Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O(2) Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy

[Image: see text] We have used grazing incidence X-ray absorption fine structure spectroscopy at the cobalt K-edge to characterize monolayer CoO films on Pt(111) under ambient pressure exposure to CO and O(2), with the aim of identifying the Co phases present and their transformations under oxidizin...

Descripción completa

Detalles Bibliográficos
Autores principales: Gajdek, Dorotea, Olsson, Pär A. T., Blomberg, Sara, Gustafson, Johan, Carlsson, Per-Anders, Haase, Dörthe, Lundgren, Edvin, Merte, Lindsay R.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2022
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8883796/
https://www.ncbi.nlm.nih.gov/pubmed/35242268
http://dx.doi.org/10.1021/acs.jpcc.1c10284
_version_ 1784660023917412352
author Gajdek, Dorotea
Olsson, Pär A. T.
Blomberg, Sara
Gustafson, Johan
Carlsson, Per-Anders
Haase, Dörthe
Lundgren, Edvin
Merte, Lindsay R.
author_facet Gajdek, Dorotea
Olsson, Pär A. T.
Blomberg, Sara
Gustafson, Johan
Carlsson, Per-Anders
Haase, Dörthe
Lundgren, Edvin
Merte, Lindsay R.
author_sort Gajdek, Dorotea
collection PubMed
description [Image: see text] We have used grazing incidence X-ray absorption fine structure spectroscopy at the cobalt K-edge to characterize monolayer CoO films on Pt(111) under ambient pressure exposure to CO and O(2), with the aim of identifying the Co phases present and their transformations under oxidizing and reducing conditions. X-ray absorption near edge structure (XANES) spectra show clear changes in the chemical state of Co, with the 2+ state predominant under CO exposure and the 3+ state predominant under O(2)-rich conditions. Extended X-ray absorption fine structure spectroscopy (EXAFS) analysis shows that the CoO bilayer characterized in ultrahigh vacuum is not formed under the conditions used in this study. Instead, the spectra acquired at low temperatures suggest formation of cobalt hydroxide and oxyhydroxide. At higher temperatures, the spectra indicate dewetting of the film and suggest formation of bulklike Co(3)O(4) under oxidizing conditions. The experiments demonstrate the power of hard X-ray spectroscopy to probe the structures of well-defined oxide monolayers on metal single crystals under realistic catalytic conditions.
format Online
Article
Text
id pubmed-8883796
institution National Center for Biotechnology Information
language English
publishDate 2022
publisher American Chemical Society
record_format MEDLINE/PubMed
spelling pubmed-88837962022-03-01 Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O(2) Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy Gajdek, Dorotea Olsson, Pär A. T. Blomberg, Sara Gustafson, Johan Carlsson, Per-Anders Haase, Dörthe Lundgren, Edvin Merte, Lindsay R. J Phys Chem C Nanomater Interfaces [Image: see text] We have used grazing incidence X-ray absorption fine structure spectroscopy at the cobalt K-edge to characterize monolayer CoO films on Pt(111) under ambient pressure exposure to CO and O(2), with the aim of identifying the Co phases present and their transformations under oxidizing and reducing conditions. X-ray absorption near edge structure (XANES) spectra show clear changes in the chemical state of Co, with the 2+ state predominant under CO exposure and the 3+ state predominant under O(2)-rich conditions. Extended X-ray absorption fine structure spectroscopy (EXAFS) analysis shows that the CoO bilayer characterized in ultrahigh vacuum is not formed under the conditions used in this study. Instead, the spectra acquired at low temperatures suggest formation of cobalt hydroxide and oxyhydroxide. At higher temperatures, the spectra indicate dewetting of the film and suggest formation of bulklike Co(3)O(4) under oxidizing conditions. The experiments demonstrate the power of hard X-ray spectroscopy to probe the structures of well-defined oxide monolayers on metal single crystals under realistic catalytic conditions. American Chemical Society 2022-02-16 2022-02-24 /pmc/articles/PMC8883796/ /pubmed/35242268 http://dx.doi.org/10.1021/acs.jpcc.1c10284 Text en © 2022 The Authors. Published by American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Gajdek, Dorotea
Olsson, Pär A. T.
Blomberg, Sara
Gustafson, Johan
Carlsson, Per-Anders
Haase, Dörthe
Lundgren, Edvin
Merte, Lindsay R.
Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O(2) Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy
title Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O(2) Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy
title_full Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O(2) Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy
title_fullStr Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O(2) Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy
title_full_unstemmed Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O(2) Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy
title_short Structural Changes in Monolayer Cobalt Oxides under Ambient Pressure CO and O(2) Studied by In Situ Grazing-Incidence X-ray Absorption Fine Structure Spectroscopy
title_sort structural changes in monolayer cobalt oxides under ambient pressure co and o(2) studied by in situ grazing-incidence x-ray absorption fine structure spectroscopy
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8883796/
https://www.ncbi.nlm.nih.gov/pubmed/35242268
http://dx.doi.org/10.1021/acs.jpcc.1c10284
work_keys_str_mv AT gajdekdorotea structuralchangesinmonolayercobaltoxidesunderambientpressurecoando2studiedbyinsitugrazingincidencexrayabsorptionfinestructurespectroscopy
AT olssonparat structuralchangesinmonolayercobaltoxidesunderambientpressurecoando2studiedbyinsitugrazingincidencexrayabsorptionfinestructurespectroscopy
AT blombergsara structuralchangesinmonolayercobaltoxidesunderambientpressurecoando2studiedbyinsitugrazingincidencexrayabsorptionfinestructurespectroscopy
AT gustafsonjohan structuralchangesinmonolayercobaltoxidesunderambientpressurecoando2studiedbyinsitugrazingincidencexrayabsorptionfinestructurespectroscopy
AT carlssonperanders structuralchangesinmonolayercobaltoxidesunderambientpressurecoando2studiedbyinsitugrazingincidencexrayabsorptionfinestructurespectroscopy
AT haasedorthe structuralchangesinmonolayercobaltoxidesunderambientpressurecoando2studiedbyinsitugrazingincidencexrayabsorptionfinestructurespectroscopy
AT lundgrenedvin structuralchangesinmonolayercobaltoxidesunderambientpressurecoando2studiedbyinsitugrazingincidencexrayabsorptionfinestructurespectroscopy
AT mertelindsayr structuralchangesinmonolayercobaltoxidesunderambientpressurecoando2studiedbyinsitugrazingincidencexrayabsorptionfinestructurespectroscopy