Surface oxides of the oxygen-copper system: Precursors to the bulk oxide phase?

Aloysius Soon, Mira Todorova, Bernard Delley, Catherine Stampfl

Research output: Contribution to journalArticle

52 Citations (Scopus)

Abstract

To gain an initial understanding of the copper-based catalysts in commercially important chemical reactions such as the oxygen-assisted water-gas shift reaction, we performed density-functional theory calculations, investigating the interaction of oxygen and copper, focusing on the relative stability of surface oxides and oxide surfaces of the O/Cu system. By employing the technique of "ab initio atomistic thermodynamics", we show that surface oxides are only metastable at relevant pressures and temperatures of technical catalysis, with no stable chemisorption phase observed even at very low coverage. Although exhibiting only metastability, these surface oxides resemble the bulk oxide material both geometrically and electronically, and may serve as a precursor phase before onset of the bulk oxide phase. Having identified the bulk oxide as the most stable phase under realistic catalytic conditions, we show that a Cu2O(1 1 1) surface with Cu vacancies has a lower free energy than the stoichiometric surface for the considered range of oxygen chemical potential and could be catalytically relevant.

Original languageEnglish
Pages (from-to)5809-5813
Number of pages5
JournalSurface Science
Volume601
Issue number24
DOIs
Publication statusPublished - 2007 Dec 15

Fingerprint

Oxides
Copper
Oxygen
copper
oxides
oxygen
Water gas shift
Chemical potential
Chemisorption
metastable state
chemisorption
Catalysis
Free energy
Vacancies
catalysis
Density functional theory
Chemical reactions
chemical reactions
free energy
Thermodynamics

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

Soon, Aloysius ; Todorova, Mira ; Delley, Bernard ; Stampfl, Catherine. / Surface oxides of the oxygen-copper system : Precursors to the bulk oxide phase?. In: Surface Science. 2007 ; Vol. 601, No. 24. pp. 5809-5813.
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Surface oxides of the oxygen-copper system : Precursors to the bulk oxide phase? / Soon, Aloysius; Todorova, Mira; Delley, Bernard; Stampfl, Catherine.

In: Surface Science, Vol. 601, No. 24, 15.12.2007, p. 5809-5813.

Research output: Contribution to journalArticle

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T2 - Precursors to the bulk oxide phase?

AU - Soon, Aloysius

AU - Todorova, Mira

AU - Delley, Bernard

AU - Stampfl, Catherine

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AB - To gain an initial understanding of the copper-based catalysts in commercially important chemical reactions such as the oxygen-assisted water-gas shift reaction, we performed density-functional theory calculations, investigating the interaction of oxygen and copper, focusing on the relative stability of surface oxides and oxide surfaces of the O/Cu system. By employing the technique of "ab initio atomistic thermodynamics", we show that surface oxides are only metastable at relevant pressures and temperatures of technical catalysis, with no stable chemisorption phase observed even at very low coverage. Although exhibiting only metastability, these surface oxides resemble the bulk oxide material both geometrically and electronically, and may serve as a precursor phase before onset of the bulk oxide phase. Having identified the bulk oxide as the most stable phase under realistic catalytic conditions, we show that a Cu2O(1 1 1) surface with Cu vacancies has a lower free energy than the stoichiometric surface for the considered range of oxygen chemical potential and could be catalytically relevant.

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