Interactions of Oxygen and Hydrogen on Pd(111) surface
The coadsorption and interactions of oxygen and hydrogen on Pd(1 1 1) was studied by scanning tunneling microscopy and density functional theory calculations. In the absence of hydrogen oxygen forms a (2 x 2) ordered structure. Coadsorption of hydrogen leads to a structural transformation from (2 x 2) to a ({radical}3 x {radical}3)R30 degree structure. In addition to this transformation, hydrogen enhances the mobility of oxygen. To explain these observations, the interaction of oxygen and hydrogen on Pd(1 1 1) was studied within the density functional theory. In agreement with the experiment the calculations find a total energy minimum for the oxygen (2 x 2) structure. The interaction between H and O atoms was found to be repulsive and short ranged, leading to a compression of the O islands from (2 x 2) to ({radical}3 x {radical}3)R30 degree ordered structure at high H coverage. The computed energy barriers for the oxygen diffusion were found to be reduced due to the coadsorption of hydrogen, in agreement with the experimentally observed enhancement of oxygen mobility. The calculations also support the finding that at low temperatures the water formation reaction does not occur on Pd(1 1 1).
- Research Organization:
- Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
- Sponsoring Organization:
- Computational Research Division; Materials Sciences Division
- DOE Contract Number:
- AC02-05CH11231
- OSTI ID:
- 938418
- Report Number(s):
- LBNL-929E
- Journal Information:
- Surface Science, Journal Name: Surface Science; ISSN SUSCAS; ISSN 0039-6028
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mechanism of CO oxidation reaction on O-covered Pd(111) surfaces studied with fast x-ray photoelectron spectroscopy: Change of reaction path accompanying phase transition of O domains
Theory of subsurface occupation, ordered structures, and order-disorder transitions for hydrogen on Pd(111)
Ordering of ethylidyne on clean and adsorbate covered Pd(111): Influence of the coadsorption of oxygen
Journal Article
·
Wed Jun 14 00:00:00 EDT 2006
· Journal of Chemical Physics
·
OSTI ID:20783307
Theory of subsurface occupation, ordered structures, and order-disorder transitions for hydrogen on Pd(111)
Journal Article
·
Sat Feb 14 23:00:00 EST 1987
· Phys. Rev. B: Condens. Matter; (United States)
·
OSTI ID:6974954
Ordering of ethylidyne on clean and adsorbate covered Pd(111): Influence of the coadsorption of oxygen
Journal Article
·
Wed Jul 01 00:00:00 EDT 1992
· Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (United States)
·
OSTI ID:7039055