Evidence of Mars­Van­Krevelen Mechanism in the Electrochemical Oxygen Evolution on Ni Based Catalysts

Title
Evidence of Mars­Van­Krevelen Mechanism in the Electrochemical Oxygen Evolution on Ni Based Catalysts
Authors
오형석Jorge Ferreira de AraujoFabio DionigiThomas MerzdorfPeter Strasser
Keywords
Alkaline OER Catalyst; Differential Electrochemical Mass Spectrometry; Isotope 18O; Lattice Oxygen Evolution
Issue Date
2021-04
Publisher
Angewandte Chemie international edition
Citation
VOL 게재예정, 게제예정
Abstract
Water oxidation is a crucial reaction for renewable energy conversion and storage. Among the alkaline oxygen evolution reaction (OER) catalysts, NiFe based oxyhydroxides show the highest catalytic activity. However, the details of their OER mechanism are still unclear, due to the elusive nature of the OER intermediates. Here by using a novel differential electrochemical mass spectrometry (DEMS) cell interface, we performed water isotope-labelled experiments in 18O-labelled alkaline electrolyte on Ni(OH)2 and NiFe layered double hydroxide nanocatalysts. Our experiments confirm the occurrence of Mars-van-Krevelen lattice oxygen evolution reaction mechanism in both catalysts to various degrees, which involves the coupling of oxygen atoms from the catalyst and the electrolyte. The quantitative charge analysis suggests that the participating lattice oxygen atoms belong exclusively to the catalyst surface, confirming DFT computational hypotheses. Also, DEMS data suggest a fundamental correlation between the magnitude of the lattice oxygen mechanism and the faradaic efficiency of oxygen controlled by pseudocapacitive oxidative metal redox charges.
URI
http://pubs.kist.re.kr/handle/201004/73068
ISSN
1433-7851
Appears in Collections:
KIST Publication > Article
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