Structure sensitivity in the oxidation of CO on Ir surfaces

Wenhua Chen, Ivan Ermanoski, Timo Jacob, Theodore E. Madey

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

We report results on the catalytic oxidation of carbon monoxide (CO) over clean Ir surfaces that are prepared reversibly from the same crystal in situ with different surface morphologies, from planar to nanometer-scale facets of specific crystal orientations and various sizes. Our temperature-programmed desorption (TPD) data show that both planar Ir(210) and faceted Ir(210) are very active for CO oxidation to form CO 2. Preadsorbed oxygen promotes the oxidation of CO, whereas high coverages of preadsorbed CO poison the reaction by blocking the surface sites for oxygen adsorption. At low coverages of preadsorbed oxygen (≤0.3 ML of O), the temperature 71 for the onset of CO 2 desorption decreases with increasing CO coverage. At high coverages of preadsorbed oxygen (>0.5 ML of O), T i is <330 K and is independent of CO coverage. Moreover, we find clear evidence for structure sensitivity in CO oxidation over clean planar Ir(210) versus that over clean faceted Ir(210): the CO 2 desorption rate is sensitive to the surface morphological differences. However, no evidence has been found for size effects in CO oxidation over faceted Ir(210) for average facet size ranging from 5 to 14 nm. Energetically favorable binding sites for O/Ir(210) are characterized using density functional theory (DFT) calculations.

Original languageEnglish (US)
Pages (from-to)3166-3173
Number of pages8
JournalLangmuir
Volume22
Issue number7
DOIs
StatePublished - Mar 28 2006
Externally publishedYes

Fingerprint

Carbon Monoxide
Carbon monoxide
carbon monoxide
Oxidation
oxidation
sensitivity
Oxygen
desorption
oxygen
flat surfaces
Desorption
poisons
Catalytic oxidation
Poisons
Binding sites
Temperature programmed desorption
Crystal orientation
crystals
Density functional theory
Surface morphology

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Structure sensitivity in the oxidation of CO on Ir surfaces. / Chen, Wenhua; Ermanoski, Ivan; Jacob, Timo; Madey, Theodore E.

In: Langmuir, Vol. 22, No. 7, 28.03.2006, p. 3166-3173.

Research output: Contribution to journalArticle

Chen, Wenhua ; Ermanoski, Ivan ; Jacob, Timo ; Madey, Theodore E. / Structure sensitivity in the oxidation of CO on Ir surfaces. In: Langmuir. 2006 ; Vol. 22, No. 7. pp. 3166-3173.
@article{cd57016b31654aba9d94113575ba6170,
title = "Structure sensitivity in the oxidation of CO on Ir surfaces",
abstract = "We report results on the catalytic oxidation of carbon monoxide (CO) over clean Ir surfaces that are prepared reversibly from the same crystal in situ with different surface morphologies, from planar to nanometer-scale facets of specific crystal orientations and various sizes. Our temperature-programmed desorption (TPD) data show that both planar Ir(210) and faceted Ir(210) are very active for CO oxidation to form CO 2. Preadsorbed oxygen promotes the oxidation of CO, whereas high coverages of preadsorbed CO poison the reaction by blocking the surface sites for oxygen adsorption. At low coverages of preadsorbed oxygen (≤0.3 ML of O), the temperature 71 for the onset of CO 2 desorption decreases with increasing CO coverage. At high coverages of preadsorbed oxygen (>0.5 ML of O), T i is <330 K and is independent of CO coverage. Moreover, we find clear evidence for structure sensitivity in CO oxidation over clean planar Ir(210) versus that over clean faceted Ir(210): the CO 2 desorption rate is sensitive to the surface morphological differences. However, no evidence has been found for size effects in CO oxidation over faceted Ir(210) for average facet size ranging from 5 to 14 nm. Energetically favorable binding sites for O/Ir(210) are characterized using density functional theory (DFT) calculations.",
author = "Wenhua Chen and Ivan Ermanoski and Timo Jacob and Madey, {Theodore E.}",
year = "2006",
month = "3",
day = "28",
doi = "10.1021/la053183h",
language = "English (US)",
volume = "22",
pages = "3166--3173",
journal = "Langmuir",
issn = "0743-7463",
publisher = "American Chemical Society",
number = "7",

}

TY - JOUR

T1 - Structure sensitivity in the oxidation of CO on Ir surfaces

AU - Chen, Wenhua

AU - Ermanoski, Ivan

AU - Jacob, Timo

AU - Madey, Theodore E.

PY - 2006/3/28

Y1 - 2006/3/28

N2 - We report results on the catalytic oxidation of carbon monoxide (CO) over clean Ir surfaces that are prepared reversibly from the same crystal in situ with different surface morphologies, from planar to nanometer-scale facets of specific crystal orientations and various sizes. Our temperature-programmed desorption (TPD) data show that both planar Ir(210) and faceted Ir(210) are very active for CO oxidation to form CO 2. Preadsorbed oxygen promotes the oxidation of CO, whereas high coverages of preadsorbed CO poison the reaction by blocking the surface sites for oxygen adsorption. At low coverages of preadsorbed oxygen (≤0.3 ML of O), the temperature 71 for the onset of CO 2 desorption decreases with increasing CO coverage. At high coverages of preadsorbed oxygen (>0.5 ML of O), T i is <330 K and is independent of CO coverage. Moreover, we find clear evidence for structure sensitivity in CO oxidation over clean planar Ir(210) versus that over clean faceted Ir(210): the CO 2 desorption rate is sensitive to the surface morphological differences. However, no evidence has been found for size effects in CO oxidation over faceted Ir(210) for average facet size ranging from 5 to 14 nm. Energetically favorable binding sites for O/Ir(210) are characterized using density functional theory (DFT) calculations.

AB - We report results on the catalytic oxidation of carbon monoxide (CO) over clean Ir surfaces that are prepared reversibly from the same crystal in situ with different surface morphologies, from planar to nanometer-scale facets of specific crystal orientations and various sizes. Our temperature-programmed desorption (TPD) data show that both planar Ir(210) and faceted Ir(210) are very active for CO oxidation to form CO 2. Preadsorbed oxygen promotes the oxidation of CO, whereas high coverages of preadsorbed CO poison the reaction by blocking the surface sites for oxygen adsorption. At low coverages of preadsorbed oxygen (≤0.3 ML of O), the temperature 71 for the onset of CO 2 desorption decreases with increasing CO coverage. At high coverages of preadsorbed oxygen (>0.5 ML of O), T i is <330 K and is independent of CO coverage. Moreover, we find clear evidence for structure sensitivity in CO oxidation over clean planar Ir(210) versus that over clean faceted Ir(210): the CO 2 desorption rate is sensitive to the surface morphological differences. However, no evidence has been found for size effects in CO oxidation over faceted Ir(210) for average facet size ranging from 5 to 14 nm. Energetically favorable binding sites for O/Ir(210) are characterized using density functional theory (DFT) calculations.

UR - http://www.scopus.com/inward/record.url?scp=33645529891&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33645529891&partnerID=8YFLogxK

U2 - 10.1021/la053183h

DO - 10.1021/la053183h

M3 - Article

VL - 22

SP - 3166

EP - 3173

JO - Langmuir

JF - Langmuir

SN - 0743-7463

IS - 7

ER -