7 Linguagem: Inglês
10.1103/physrevlett.102.076101
ISSN1092-0145
AutoresRachel B. Getman, William F. Schneider, Andrew Smeltz, W. Nicholas Delgass, Fabio H. Ribeiro,
Tópico(s)Semiconductor materials and devices
ResumoThe effects of adsorbate coverage on catalytic surface reactions are not well understood. Here, we contrast the rates of O2 and NO2 dissociations, two competing reactions in NO oxidation catalysis, versus oxygen coverage at a Pt(111) surface. In situ x-ray photoelectron spectroscopy experiments show that the NO2 dissociation rate is less sensitive to O coverage than is O2. Density-functional theory simulations reveal an NO2 reaction pathway that is more adaptable to an increasingly crowded surface than is O2 dissociation. While the rates are comparable at low coverage, NO2 dissociation is many orders of magnitude faster at O coverages typical of NO oxidation catalysis.
Referência(s)