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Role of Water in Low-Temperature CO2 Reduction at Defect-Rich TiO2

Klimek, Justin ; Hallböök, Filip LU orcid ; Kruse, Niko ; Li, Fangliang ; Blomberg, Sara LU ; Al-Shamery, Katharina and Mohrhusen, Lars (2026) In Angewandte Chemie - International Edition 65(28).
Abstract

Point defects in titanium dioxide (TiO2) are the most relevant reaction sites for the activation of oxygenates. Herein, we probe the activation of CO2 on highly defective TiO2 in situ using synchrotron-based near-ambient pressure X-ray photoelectron spectroscopy between 0.1 mbar and 2.6 mbar from room temperature to 700 K. Multiple carbon surface intermediates form upon CO2 activation. The presence of key intermediates acts as a fingerprint for the population of different reaction pathways, that is, promotion or suppression of selected reaction steps in various gas environments. In the absence of potent H/OH donors, the formyl, glyoxal, formaldehyde and carbene pathways are populated... (More)

Point defects in titanium dioxide (TiO2) are the most relevant reaction sites for the activation of oxygenates. Herein, we probe the activation of CO2 on highly defective TiO2 in situ using synchrotron-based near-ambient pressure X-ray photoelectron spectroscopy between 0.1 mbar and 2.6 mbar from room temperature to 700 K. Multiple carbon surface intermediates form upon CO2 activation. The presence of key intermediates acts as a fingerprint for the population of different reaction pathways, that is, promotion or suppression of selected reaction steps in various gas environments. In the absence of potent H/OH donors, the formyl, glyoxal, formaldehyde and carbene pathways are populated simultaneously. However, aqueous atmospheres boost intermediate formation and promote oxygen-rich organic molecules, suppressing coke formation along the carbene pathway. Thermal loss of hydroxyls above ≈550 K triggers the population of such oxygen-lean routes, along with a decrease in carbon intermediates, converging to the chemistry under water-free conditions. Our results highlight reduced titania as a noble metal-free CO2 activation catalyst and demonstrate how water can be used to favor the desired product distribution. The findings herein will guide the development of sustainable catalysts from heavily reduced oxides, for example, black titania, for platform chemicals based on CO2 as a building block.

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Please use this url to cite or link to this publication:
author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
C1 building blocks, CO activation, defect chemistry, heterogeneous catalysis, near-ambient pressure X-ray photoelectron spectroscopy, titanium dioxide
in
Angewandte Chemie - International Edition
volume
65
issue
28
article number
e7574479
publisher
John Wiley & Sons Inc.
external identifiers
  • pmid:42126416
  • scopus:105038637246
ISSN
1433-7851
DOI
10.1002/anie.7574479
language
English
LU publication?
yes
id
ac164913-2f9c-4e45-8039-94aae23bac04
date added to LUP
2026-08-20 11:59:31
date last changed
2026-09-03 12:59:22
@article{ac164913-2f9c-4e45-8039-94aae23bac04,
  abstract     = {{<p>Point defects in titanium dioxide (TiO<sub>2</sub>) are the most relevant reaction sites for the activation of oxygenates. Herein, we probe the activation of CO<sub>2</sub> on highly defective TiO<sub>2</sub> in situ using synchrotron-based near-ambient pressure X-ray photoelectron spectroscopy between 0.1 mbar and 2.6 mbar from room temperature to 700 K. Multiple carbon surface intermediates form upon CO<sub>2</sub> activation. The presence of key intermediates acts as a fingerprint for the population of different reaction pathways, that is, promotion or suppression of selected reaction steps in various gas environments. In the absence of potent H/OH donors, the formyl, glyoxal, formaldehyde and carbene pathways are populated simultaneously. However, aqueous atmospheres boost intermediate formation and promote oxygen-rich organic molecules, suppressing coke formation along the carbene pathway. Thermal loss of hydroxyls above ≈550 K triggers the population of such oxygen-lean routes, along with a decrease in carbon intermediates, converging to the chemistry under water-free conditions. Our results highlight reduced titania as a noble metal-free CO<sub>2</sub> activation catalyst and demonstrate how water can be used to favor the desired product distribution. The findings herein will guide the development of sustainable catalysts from heavily reduced oxides, for example, black titania, for platform chemicals based on CO<sub>2</sub> as a building block.</p>}},
  author       = {{Klimek, Justin and Hallböök, Filip and Kruse, Niko and Li, Fangliang and Blomberg, Sara and Al-Shamery, Katharina and Mohrhusen, Lars}},
  issn         = {{1433-7851}},
  keywords     = {{C1 building blocks; CO activation; defect chemistry; heterogeneous catalysis; near-ambient pressure X-ray photoelectron spectroscopy; titanium dioxide}},
  language     = {{eng}},
  number       = {{28}},
  publisher    = {{John Wiley & Sons Inc.}},
  series       = {{Angewandte Chemie - International Edition}},
  title        = {{Role of Water in Low-Temperature CO<sub>2</sub> Reduction at Defect-Rich TiO<sub>2</sub>}},
  url          = {{http://dx.doi.org/10.1002/anie.7574479}},
  doi          = {{10.1002/anie.7574479}},
  volume       = {{65}},
  year         = {{2026}},
}