STM images of anionic defects at CeO2(111)-A theoretical perspective

Matthew J. Wolf, Christopher W.M. Castleton, Kersti Hermansson, Jolla Kullgren

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We present a theoretically oriented analysis of the appearance and properties of plausible candidates for the anionic defects observed in scanning tunneling microscopy (STM) experiments on CeO2(111). The simulations are based on density functional theory (DFT) and cover oxygen vacancies, fluorine impurities and hydroxyl groups in the surface and sub-surface layers. In the surface layer, all three appear as missing spots in the oxygen sublattice in filled state simulated STM images, but they are distinguishable in empty state images, where surface oxygen vacancies and hydroxyls appear as, respectively, diffuse and sharp bright features at oxygen sites, while fluorine defects appear as triangles of darkened Ce ions. In the sub-surface layer, all three defects present more complex patterns, with different combinations of brightened oxygen ion triangles and/or darkened Ce ion triangles, so we provide image maps to support experimental identification. We also discuss other properties that could be used to distinguish the defects, namely their diffusion rates and distributions.

Original languageEnglish
Article number212
JournalFrontiers in Chemistry
Volume7
Issue numberJUN
DOIs
Publication statusPublished - 6 Jun 2019

Keywords

  • Anionic defects
  • Cerium dioxide (CeO2)
  • Density functional theory
  • Reducible oxide
  • Simulated STM images

ASJC Scopus subject areas

  • Chemistry(all)

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