Surface water-assisted preferential CO oxidation on Pt/CeO2 catalyst

Olga Pozdnyakova-Tellinger, Detre Teschner, Jutta Kröhnert, Friederike C. Jentoft, Axel Knop-Gericke, Robert Schlögl, A. Wootsch

Research output: Contribution to journalArticle

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Abstract

The production of clean hydrogen is a key requirement for a future hydrogen economy, in general, and, specifically, for the application of proton exchange membrane fuel cells (PEMFC). Here, we focus on one of the essential purification methods, the so-called "PROX" reaction, the preferential oxidation of traces of CO in a large hydrogen excess. Small platinum particles on a reducible support like ceria are effective to remove CO from hydrogen feed. The paper specifically addresses the mechanism of the PROX reaction on a Pt/CeO 2 catalyst using in situ experimentation with time-resolved and temperature-programmed diffuse reflectance infrared spectroscopy. Surface species (carbonates, formates, carbonyls, hydroxyls, and adsorbed water) present under reaction conditions are identified, and correlations of their abundance with catalytic performance allow the discrimination between mechanistically relevant species (intermediates) and spectator species. The following scenario is proposed: hydrogen initially adsorbed on platinum spills over to the support, leading to ordered vacancy formation in the ceria bulk as well as hydroxylation and hydration of the surface. CO is mainly adsorbed in on-top orientation on metallic platinum. The linear relationship between the amount of adsorbed water (H2Oads) and the CO2 production indicates that the hydrated ceria supplies an oxidizing agent at the metal/support interface reacting with the nearby surface carbonyls on the Pt particles yielding CO 2. Moreover, adsorbed water also blocks hydrogen oxidation because of desorption hindrance. From the correlations in the presented results, an intelligent PROX catalyst can be formulated, providing a guideline for future developments.

Original languageEnglish
Pages (from-to)5426-5431
Number of pages6
JournalJournal of Physical Chemistry C
Volume111
Issue number14
DOIs
Publication statusPublished - Apr 12 2007

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Carbon Monoxide
surface water
Surface waters
Hydrogen
catalysts
Oxidation
oxidation
Catalysts
Cerium compounds
hydrogen
Platinum
platinum
Water
Formates
water
Hydroxylation
formates
experimentation
Hazardous materials spills
economy

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Pozdnyakova-Tellinger, O., Teschner, D., Kröhnert, J., Jentoft, F. C., Knop-Gericke, A., Schlögl, R., & Wootsch, A. (2007). Surface water-assisted preferential CO oxidation on Pt/CeO2 catalyst. Journal of Physical Chemistry C, 111(14), 5426-5431. https://doi.org/10.1021/jp0669862

Surface water-assisted preferential CO oxidation on Pt/CeO2 catalyst. / Pozdnyakova-Tellinger, Olga; Teschner, Detre; Kröhnert, Jutta; Jentoft, Friederike C.; Knop-Gericke, Axel; Schlögl, Robert; Wootsch, A.

In: Journal of Physical Chemistry C, Vol. 111, No. 14, 12.04.2007, p. 5426-5431.

Research output: Contribution to journalArticle

Pozdnyakova-Tellinger, O, Teschner, D, Kröhnert, J, Jentoft, FC, Knop-Gericke, A, Schlögl, R & Wootsch, A 2007, 'Surface water-assisted preferential CO oxidation on Pt/CeO2 catalyst', Journal of Physical Chemistry C, vol. 111, no. 14, pp. 5426-5431. https://doi.org/10.1021/jp0669862
Pozdnyakova-Tellinger O, Teschner D, Kröhnert J, Jentoft FC, Knop-Gericke A, Schlögl R et al. Surface water-assisted preferential CO oxidation on Pt/CeO2 catalyst. Journal of Physical Chemistry C. 2007 Apr 12;111(14):5426-5431. https://doi.org/10.1021/jp0669862
Pozdnyakova-Tellinger, Olga ; Teschner, Detre ; Kröhnert, Jutta ; Jentoft, Friederike C. ; Knop-Gericke, Axel ; Schlögl, Robert ; Wootsch, A. / Surface water-assisted preferential CO oxidation on Pt/CeO2 catalyst. In: Journal of Physical Chemistry C. 2007 ; Vol. 111, No. 14. pp. 5426-5431.
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