DFT study of oxidation states on pyrite surface sites

Tamás Rozgonyi, András Stirling

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17 Citations (Scopus)

Abstract

Density functional calculations have been performed to study the interaction of oxygen with clean and defective pyrite (100) surfaces. Molecular adsorption states are predicted to undergo dissociation because atomic chemisorption is far more favorable thermodynamically for all surfaces. On the defect-free FeS2 surface molecular adsorption takes place on neighboring iron sites in a side-on fashion. S-adatoms react weakly with O2, whereas S-vacancies bind very strongly to molecular oxygen. Dissociative chemisorption on a clean surface prefers the sulfur atoms to iron in sharp contrast to water adsorption. Reaction with atomic oxygen is thermodynamically preferred on the defect sites when they are available. Oxidation can fully eliminate the S-adatom sites by SO2 formation. The most favorable sites for oxidation are sulfur vacancies where O atoms can occupy the missing sulfur sites. The predicted oxidation states and their relative stabilities are in agreement with experiments and expected to assist the interpretation of X-ray photoelectron spectroscopy (XPS) measurements.

Original languageEnglish
Pages (from-to)7704-7710
Number of pages7
JournalJournal of Physical Chemistry C
Volume119
Issue number14
DOIs
Publication statusPublished - Apr 9 2015

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ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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