Abstract
The interaction of sulfur dioxide with the nearly perfect (101¯2) surface of the corundum transition-metal oxide has been studied using ultraviolet and x-ray photoemission spectroscopies and low-energy electron diffraction. The reaction of with is found to be extremely vigorous, with adsorbing dissociatively and catalyzing the complete oxidation of the surface to and . This result is significant since exposure to large amounts of does not result in the production of large amounts of at the surface. Dissociative adsorption of continues for exposures up to at least L (1 LTorr sec). The reaction is accompanied by large scale surface disorder and by an increase in the work function of 1.32 eV. In contrast, CO adsorbs molecularly for exposures ≥ L, with an extramolecular relaxation-polarization shift of 3.0 eV. For CO exposures ≤ L, the chemisorption mechanism is tentatively identified as dissociative adsorption at defect sites. Inclusive of this study, the interaction of four oxygen-containing molecules (, CO, O, and ) with (101¯2) surfaces has been studied, and their behavior is compared and trends isolated with a view to understanding the oxidation of .
- Received 13 May 1985
DOI:https://doi.org/10.1103/PhysRevB.32.5384
©1985 American Physical Society