Chemisorption of Carbon Monoxide on Three Metal Surfaces: Ni(111), Pd(111) and Pt(111. A Comparative Study
Abstract
At one-third coverage of carbon monoxide, a (3 x 3)R30 deg low energy electron diffraction (LEED) pattern has been observed on Ni(111), Pd(111) and Pt(111). Interestingly, the C-O stretching frequency indicates three completely different adsorption sites; a 2-fold bridge site for Ni(111), a 3-fold site for Pd(111), and an on-top site for Pt(111). As the coverage increases to one-half, a c(4x2) Leed pattern appears. For Ni(111) and pd (111), the adsorbate seems to prefer the 2-fold site. On Pt(111), half of the chemisorbed CO sits on the on- top site while the other half is located at the 2-fold site. Further increase in coverage results in titled CO molecules on Pt(111) and adsorption of CO at the on-top site of Ni(111) and Pd(111). To rationalize these observations, we carried out extended Huckel calculations within the tight-binding formalism. Our discussion is augmented by conceptual tools such as density of states and crystal orbital overlap population. We also examine the question of the adequacy of the Blyholder model in describing the adsorbate-surface interaction. (js)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 12, 1990
- Accession Number
- ADA228579
Entities
People
- Roald Hoffmann
- Yat-ting Wong
Organizations
- Cornell University Department of Chemistry and Chemical Biology