The deuterium—oxygen reaction on Pt(111): Influence of atomic steps

✍ Scribed by Laurens K. Verheij; Markus B. Hugenschmidt; Ludwig Cölln; Bene Poelsema; George Comsa

• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 681 KB
• Volume: 166
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(90)87145-h

✦ Synopsis

We have investigated the deutetium-oxygen reaction on a Pt( 111) surface, and the influence of atomic steps on this reaction at surface temperatures around 500 K and oxygen coverages @,z-0.0 1. The kinetics of the reaction has been studied with molecular beam relaxation spectroscopy (MBRS), while the surface has been characterized with respect to oxygen coverage and step density by thermal energy atom scattering (TEAS). It appears that the reaction becomes slower in the presence of steps. This is explained by hydroxyl (OD) or deuterium becoming non-reactive when bound at step sites. A model, assuming a fast equilibrium between deurerium bound at step and terrace sites, describes the measurements remarkably well. From the measurements, we derive a value of 4.8 kcal/mol for the difference in binding energy of deuterium at step and terrace sites, in good agreement with previously reported values.