Abstract
We employ spin-polarized periodic density functional theory (DFT) to characterize CO adsorption and dissociation on the Fe(1 1 0) surface. We investigate the site preference for CO on Fe(1 1 0) at θCO = 0.25 and 0.5 monolayer (ML), for different functional forms of the generalized gradient approximation (GGA) to electron exchange and correlation within DFT. At 0.25 ML, we predict the existence of a new ordered structure comparable in stability to one proposed previously. At 0.5 ML, we confirm the preference of a distorted on-top adsorption configuration suggested by experiment. The calculated heats of adsorption, CO stretching frequencies, and work function changes agree well with experiment. When dissociating from the on-top site, we predict that CO first moves off the on-top site and then goes through a lying-down transition state with a barrier of 1.52 eV. Diffusion of CO on Fe(1 1 0) from the on-top site to the long-bridge site is predicted to have a very small barrier of ∼0.1 eV. Dissociation of CO from the long-bridge site goes through the same transition state as from the on-top site, but the former has a slightly lower barrier. After dissociation, O atoms remain on the surface while C atoms are embedded into Fe(1 1 0), indicating C atoms may readily diffuse into Fe(1 1 0).
Original language | English (US) |
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Pages (from-to) | 167-177 |
Number of pages | 11 |
Journal | Surface Science |
Volume | 570 |
Issue number | 3 |
DOIs | |
State | Published - Oct 20 2004 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry
Keywords
- Carbon monoxide
- Chemisorption
- Density functional calculations
- Iron