Adsorption and decomposition of NO on O-covered planar and faceted Ir(2 1 0)

Wenhua Chen, Alan L. Stottlemyer, Jingguang G. Chen, Payam Kaghazchi, Timo Jacob, Theodore E. Madey, Robert A. Bartynski

Research output: Contribution to journalArticlepeer-review

15 Scopus citations

Abstract

We report on the adsorption and decomposition of NO on O-covered planar Ir(2 1 0) and nanofaceted Ir(2 1 0) with variable facet sizes investigated using temperature programmed desorption (TPD), high-resolution electron energy loss spectroscopy (HREELS), and density functional theory (DFT). When pre-covered with up to 0.5 ML O, both planar and faceted Ir(2 1 0) exhibit unexpectedly high reactivity for NO decomposition. Upon increasing the oxygen coverage to 0.7 ML O, planar Ir(2 1 0) has little activity while faceted Ir(2 1 0) still remains active toward NO decomposition, although NO decomposition is completely inhibited when both surfaces are pre-covered by 1 ML O. NO molecularly adsorbs on O-covered Ir at 300 K. At low NO and oxygen coverage, NO adsorbs on the atop sites of planar Ir(2 1 0) while on the bridge and atop sites of faceted Ir(2 1 0) composed of (1 1 0) and {3 1 1} faces. No evidence for size effects in the decomposition of NO on O-covered faceted Ir(2 1 0) is observed for average facet size in the range 5-14 nm. Our findings should be of importance for development of Ir-based catalysts for NO decomposition under oxygen-rich conditions.

Original languageEnglish (US)
Pages (from-to)3136-3144
Number of pages9
JournalSurface Science
Volume603
Issue number20
DOIs
StatePublished - Oct 15 2009

All Science Journal Classification (ASJC) codes

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

Keywords

  • Adsorption
  • Decomposition
  • Faceting
  • Iridium
  • Nitric oxide
  • Oxygen

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