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Main Title: Uncovering the prominent role of metal ions in octahedral versus tetrahedral sites of cobalt-zinc oxide catalysts for efficient oxidation of water
Author(s): Menezes, Prashanth W.
Indra, Arindam
Bergmann, Arno
Chernev, Petko
Walter, Carsten
Dau, Holger
Strasser, Peter
Drieß, Matthias
Type: Article
Language Code: en
Abstract: The fabrication and design of earth-abundant and high-performance catalysts for the oxygen evolution reaction (OER) are very crucial for the development and commercialization of sustainable energy conversion technologies. Although spinel catalysts have been widely explored for the electrochemical oxygen evolution reaction (OER), the role of two geometrical sites that influence their activities has not been well established so far. Here, we present more effective cobalt-zinc oxide catalysts for the OER than 'classical' Co3O4. Interestingly, the significantly higher catalytic activity of ZnCo2O4 than that of Co3O4 is somewhat surprising since both crystallize in the spinel-type structure. The reasons for the latter remarkable difference of ZnCo2O4 and Co3O4 could be deduced from structure-activity relationships of the bulk and near-surface of the catalysts using comprehensive electrochemical, microscopic and spectroscopic techniques with a special emphasis on the different roles of the coordination environment of metal ions (octahedral vs. tetrahedral sites) in the spinel lattice. The vital factors influencing the catalytic activity of ZnCo2O4 over Co3O4 could be directly attributed to the higher amount of accessible octahedral Co3+ sites induced by the preferential loss of zinc ions from the surface of the ZnCo2O4 catalyst. The enhanced catalytic activity is accompanied by a larger density of metal vacancies, defective sites and hydroxylation. The results obtained here clearly demonstrate how a surface structural modification and generation of defects of catalysts can enhance their OER performance.
Issue Date: 2016
Date Available: 24-Oct-2017
DDC Class: 540 Chemie und zugeordnete Wissenschaften
530 Physik
Sponsor/Funder: DFG, EXC 314, Unifying Concepts in Catalysis
BMBF, 03IS2071D, Light2Hydrogen
Journal Title: Journal of materials chemistry : A, Materials for energy and sustainability
Publisher: Royal Society of Chemistry
Publisher Place: Cambridge
Volume: 4
Issue: 25
Publisher DOI: 10.1039/c6ta03644a
Page Start: 10014
Page End: 10022
EISSN: 2050-7496
ISSN: 2050-7488
Notes: Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.
Appears in Collections:FG Metallorganische Chemie und Anorganische Materialien » Publications
FG Technische Chemie » Publications

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