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Title: On the Importance of Metal–Oxide Interface Sites for the Water–Gas Shift Reaction Over Pt/CeO2 Catalysts

Abstract

The mechanism of water–gas shift reaction at the three-phase boundary of Pt/CeO2 catalysts has been investigated using density functional theory and microkinetic modeling to better understand the importance of metal–oxide interface sites in heterogeneous catalysis. Analysis of a microkinetic model based on parameters obtained from first principles suggests that both the “Redox pathway” and the “Associative carboxyl pathway with redox regeneration” could operate on Pt/CeO2 catalysts. Although (1) only few interfacial Pt atoms are found to be catalytically active at low temperatures due to strong adsorption of CO and (2) interfacial O–H bond breakage is difficult due to the high reducibility of ceria, interface sites are 2–3 orders of magnitude more active than Pt (1 1 1) and stepped Pt surface sites and therefore effectively determine the overall activity of Pt/CeO2. The high activity of Pt/CeO2 interface sites originates from a significantly enhanced water activation and dissociation at interfacial oxygen vacancies.

Authors:
; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1120082
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis, 309:314-324
Additional Journal Information:
Journal Name: Journal of Catalysis, 309:314-324
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Aranifard, Sara, Ammal, Salai Cheettu, and Heyden, Andreas. On the Importance of Metal–Oxide Interface Sites for the Water–Gas Shift Reaction Over Pt/CeO2 Catalysts. United States: N. p., 2014. Web. doi:10.1016/j.jcat.2013.10.012.
Aranifard, Sara, Ammal, Salai Cheettu, & Heyden, Andreas. On the Importance of Metal–Oxide Interface Sites for the Water–Gas Shift Reaction Over Pt/CeO2 Catalysts. United States. https://doi.org/10.1016/j.jcat.2013.10.012
Aranifard, Sara, Ammal, Salai Cheettu, and Heyden, Andreas. Wed . "On the Importance of Metal–Oxide Interface Sites for the Water–Gas Shift Reaction Over Pt/CeO2 Catalysts". United States. https://doi.org/10.1016/j.jcat.2013.10.012.
@article{osti_1120082,
title = {On the Importance of Metal–Oxide Interface Sites for the Water–Gas Shift Reaction Over Pt/CeO2 Catalysts},
author = {Aranifard, Sara and Ammal, Salai Cheettu and Heyden, Andreas},
abstractNote = {The mechanism of water–gas shift reaction at the three-phase boundary of Pt/CeO2 catalysts has been investigated using density functional theory and microkinetic modeling to better understand the importance of metal–oxide interface sites in heterogeneous catalysis. Analysis of a microkinetic model based on parameters obtained from first principles suggests that both the “Redox pathway” and the “Associative carboxyl pathway with redox regeneration” could operate on Pt/CeO2 catalysts. Although (1) only few interfacial Pt atoms are found to be catalytically active at low temperatures due to strong adsorption of CO and (2) interfacial O–H bond breakage is difficult due to the high reducibility of ceria, interface sites are 2–3 orders of magnitude more active than Pt (1 1 1) and stepped Pt surface sites and therefore effectively determine the overall activity of Pt/CeO2. The high activity of Pt/CeO2 interface sites originates from a significantly enhanced water activation and dissociation at interfacial oxygen vacancies.},
doi = {10.1016/j.jcat.2013.10.012},
url = {https://www.osti.gov/biblio/1120082}, journal = {Journal of Catalysis, 309:314-324},
number = ,
volume = ,
place = {United States},
year = {2014},
month = {1}
}