Water-assisted generation of catalytic interface: The case of interfacial Pt-FeOx(OH)y sites active in preferential carbon monoxide oxidation

Ilia I. Sadykov, Dennis Palagin, Frank Krumeich, Igor V. Plokhikh, Jeroen A. van Bokhoven, Maarten Nachtegaal, Olga V. Safonova*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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Abstract

The surface of supported heterogeneous catalysts often contains adsorbed water and hydroxyl groups even when water is not directly added to the reaction stream. Nonetheless, the reactivity of adsorbed water and hydroxyl groups is rarely considered. We demonstrate that water and hydroxyl groups can not only directly participate in the catalytic oxidation processes but are also able to generate and stabilize the catalytically active metal-oxide interface. We show that the reduction of Pt-Fe-supported catalysts with hydrogen in the presence of adsorbed water or steam allows for achieving one of the highest preferential carbon monoxide oxidation activities at ambient temperature. These conditions create active iron-associated hydroxyl groups next to platinum nanoparticles with enhanced reactivity towards carbon monoxide oxidation. Density functional theory calculations suggest that hydroxylation of oxidic iron species stabilizes the FeOx(OH)y/Pt interface, via strong metal-support interaction, which is confirmed by chemisorption measurements. Kinetic experiments, including those with 18O-labeled water, in combination with operando infrared spectroscopy, show that water and hydroxyl groups directly participate in preferential carbon monoxide oxidation. A quantitative correlation between the catalytic activity of Pt-FeOx(OH)y/γ-Al2O3 catalysts and the Fe2+ concentration, obtained using operando X-ray absorption spectroscopy, shows that the number of active Fe2+ sites and the carbon monoxide oxidation rate per active site can be significantly increased by water-assisted pretreatment with hydrogen. This work provides a new example of positive role of strong metal-support interaction for the design of more active catalysts.

Original languageEnglish
Article number115263
Number of pages11
JournalJournal of Catalysis
Volume429
DOIs
Publication statusPublished - 2024

Funding

We would like to extend our gratitude to the Swiss National Science Foundation for funding this research (Project 200021_179132). We thank Dr. Davide Ferri for providing the cell and his help during operando DRIFTS experiments. We are grateful to Dr. Alexey Fedorov and Evgenia Kountoupi for their help with chemisorption measurements. We thank Dr. Luca Artiglia and Xiansheng Li for the help with the XPS measurements. Many thanks to Prof. Dr. Gunnar Jeschke and Sergei Kuzin for the EPR measurements. We are grateful to the people who helped with operando experiments: Dr. Adam H. Clark, Dr. Miren Agote Arán, Dr. Anna Zabilska, Dr. Mikalai Artsiusheuski, Luca Maggiulli, Dr. Maneka Claire Roger, Filippo Buttignol, Jan Alfke, Patrick Gäumann, Sumant Phadke, and Lunhan Chen. The allocation of beamtime at the SuperXAS beamline at the Swiss Light Source is appreciatively acknowledged. The help of the Scientific Center for Optical and Electron Microscopy at ETH Zürich is gratefully acknowledged. The authors acknowledge the use of computational resources of DelftBlue supercomputer, provided by Delft High Performance Computing Centre.

Keywords

  • Catalytic interface
  • Infrared spectroscopy
  • Operando
  • Preferential CO oxidation
  • Pt-Fe
  • Role of water
  • Structure-activity relationship
  • X-ray absorption spectroscopy

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