Thermodynamic stability and structure of copper oxide surfaces

A first-principles investigation

Aloysius Soon, Mira Todorova, Bernard Delley, Catherine Stampfl

Research output: Contribution to journalArticle

197 Citations (Scopus)

Abstract

To obtain insight into the structure and surface stoichiometry of copper-based catalysts in commercially important chemical reactions such as the oxygen-assisted water-gas shift reaction, we perform density-functional theory calculations to investigate the relative stability of low-index copper oxide surfaces. By employing the technique of "ab initio atomistic thermodynamics," we identify low-energy surface structures that are most stable under realistic catalytic conditions are found to exhibit a metallic character. Three surfaces are shown to have notably lower surface free energies compared to the others considered and could be catalytically relevant; in particular, under oxygen-rich conditions, they are the Cu2 O (110): CuO surface, which is terminated with both Cu and O surface atoms, and the Cu2 O (111) - CuCUS surface, which contains a surface (coordinatively unsaturated) Cu vacancy, while for the oxygen-lean conditions, the Cu2 O (111) surface with a surface interstitial Cu atom is found to be energetically most favorable, highlighting the importance of defects at the surface.

Original languageEnglish
Article number125420
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume75
Issue number12
DOIs
Publication statusPublished - 2007 Mar 21

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Copper oxides
copper oxides
Thermodynamic stability
thermodynamics
Oxygen
oxygen
Atoms
Water gas shift
Surface structure
Stoichiometry
Free energy
surface energy
Vacancies
Density functional theory
atoms
Copper
Chemical reactions
stoichiometry
chemical reactions
interstitials

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

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Thermodynamic stability and structure of copper oxide surfaces : A first-principles investigation. / Soon, Aloysius; Todorova, Mira; Delley, Bernard; Stampfl, Catherine.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 75, No. 12, 125420, 21.03.2007.

Research output: Contribution to journalArticle

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AB - To obtain insight into the structure and surface stoichiometry of copper-based catalysts in commercially important chemical reactions such as the oxygen-assisted water-gas shift reaction, we perform density-functional theory calculations to investigate the relative stability of low-index copper oxide surfaces. By employing the technique of "ab initio atomistic thermodynamics," we identify low-energy surface structures that are most stable under realistic catalytic conditions are found to exhibit a metallic character. Three surfaces are shown to have notably lower surface free energies compared to the others considered and could be catalytically relevant; in particular, under oxygen-rich conditions, they are the Cu2 O (110): CuO surface, which is terminated with both Cu and O surface atoms, and the Cu2 O (111) - CuCUS surface, which contains a surface (coordinatively unsaturated) Cu vacancy, while for the oxygen-lean conditions, the Cu2 O (111) surface with a surface interstitial Cu atom is found to be energetically most favorable, highlighting the importance of defects at the surface.

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