DFT studies of Cr(VI) complex adsorption on hydroxylated hematite (1 over(1, ̄) 0 2) surfaces

Shuxia Yin, D. E. Ellis*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

The adsorption structures of Cr(VI) species on hydroxylated α-Fe2O3(1 over(1, ̄) 0 2) were investigated using density functional theory within a periodic slab model. A broad structural survey of H2CrO4, HCrO4- and CrO42 - adsorbed on different surface sites was carried out. Chromate species adsorb on the hydroxylated surface via an outer-sphere mechanism through H-bonding and ion-dipole attraction. The most stable structure for H2CrO4 reveals strong H-bonding to surface and between adsorbates. For HCrO4-, a configuration that shows both H-bonding and Cr-O···H-O-Fe ion-dipole interaction is the most favored. In the case of CrO42 -, the most favored adsorption configuration shows the complex standing on the surface with a Cr-O bond aligned on OH, presenting the strongest Cr-O···H-O-Fe interaction. In these three species, CrO42 - displays the strongest interaction with the hydroxylated (1 over(1, ̄) 0 2) surface with no tendency toward reduction observed, in accordance with experiment.

Original languageEnglish (US)
Pages (from-to)736-746
Number of pages11
JournalSurface Science
Volume603
Issue number4
DOIs
StatePublished - Feb 15 2009

Keywords

  • (1 over(1, ̄) 0 2) surface
  • Adsorption mechanism
  • Chromate
  • Cr(VI)
  • Density functional theory
  • H-bonding
  • Hematite
  • Ion-dipole interaction

ASJC Scopus subject areas

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

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