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Dynamic Behavior of Tin at Platinum Surfaces during Catalytic CO Oxidation

Wallander, Harald J. LU ; Gajdek, Dorotea LU ; Albertin, Stefano LU ; Harlow, Gary LU ; Braud, Nicolas ; Buß, Lars ; Krisponeit, Jon Olaf ; Flege, Jan Ingo ; Falta, Jens and Lundgren, Edvin LU , et al. (2023) In ACS Catalysis 13(24). p.16158-16167
Abstract

Platinum-tin surfaces are active for CO oxidation, but their activity and the effects of tin oxide phases that form under reaction conditions are poorly understood. We have studied surface alloys of tin prepared on platinum single crystals during catalytic CO oxidation using near-ambient-pressure X-ray photoemission spectroscopy. On the flat terraces of Sn/Pt(111), a wetting layer of Sn(II) surface oxide forms, while on the stepped Sn/Pt(223) surface, 3D clusters of Sn(IV) oxide are formed. Oxidation of tin by O2 competes with the reduction of the oxides by CO under reaction conditions. Oxides that do not completely cover the surface can be reduced to metallic tin, while a fully covering layer of Sn(II) oxide cannot, showing... (More)

Platinum-tin surfaces are active for CO oxidation, but their activity and the effects of tin oxide phases that form under reaction conditions are poorly understood. We have studied surface alloys of tin prepared on platinum single crystals during catalytic CO oxidation using near-ambient-pressure X-ray photoemission spectroscopy. On the flat terraces of Sn/Pt(111), a wetting layer of Sn(II) surface oxide forms, while on the stepped Sn/Pt(223) surface, 3D clusters of Sn(IV) oxide are formed. Oxidation of tin by O2 competes with the reduction of the oxides by CO under reaction conditions. Oxides that do not completely cover the surface can be reduced to metallic tin, while a fully covering layer of Sn(II) oxide cannot, showing the importance of oxide edge sites for the reduction process. The samples where 2D oxide layers are formed show a higher CO oxidation activity than for pure platinum at low temperatures, while the Sn(IV) oxide clusters on the stepped surfaces do not affect the measured CO oxidation rate. We therefore identify 2D Sn(II) oxide as an active phase for CO oxidation. While oxide island edges appear to make only minor contributions to conversion under these conditions, reactions at these sites play a major role in determining the phases present and their transformations.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
alloys, CO oxidation, operando, oxides, platinum, stepped surfaces, tin
in
ACS Catalysis
volume
13
issue
24
pages
10 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85180109984
ISSN
2155-5435
DOI
10.1021/acscatal.3c04657
language
English
LU publication?
yes
id
9ac541df-67ff-4c3e-9226-2e1fb98665e8
date added to LUP
2024-01-10 11:03:35
date last changed
2024-02-09 11:20:46
@article{9ac541df-67ff-4c3e-9226-2e1fb98665e8,
  abstract     = {{<p>Platinum-tin surfaces are active for CO oxidation, but their activity and the effects of tin oxide phases that form under reaction conditions are poorly understood. We have studied surface alloys of tin prepared on platinum single crystals during catalytic CO oxidation using near-ambient-pressure X-ray photoemission spectroscopy. On the flat terraces of Sn/Pt(111), a wetting layer of Sn(II) surface oxide forms, while on the stepped Sn/Pt(223) surface, 3D clusters of Sn(IV) oxide are formed. Oxidation of tin by O<sub>2</sub> competes with the reduction of the oxides by CO under reaction conditions. Oxides that do not completely cover the surface can be reduced to metallic tin, while a fully covering layer of Sn(II) oxide cannot, showing the importance of oxide edge sites for the reduction process. The samples where 2D oxide layers are formed show a higher CO oxidation activity than for pure platinum at low temperatures, while the Sn(IV) oxide clusters on the stepped surfaces do not affect the measured CO oxidation rate. We therefore identify 2D Sn(II) oxide as an active phase for CO oxidation. While oxide island edges appear to make only minor contributions to conversion under these conditions, reactions at these sites play a major role in determining the phases present and their transformations.</p>}},
  author       = {{Wallander, Harald J. and Gajdek, Dorotea and Albertin, Stefano and Harlow, Gary and Braud, Nicolas and Buß, Lars and Krisponeit, Jon Olaf and Flege, Jan Ingo and Falta, Jens and Lundgren, Edvin and Merte, Lindsay R.}},
  issn         = {{2155-5435}},
  keywords     = {{alloys; CO oxidation; operando; oxides; platinum; stepped surfaces; tin}},
  language     = {{eng}},
  number       = {{24}},
  pages        = {{16158--16167}},
  publisher    = {{The American Chemical Society (ACS)}},
  series       = {{ACS Catalysis}},
  title        = {{Dynamic Behavior of Tin at Platinum Surfaces during Catalytic CO Oxidation}},
  url          = {{http://dx.doi.org/10.1021/acscatal.3c04657}},
  doi          = {{10.1021/acscatal.3c04657}},
  volume       = {{13}},
  year         = {{2023}},
}