The adsorption of CO,O2, and H2 on Pt: II. Ultraviolet photoelectron spectroscopy studies |
| |
Authors: | D.M. Collins W.E. Spicer |
| |
Affiliation: | Stanford Electronics Laboratories, Stanford, California 94305, USA |
| |
Abstract: | Ultraviolet photoelectron spectroscopy (UPS) has been used to study the chemisorption of CO, O2, and H2 on platinum. Three single crystal surfaces ((111), 6(111) × (100), and 6(111) × (111)) and two polycrystalline surfaces were studied. These studies yielded three important results. First, the most dominant change in the Pt valence band upon gas adsorption was a decrease in the height of the peak immediately below the Fermi level. This decrease was nearly identical for all three gases studied. Second, CO adsorption resulted in the formation of a resonance state ~8 eV below the Fermi level which was attributed to CO molecular orbitals. In contrast, no dominant resonance states were observed for adsorbed O or H. The lack of an O resonance state on platinum is in contrast to the results observed for O adsorbed on Fe and Ni and suggests important differences between the OPt chemisorption bond and the OFe and ONi chemisorption bonds. Finally, adsorption of CO at steps or defects led to a decrease in work function while its adsorption on terraces led to an increase in work function. For H, adsorption at steps led to an increase in work function while adsorption on terraces led to a decrease in work function. The adsorption of O led to an increase in work function on all of the surfaces studied. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|