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Persistence of Ce3+ species on the surface of ceria during redox cycling : a modulated chemical excitation investigation

Hachemi, C. ; Dib, H. ; Debbichi, M. ; Badawi, M. ; Eads, C. LU orcid ; Ibrahim, M. ; Loridant, S. ; Knudsen, J. LU ; Kaper, H. LU and Cardenas, L. (2025) In Physical Chemistry Chemical Physics 27(22). p.12069-12079
Abstract

Operando resonant photoelectron spectroscopy (RPES) combined with modulated chemical excitation revealed the dynamic evolution of Ce3+/Ce4+ redox states at the surface of CeO2 during the CO oxidation reaction. Using alternating CO and O2 pulses as chemically modulated signals, we monitored the surface states in the valence band region, unveiling the evolution of electronic structure during the catalytic process. The analysis with different gas flow ratios revealed that under CO-rich conditions (CO : O2 ≥ 1), only partial conversion from Ce3+ to Ce4+ occurred. In contrast, complete Ce3+ to Ce4+ conversion was achieved when pulsing... (More)

Operando resonant photoelectron spectroscopy (RPES) combined with modulated chemical excitation revealed the dynamic evolution of Ce3+/Ce4+ redox states at the surface of CeO2 during the CO oxidation reaction. Using alternating CO and O2 pulses as chemically modulated signals, we monitored the surface states in the valence band region, unveiling the evolution of electronic structure during the catalytic process. The analysis with different gas flow ratios revealed that under CO-rich conditions (CO : O2 ≥ 1), only partial conversion from Ce3+ to Ce4+ occurred. In contrast, complete Ce3+ to Ce4+ conversion was achieved when pulsing O2 into O2-rich environments. Furthermore, we find that intermediate oxygen species, such as peroxo and OH, impact the conversion of Ce3+ and Ce4+. These oxygenated species coexist between 330 °C and 360 °C in pure O2, while above 390 °C only OH groups remain stable on the ceria surface.

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; ; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Chemistry Chemical Physics
volume
27
issue
22
pages
11 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:105006779572
  • pmid:40424059
ISSN
1463-9076
DOI
10.1039/d5cp01283j
language
English
LU publication?
yes
id
c897e34e-2762-497e-889f-556bb9cfdb51
date added to LUP
2025-09-18 13:36:54
date last changed
2025-09-19 04:02:27
@article{c897e34e-2762-497e-889f-556bb9cfdb51,
  abstract     = {{<p>Operando resonant photoelectron spectroscopy (RPES) combined with modulated chemical excitation revealed the dynamic evolution of Ce<sup>3+</sup>/Ce<sup>4+</sup> redox states at the surface of CeO<sub>2</sub> during the CO oxidation reaction. Using alternating CO and O<sub>2</sub> pulses as chemically modulated signals, we monitored the surface states in the valence band region, unveiling the evolution of electronic structure during the catalytic process. The analysis with different gas flow ratios revealed that under CO-rich conditions (CO : O<sub>2</sub> ≥ 1), only partial conversion from Ce<sup>3+</sup> to Ce<sup>4+</sup> occurred. In contrast, complete Ce<sup>3+</sup> to Ce<sup>4+</sup> conversion was achieved when pulsing O<sub>2</sub> into O<sub>2</sub>-rich environments. Furthermore, we find that intermediate oxygen species, such as peroxo and OH, impact the conversion of Ce<sup>3+</sup> and Ce<sup>4+</sup>. These oxygenated species coexist between 330 °C and 360 °C in pure O<sub>2</sub>, while above 390 °C only OH groups remain stable on the ceria surface.</p>}},
  author       = {{Hachemi, C. and Dib, H. and Debbichi, M. and Badawi, M. and Eads, C. and Ibrahim, M. and Loridant, S. and Knudsen, J. and Kaper, H. and Cardenas, L.}},
  issn         = {{1463-9076}},
  language     = {{eng}},
  number       = {{22}},
  pages        = {{12069--12079}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Physical Chemistry Chemical Physics}},
  title        = {{Persistence of Ce<sup>3+</sup> species on the surface of ceria during redox cycling : a modulated chemical excitation investigation}},
  url          = {{http://dx.doi.org/10.1039/d5cp01283j}},
  doi          = {{10.1039/d5cp01283j}},
  volume       = {{27}},
  year         = {{2025}},
}