Experimental Proof of the Bifunctional Mechanism for the Hydrogen Oxidation in Alkaline Media

Realization of the hydrogen economy relies on effective hydrogen production, storage, and utilization. The slow kinetics of hydrogen evolution and oxidation reaction (HER/HOR) in alkaline media limits many practical applications involving hydrogen generation and utilization, and how to overcome this...

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Published inAngewandte Chemie Vol. 129; no. 49; pp. 15800 - 15804
Main Authors Li, Jingkun, Ghoshal, Shraboni, Bates, Michael K., Miller, Todd E, Davies, Veronica, Stavitski, Eli, Attenkofer, Klaus, Mukerjee, Sanjeev, Ma, Zi‐Feng, Jia, Qingying
Format Journal Article
LanguageEnglish
Published Weinheim Wiley Subscription Services, Inc 04.12.2017
Subjects
Catalysis
Catalysts
Chemistry
Electrochemistry
Elektrochemie
Elektrokatalyse
Hydrogen
Hydrogen evolution
Hydrogen production
Hydrogen storage
Hydrogen-based energy
Kinetics
Legierungen
Oxidation
Reaction kinetics
Reaktionsmechanismen
Ruthenium
Trägerkatalysatoren
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Summary:Realization of the hydrogen economy relies on effective hydrogen production, storage, and utilization. The slow kinetics of hydrogen evolution and oxidation reaction (HER/HOR) in alkaline media limits many practical applications involving hydrogen generation and utilization, and how to overcome this fundamental limitation remains debatable. Here we present a kinetic study of the HOR on representative catalytic systems in alkaline media. Electrochemical measurements show that the HOR rate of Pt‐Ru/C and Ru/C systems is decoupled to their hydrogen binding energy (HBE), challenging the current prevailing HBE mechanism. The alternative bifunctional mechanism is verified by combined electrochemical and in situ spectroscopic data, which provide convincing evidence for the presence of hydroxy groups on surface Ru sites in the HOR potential region and its key role in promoting the rate‐determining Volmer step. The conclusion presents important references for design and selection of HOR catalysts. Bifunktioneller Mechanismus: Der experimentelle Nachweis von auf Ru‐Oberflächen adsorbierten Hydroxygruppen im Potentialbereich der Wasserstoffoxidationsreaktion (HOR) stützt den bifunktionellen Mechanismus für die HOR‐Kinetik der Pt‐Ru/C‐ und Ru/C‐Katalysatoren in alkalischen Medien. Das Ergebnis liefert wichtige Hinweise für die Entwicklung und gezielte Auswahl von HOR‐Katalysatoren.
ISSN:0044-8249
1521-3757
DOI:10.1002/ange.201708484