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Hydroxylation of an ultrathin Co3O4(111) film on Ir(100) studied by in situ ambient pressure XPS and DFT

Haunold, Thomas ; Anić, Krešimir ; Genest, Alexander ; Rameshan, Christoph ; Roiaz, Matteo ; Li, Hao ; Wicht, Thomas ; Knudsen, Jan LU and Rupprechter, Günther (2025) In Surface Science 751.
Abstract

In the present work, we have studied the interaction of water with spinel cobalt oxide (Co3O4), an effect which has been considered a major cause of its catalytic deactivation. Employing a Co3O4(111) model thin film grown on Ir(100) in (ultra)high vacuum, and ambient pressure X-ray photoelectron spectroscopy (APXPS), hydroxylation in 0.5 mbar H2O vapor at room temperature was monitored in real time. The surface hydroxyl (OH) coverage was determined via two different models based (i) on the termination of a pristine and OH-covered Co3O4(111) surface as derived from density functional theory (DFT) calculations, and (ii) on a homogeneous cobalt oxyhydroxide... (More)

In the present work, we have studied the interaction of water with spinel cobalt oxide (Co3O4), an effect which has been considered a major cause of its catalytic deactivation. Employing a Co3O4(111) model thin film grown on Ir(100) in (ultra)high vacuum, and ambient pressure X-ray photoelectron spectroscopy (APXPS), hydroxylation in 0.5 mbar H2O vapor at room temperature was monitored in real time. The surface hydroxyl (OH) coverage was determined via two different models based (i) on the termination of a pristine and OH-covered Co3O4(111) surface as derived from density functional theory (DFT) calculations, and (ii) on a homogeneous cobalt oxyhydroxide (CoO(OH)) overlayer. Langmuir pseudo-second-order kinetics were applied to characterize the OH evolution with time, suggesting two regimes of chemisorption at the mosaic-like Co3O4(111) film: (i) plateaus, which were quickly saturated by OH, followed by (ii) slow hydroxylation in the “cracks” of the thin film. H2O dissociation and OH formation, blocking exposed Co2+ ions and additionally consuming surface lattice oxygen, respectively, may thus account for catalyst deactivation by H2O traces in reactive feeds.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cobalt oxide, Density functional theory, In situ studies, Model catalysis, Photoelectron spectroscopy, Water
in
Surface Science
volume
751
article number
122618
publisher
Elsevier
external identifiers
  • scopus:85205564178
ISSN
0039-6028
DOI
10.1016/j.susc.2024.122618
language
English
LU publication?
yes
id
308b72f0-6d70-4638-a97b-ee9872a005c6
date added to LUP
2024-11-27 14:11:49
date last changed
2025-04-04 15:15:29
@article{308b72f0-6d70-4638-a97b-ee9872a005c6,
  abstract     = {{<p>In the present work, we have studied the interaction of water with spinel cobalt oxide (Co<sub>3</sub>O<sub>4</sub>), an effect which has been considered a major cause of its catalytic deactivation. Employing a Co<sub>3</sub>O<sub>4</sub>(111) model thin film grown on Ir(100) in (ultra)high vacuum, and ambient pressure X-ray photoelectron spectroscopy (APXPS), hydroxylation in 0.5 mbar H<sub>2</sub>O vapor at room temperature was monitored in real time. The surface hydroxyl (OH) coverage was determined via two different models based (i) on the termination of a pristine and OH-covered Co<sub>3</sub>O<sub>4</sub>(111) surface as derived from density functional theory (DFT) calculations, and (ii) on a homogeneous cobalt oxyhydroxide (CoO(OH)) overlayer. Langmuir pseudo-second-order kinetics were applied to characterize the OH evolution with time, suggesting two regimes of chemisorption at the mosaic-like Co<sub>3</sub>O<sub>4</sub>(111) film: (i) plateaus, which were quickly saturated by OH, followed by (ii) slow hydroxylation in the “cracks” of the thin film. H<sub>2</sub>O dissociation and OH formation, blocking exposed Co<sup>2+</sup> ions and additionally consuming surface lattice oxygen, respectively, may thus account for catalyst deactivation by H<sub>2</sub>O traces in reactive feeds.</p>}},
  author       = {{Haunold, Thomas and Anić, Krešimir and Genest, Alexander and Rameshan, Christoph and Roiaz, Matteo and Li, Hao and Wicht, Thomas and Knudsen, Jan and Rupprechter, Günther}},
  issn         = {{0039-6028}},
  keywords     = {{Cobalt oxide; Density functional theory; In situ studies; Model catalysis; Photoelectron spectroscopy; Water}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Surface Science}},
  title        = {{Hydroxylation of an ultrathin Co<sub>3</sub>O<sub>4</sub>(111) film on Ir(100) studied by in situ ambient pressure XPS and DFT}},
  url          = {{http://dx.doi.org/10.1016/j.susc.2024.122618}},
  doi          = {{10.1016/j.susc.2024.122618}},
  volume       = {{751}},
  year         = {{2025}},
}