Formation and detection of subsurface oxygen at polycrystalline Pd surfaces

Autor: Epling, William S., Hoflund, Gar B., Minahan, David M.
Zdroj: Catalysis Letters; September 1996, Vol. 39 Issue: 3-4 p179-182, 4p
Abstrakt: An ion-sputtered, oxygen-exposed, polycrystalline palladium surface has been studied using ion scattering spectroscopy (ISS) before and after exposures to H2 and CO. A room-temperature exposure to O2 for 1 min at 1 × 10-7 Torr does not yield chemisorbed oxygen in the outermost layer of atoms according to the ISS data. However, subsequent exposure to H2 or CO induces subsurface oxygen formed during the Oa exposure to migrate to the surface under a chemical driving force and populate the outermost atomic layer where it is detected by ISS. This study demonstrates that a reductive treatment can increase the oxygen content of a surface and provides a useful method for examining subsurface oxygen.
Databáze: Supplemental Index