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Pressure-controlled oxygen activation at single metal atom sites in a manganese–cobalt coordination network on graphene : from triplet–singlet spin transition to superoxo dissociation

Yadav, Asha ; Baronio, Stefania ; De Col, Michela ; Comini, Danilo ; Mischke, Valentin ; Namar, Alessandro ; Vinogradov, Nikolay LU orcid ; Scardamaglia, Mattia LU ; Cinchetti, Mirko and Zamborlini, Giovanni , et al. (2026) In Nanoscale
Abstract

Molecular oxygen activation at single transition metal atom sites is critical for catalysis but remains challenging to control. Here we investigate a manganese–cobalt bi-metallic coordination network on graphene, where Co(i) atoms are tetracoordinated by nitrogen. Combining density functional theory with in situ infrared-visible sum-frequency generation and ambient-pressure X-ray photoelectron spectroscopy, we demonstrate pressure-dependent oxygen ligation at Co sites. Below 10−6 mbar, O2 binds reversibly in a horizontal configuration, inducing charge transfer and a triplet-to-singlet spin transition characteristic of an active superoxo O2δ− species. Increasing oxygen pressure leads to... (More)

Molecular oxygen activation at single transition metal atom sites is critical for catalysis but remains challenging to control. Here we investigate a manganese–cobalt bi-metallic coordination network on graphene, where Co(i) atoms are tetracoordinated by nitrogen. Combining density functional theory with in situ infrared-visible sum-frequency generation and ambient-pressure X-ray photoelectron spectroscopy, we demonstrate pressure-dependent oxygen ligation at Co sites. Below 10−6 mbar, O2 binds reversibly in a horizontal configuration, inducing charge transfer and a triplet-to-singlet spin transition characteristic of an active superoxo O2δ− species. Increasing oxygen pressure leads to O2 dissociation, with atomic oxygen accumulating at Co(ii) sites and at the support. Co-exposure to O2 and CO enables room-temperature oxidation of the latter, preventing catalyst poisoning. These findings reveal how coordination and environmental control tune spin, oxidation state, and reactivity at single metal atoms, offering pathways for rational design of atomically precise two-dimensional catalysts.

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publication status
epub
subject
in
Nanoscale
publisher
Royal Society of Chemistry
external identifiers
  • scopus:105032561649
  • pmid:41815059
ISSN
2040-3364
DOI
10.1039/d5nr04824a
language
English
LU publication?
yes
id
43282860-c8df-4775-84a0-92c880c04da3
date added to LUP
2026-04-23 14:58:56
date last changed
2026-06-04 17:46:30
@article{43282860-c8df-4775-84a0-92c880c04da3,
  abstract     = {{<p>Molecular oxygen activation at single transition metal atom sites is critical for catalysis but remains challenging to control. Here we investigate a manganese–cobalt bi-metallic coordination network on graphene, where Co(i) atoms are tetracoordinated by nitrogen. Combining density functional theory with in situ infrared-visible sum-frequency generation and ambient-pressure X-ray photoelectron spectroscopy, we demonstrate pressure-dependent oxygen ligation at Co sites. Below 10<sup>−6</sup> mbar, O<sub>2</sub> binds reversibly in a horizontal configuration, inducing charge transfer and a triplet-to-singlet spin transition characteristic of an active superoxo O<sub>2</sub><sup>δ−</sup> species. Increasing oxygen pressure leads to O<sub>2</sub> dissociation, with atomic oxygen accumulating at Co(ii) sites and at the support. Co-exposure to O<sub>2</sub> and CO enables room-temperature oxidation of the latter, preventing catalyst poisoning. These findings reveal how coordination and environmental control tune spin, oxidation state, and reactivity at single metal atoms, offering pathways for rational design of atomically precise two-dimensional catalysts.</p>}},
  author       = {{Yadav, Asha and Baronio, Stefania and De Col, Michela and Comini, Danilo and Mischke, Valentin and Namar, Alessandro and Vinogradov, Nikolay and Scardamaglia, Mattia and Cinchetti, Mirko and Zamborlini, Giovanni and Giannozzi, Paolo and Vesselli, Erik}},
  issn         = {{2040-3364}},
  language     = {{eng}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Nanoscale}},
  title        = {{Pressure-controlled oxygen activation at single metal atom sites in a manganese–cobalt coordination network on graphene : from triplet–singlet spin transition to superoxo dissociation}},
  url          = {{http://dx.doi.org/10.1039/d5nr04824a}},
  doi          = {{10.1039/d5nr04824a}},
  year         = {{2026}},
}