skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The effect of co-adsorbed oxygen on the adsorption and diffusion of potassium on Rh(110): A first-principles study

Abstract

The adsorption and diffusion of potassium and oxygen on Rh(110), as well as the co-adsorption of K and O and its effect on K diffusion, has been studied using periodic density functional theory (DFT) calculations (PW91-GGA). On both the non-reconstructed (1x1) 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 theta_O>1/2 ML O atoms occupy alternating threefold sites along the ridge and forms a zigzag pattern. Interaction with the ridge sites is enhanced by the MR reconstruction. K prefers to be in the trough, with a binding energy of -2.3 eV on the (1x1) 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 co-adsorption of K and O enhances the binding energy of K to a maximum of -3.6 eV at the highest oxygen coverage studied, 1-3/8 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 [110] direction with a barrier of ca. 0.05more » eV. O diffusion also prefers the [110] direction on the MR surface but is not clearly anisotropic on the (1x1) surface. The barrier to O diffusion ranges from 0.6~0.8 eV depending on the coverage and reconstruction. In the presence of co-adsorbed 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.« less

Authors:
 [1];  [2];  [2];  [3];  [4]
  1. ORNL
  2. Universitat Hannover, Germany
  3. Princeton University
  4. University of Wisconsin, Madison
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Center for Nanophase Materials Sciences
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
942233
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry C; Journal Volume: 111; Journal Issue: 20
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ADSORPTION; DIFFUSION; POTASSIUM; RHODIUM; SORPTIVE PROPERTIES; OXYGEN; DENSITY FUNCTIONAL METHOD; BINDING ENERGY

Citation Formats

Xu, Ye, Marbach, Hubertus, Imbihl, Ronald, Kevrekidis, Yannis G, and Mavrikakis, Manos. The effect of co-adsorbed oxygen on the adsorption and diffusion of potassium on Rh(110): A first-principles study. United States: N. p., 2007. Web. doi:10.1021/jp070654v.
Xu, Ye, Marbach, Hubertus, Imbihl, Ronald, Kevrekidis, Yannis G, & Mavrikakis, Manos. The effect of co-adsorbed oxygen on the adsorption and diffusion of potassium on Rh(110): A first-principles study. United States. doi:10.1021/jp070654v.
Xu, Ye, Marbach, Hubertus, Imbihl, Ronald, Kevrekidis, Yannis G, and Mavrikakis, Manos. Mon . "The effect of co-adsorbed oxygen on the adsorption and diffusion of potassium on Rh(110): A first-principles study". United States. doi:10.1021/jp070654v.
@article{osti_942233,
title = {The effect of co-adsorbed oxygen on the adsorption and diffusion of potassium on Rh(110): A first-principles study},
author = {Xu, Ye and Marbach, Hubertus and Imbihl, Ronald and Kevrekidis, Yannis G and Mavrikakis, Manos},
abstractNote = {The adsorption and diffusion of potassium and oxygen on Rh(110), as well as the co-adsorption of K and O and its effect on K diffusion, has been studied using periodic density functional theory (DFT) calculations (PW91-GGA). On both the non-reconstructed (1x1) 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 theta_O>1/2 ML O atoms occupy alternating threefold sites along the ridge and forms a zigzag pattern. Interaction with the ridge sites is enhanced by the MR reconstruction. K prefers to be in the trough, with a binding energy of -2.3 eV on the (1x1) 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 co-adsorption of K and O enhances the binding energy of K to a maximum of -3.6 eV at the highest oxygen coverage studied, 1-3/8 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 [110] direction with a barrier of ca. 0.05 eV. O diffusion also prefers the [110] direction on the MR surface but is not clearly anisotropic on the (1x1) surface. The barrier to O diffusion ranges from 0.6~0.8 eV depending on the coverage and reconstruction. In the presence of co-adsorbed 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.},
doi = {10.1021/jp070654v},
journal = {Journal of Physical Chemistry C},
number = 20,
volume = 111,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • In order to understand the dynamics of oxidation of Nb, we examine the adsorption, absorption, and diffusion of an oxygen atom on, in, and into Nb(110) and Nb(100) surfaces, respectively, using density functional theory. Our calculations predict that the oxygen atom adsorbs on the threefold site on Nb(110) and the fourfold hollow site on Nb(100), and the adsorption energy is -5.08 and -5.18 eV respectively. We find the long and short bridge sites to be transition states for O diffusion on Nb(110), while the on top site is a rank-2 saddle point. In the subsurface region, the oxygen atom prefersmore » the octahedral site, as in bulk niobium. Our results also show that the O atom is more stable on Nb(110) subsurface than on Nb(100) subsurface. The diffusion of oxygen atoms into niobium surfaces passes through transition states where the oxygen atom is coordinated to four niobium atoms. The diffusion barriers of the oxygen atom into Nb(110) and Nb(100) are 1.81 and 2.05 eV, respectively. Analysis of the electronic density of states reveals the emergence of well localized electronic states below the lowest states of clean Nb surfaces due to d-p orbital hybridization.« less
  • The adsorption of CO on TiO{sub 2}(110) is investigated using the full-potential linearized-augmented-plane-wave method. The equilibrium structures of the clean and adsorbed TiO{sub 2}(110) surfaces are optimized through total-energy and atomic force calculations. Two geometries of CO absorption, namely, OC-Ti and CO-Ti, were considered. It is found that the former orientation is preferred. The calculated adsorption energy and redshift of the CO stretch frequency based on the local-density approximation are 0.79 eV/molecule and 23 cm-1, respectively. The gradient corrections reduce the CO-TiO{sub 2} binding energy to 0.25 eV/molecule. CO interacts with the TiO{sub 2}(110) substrate mainly via its 5{sigma} state.more » Significant charge redistribution is involved in the CO/TiO{sub 2}(110) interaction, which changes the Coulomb potential and subsequently causes large shifts in the core and valence states of the CO adsorbate.« less
  • The adsorption of antimony atom on the Ag(110) surface has been studied within the density functional theory framework. It was turned out that Sb-Ag surface alloy was formed in which Sb atoms substitute Ag atom in the outermost layer and subsurface site absorption was not preferred, suggesting that Sb is well segregated to the surface. Geometric analysis showed that rumpling between substitutional Sb and Ag in the alloy surface is negligible. These results are found to agree well with the experimental finding of Nascimento et al. [Surf. Sci. 572 (2004) 337]. In addition, investigation of the diffusion of Ag atommore » on bare and Sb-covered Ag(110) surface showed that Ag adatoms will jump along the so call in-channel direction and Sb substitution has little effect on the diffusion of Ag adatoms on Ag(110) surface. Such diffusion behavior was found to be different from that of Ag adatoms on Ag(111) surface, where the diffusion energy barrier was reported to be significantly increased upon Sb substitution [Phys. Rev. Lett. 73 (1993) 2437].« less
  • We have investigated the structural and electronic properties of water molecule adsorbed silicon dioxide (α-SiO{sub 2}) [110] surface and analyzed the influence of water molecule on its energetics, structure and electronic properties using density functional theory based first principles calculations. The inhomogeneous topology of the α-SiO{sub 2} clean surface promotes a total charge density displacement on the adsorbed water molecule and giving rise to electron-rich as well as hole-rich region. The electronic charge transfer from a α-SiO{sub 2} to the water molecule occurs upon the formation of a partially occupied level laying above conduction band level.
  • Cited by 7