Coverage-dependent adsorption and desorption of oxygen on Pd(100)
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, P.O. Box 9502, 2300 RA Leiden (Netherlands)
- Department of Chemistry, California State University Fresno, 2555 E. San Ramon Ave., Fresno, California 93740 (United States)
We have studied the adsorption and desorption of O{sub 2} on Pd(100) by supersonic molecular beam techniques and thermal desorption spectroscopy. Adsorption measurements on the bare surface confirm that O{sub 2} initially dissociates for all kinetic energies between 56 and 380 meV and surface temperatures between 100 and 600 K via a direct mechanism. At and below 150 K, continued adsorption leads to a combined O/O{sub 2} overlayer. Dissociation of molecularly bound O{sub 2} during a subsequent temperature ramp leads to unexpected high atomic oxygen coverages, which are also obtained at high incident energy and high surface temperature. At intermediate temperatures and energies, these high final coverages are not obtained. Our results show that kinetic energy of the gas phase reactant and reaction energy dissipated during O{sub 2} dissociation on the cold surface both enable activated nucleation of high-coverage surface structures. We suggest that excitation of local substrate phonons may play a crucial role in oxygen dissociation at any coverage.
- OSTI ID:
- 22676018
- Journal Information:
- Journal of Chemical Physics, Vol. 144, Issue 24; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
Vibrational studies of interfaces using high-resolution electron energy loss spectroscopy
Nitric oxide adsorption, decomposition, and desorption on Rh(100)