Details
| Original language | English |
|---|---|
| Pages (from-to) | 7446-7455 |
| Number of pages | 10 |
| Journal | Journal of Physical Chemistry C |
| Volume | 111 |
| Issue number | 20 |
| Early online date | 27 Apr 2007 |
| Publication status | Published - 1 May 2007 |
Abstract
The adsorption and diffusion of potassium and oxygen on Rh(110), as well as the coadsorption of K and O and its effect on K diffusion, have been studied using periodic density functional theory (DFT) calculations (PW91-GGA). On both the nonreconstructed (1 × 1) and the missing-row (MR) reconstructed surfaces, O prefers the short bridge site at low coverage, with a binding energy of ca. -5.2 eV at 1/4 ML. At θo > 1/2 ML, O atoms occupy alternating threefold sites along the ridge and form a zigzag pattern. Interaction with the ridge sites is enhanced by the MR reconstruction. Potassium prefers to be in the trough, with a binding energy of -2.3 eV on the (1 × 1) surface and -2.9 eV on the MR surface at 1/8 ML. Thus, the adsorption of both O and K at low to medium coverage promotes the MR reconstruction. The coadsorption of K and O enhances the binding energy of K to a maximum of -3.6 eV at the highest oxygen coverage studied, 13/8 ML. Oxygen adsorption is also stabilized by K, though to a smaller extent on a per-O-atom basis. On both surfaces, K prefers to diffuse in the [11̄0] direction with a barrier of ca. 0.05 eV. Oxygen diffusion also prefers the [11̄0] direction on the MR surface but is not clearly anisotropic on the (1 × 1) surface. The barrier to O diffusion ranges from 0.6-0.8 eV depending on the coverage and reconstruction. In the presence of coadsorbed O, the diffusion barrier of K tops out at ca. 0.12 eV, much lower than earlier estimates based on mean-field models. Possible reasons for this apparent contradiction are discussed.
ASJC Scopus subject areas
- Materials Science(all)
- Electronic, Optical and Magnetic Materials
- Energy(all)
- General Energy
- Chemistry(all)
- Physical and Theoretical Chemistry
- Materials Science(all)
- Surfaces, Coatings and Films
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In: Journal of Physical Chemistry C, Vol. 111, No. 20, 01.05.2007, p. 7446-7455.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - The effect of coadsorbed oxygen on the adsorption and diffusion of potassium on Rh(110)
T2 - A first-principles study
AU - Xu, Ye
AU - Marbach, Hubertus
AU - Imbihl, Ronald
AU - Kevrekidis, Ioannis G.
AU - Mavrikakis, Manos
PY - 2007/5/1
Y1 - 2007/5/1
N2 - The adsorption and diffusion of potassium and oxygen on Rh(110), as well as the coadsorption of K and O and its effect on K diffusion, have been studied using periodic density functional theory (DFT) calculations (PW91-GGA). On both the nonreconstructed (1 × 1) and the missing-row (MR) reconstructed surfaces, O prefers the short bridge site at low coverage, with a binding energy of ca. -5.2 eV at 1/4 ML. At θo > 1/2 ML, O atoms occupy alternating threefold sites along the ridge and form a zigzag pattern. Interaction with the ridge sites is enhanced by the MR reconstruction. Potassium prefers to be in the trough, with a binding energy of -2.3 eV on the (1 × 1) surface and -2.9 eV on the MR surface at 1/8 ML. Thus, the adsorption of both O and K at low to medium coverage promotes the MR reconstruction. The coadsorption of K and O enhances the binding energy of K to a maximum of -3.6 eV at the highest oxygen coverage studied, 13/8 ML. Oxygen adsorption is also stabilized by K, though to a smaller extent on a per-O-atom basis. On both surfaces, K prefers to diffuse in the [11̄0] direction with a barrier of ca. 0.05 eV. Oxygen diffusion also prefers the [11̄0] direction on the MR surface but is not clearly anisotropic on the (1 × 1) surface. The barrier to O diffusion ranges from 0.6-0.8 eV depending on the coverage and reconstruction. In the presence of coadsorbed O, the diffusion barrier of K tops out at ca. 0.12 eV, much lower than earlier estimates based on mean-field models. Possible reasons for this apparent contradiction are discussed.
AB - The adsorption and diffusion of potassium and oxygen on Rh(110), as well as the coadsorption of K and O and its effect on K diffusion, have been studied using periodic density functional theory (DFT) calculations (PW91-GGA). On both the nonreconstructed (1 × 1) and the missing-row (MR) reconstructed surfaces, O prefers the short bridge site at low coverage, with a binding energy of ca. -5.2 eV at 1/4 ML. At θo > 1/2 ML, O atoms occupy alternating threefold sites along the ridge and form a zigzag pattern. Interaction with the ridge sites is enhanced by the MR reconstruction. Potassium prefers to be in the trough, with a binding energy of -2.3 eV on the (1 × 1) surface and -2.9 eV on the MR surface at 1/8 ML. Thus, the adsorption of both O and K at low to medium coverage promotes the MR reconstruction. The coadsorption of K and O enhances the binding energy of K to a maximum of -3.6 eV at the highest oxygen coverage studied, 13/8 ML. Oxygen adsorption is also stabilized by K, though to a smaller extent on a per-O-atom basis. On both surfaces, K prefers to diffuse in the [11̄0] direction with a barrier of ca. 0.05 eV. Oxygen diffusion also prefers the [11̄0] direction on the MR surface but is not clearly anisotropic on the (1 × 1) surface. The barrier to O diffusion ranges from 0.6-0.8 eV depending on the coverage and reconstruction. In the presence of coadsorbed O, the diffusion barrier of K tops out at ca. 0.12 eV, much lower than earlier estimates based on mean-field models. Possible reasons for this apparent contradiction are discussed.
UR - http://www.scopus.com/inward/record.url?scp=34250316552&partnerID=8YFLogxK
U2 - 10.1021/jp070654v
DO - 10.1021/jp070654v
M3 - Article
AN - SCOPUS:34250316552
VL - 111
SP - 7446
EP - 7455
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 20
ER -