Fundamental insight into enhanced activity of Pd/CeO2 thin films in hydrogen oxidation reaction in alkaline media

Palladium supported on ceria (Pd/CeO2) has recently raised strong interest as an alternative catalyst to platinum on the anode electrode in anion exchange membrane fuel cells. Herein, we provide new insight into the enhanced activity of Pd/CeO2 in hydrogen oxidation reaction (HOR) in alkaline media....

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Published inJournal of materials chemistry. A, Materials for energy and sustainability Vol. 11; no. 30; pp. 16370 - 16382
Main Authors Luneau, Mathilde, Strandberg, Linnéa, Montserrat-Sisó, Gerard, Shokhen, Victor, Mohan, Roopathy, Grönbeck, Henrik, Wickman, Björn
Format Journal Article
LanguageEnglish
Published Cambridge Royal Society of Chemistry 02.08.2023
Subjects
Anion exchange
Anion exchanging
Catalysts
Cerium oxides
Electrochemical analysis
Electrochemistry
Fuel cells
Fuel technology
Heavy metals
Hydrogen
Intermediates
Noble metals
Oxidation
Palladium
Quartz crystal microbalance
Quartz crystals
Reaction intermediates
Thin films
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Summary:Palladium supported on ceria (Pd/CeO2) has recently raised strong interest as an alternative catalyst to platinum on the anode electrode in anion exchange membrane fuel cells. Herein, we provide new insight into the enhanced activity of Pd/CeO2 in hydrogen oxidation reaction (HOR) in alkaline media. Using well-defined model thin films, we show that Pd/CeO2 thin films lead to enhanced activity in HOR compared to pure Pd thin films. In situ characterization using electrochemical quartz crystal microbalance provide in-depth understanding of the role of CeO2. CeO2 leads to fundamental differences in adsorption and absorption of key reaction intermediates during HOR. In combination with characterization and theoretical calculations, Pd atoms embedded in CeO2 are shown to be present on the prepared thin films and active for hydrogen activation but are not able to bind CO during CO-stripping characterization. Finally, an estimation of the source of hydroxyl intermediates provided by CeO2 – which could be directly participating in the reaction – is presented herein. Fundamental understanding of the Pd–CeO2 interface in HOR opens new ways to reduce the amount of noble metals in alkaline fuel cells.
ISSN:2050-7488
2050-7496
DOI:10.1039/d3ta01879b