Surface structure of catalytically-active ceria nanoparticles

Xing Huang, Matthew J. Beck

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Catalytic mechanisms, and therefore activity, depend on the structure of catalyst surfaces. In turn, surfaces may reconstruct and/or exhibit local configurations that vary from bulk composition and structure. CeO2 (ceria) is a redox catalyst of interest in numerous automotive, energy and, increasingly, biomedical applications. Previous studies aimed at understanding catalytic mechanisms on ceria have limited consideration to systems with bulk-like stoichiometric or sub-stoichiometric surfaces. Here we summarize previous computational studies on ceria surfaces, nanoclusters, and nanoparticles, and highlight challenges in constructing physically- representative ceria nanoparticle (CNP) structures. Setting aside assumptions of bulk-like stoichiometric or sub-stoichiometric ceria surface terminations, we report results of DFT + U calculations and show that sufficiently small CNPs are not bulk-terminated, but rather are stabilized by the formation of O xq groups (-2 ≤ q ≤ 0, x ≤ 3) at corners, edges, and {1 0 0} facets. These surface structures, not the annihilation and regeneration of O-vacancies, may directly control reduction/oxidation catalysis at CNPs below a critical size. As anion groups other than Ox q groups could be incorporated in stable CNP surfaces, this suggests the possibility of tailoring small CNP structures and mechanisms for particular catalytic reactions.

Original languageEnglish
Pages (from-to)122-133
Number of pages12
JournalComputational Materials Science
Volume91
DOIs
StatePublished - Aug 2014

Keywords

  • Ceria nanoparticles
  • Density functional theory
  • Surface structure

ASJC Scopus subject areas

  • Computer Science (all)
  • Chemistry (all)
  • Materials Science (all)
  • Mechanics of Materials
  • Physics and Astronomy (all)
  • Computational Mathematics

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