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Validation of binuclear descriptor for mixed transition metal oxide supported electrocatalytic water oxidation

Paper ID Volume ID Publish Year Pages File Format Full-Text
55003 47036 2013 6 PDF Available
Title
Validation of binuclear descriptor for mixed transition metal oxide supported electrocatalytic water oxidation
Abstract

The energy profiles of the di-hydroxo – di-oxo – peroxo pathway are discussed for a set of 3d transition metal oxides comprising V(III–V), Cr(III–V), Mn(II–IV, Mn(III–V), Fe(II–IV), Co(II–IV) and Ni(II–IV) using density functional theory (DFT). Two classes of oxides were identified. The first class, comprising V(III–V), Cr(III–V) and Fe(II–IV), displays exothermicity for the oxidation of di-hydroxo to di-oxo versus the tyrosine/tyrosyl-radical (TyrOH/TyrO) couple and endothermicity for the subsequent OO bond formation ([−/+] class), while the second class, comprising Mn(III–V), Co(II–IV) and Ni(II–IV), shows endothermicity with respect to the oxidation step and exothermicity for the OO bond formation ([+/−] class). The energetics of the endothermicity (exothermicity) for the oxidation step is reflected in the exothermicity (endothermicity) of the subsequent OO bond formation step. Mn(II–IV) is not part of any of the two classes. Instead it shows zero exothermicity with respect to TyrOH/TyrO for the oxidation step and a small endothermicity for the OO bond formation step. Despite the promising energy profile Mn(II–IV) is argued to be inactive due to a large activation barrier. A set of improved hetero-nuclear candidate catalysts is predicted by mixing [−/+] with [+/−] transition metal oxides. A simple and efficient method to estimate the energy profile of mixed transition metal oxides from the homo-nuclear systems is demonstrated. The validity of this procedure is checked and agreement with the explicitly calculated values is found. All considered heteronuclear candidate catalysts display enhanced performance compared to the pure homonuclear systems.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (109 K)Download as PowerPoint slideHighlights► A binuclear mechanism for water oxidation is evaluated for transition metal oxides. ► Homonuclear transition metal oxides are classified. ► Improved electrocatalysis is obtained in suitable hetero-binuclear systems. ► Rationale for improved electrocatalytic performance in selectively mixed metal oxides is arrived at.

Keywords
Water oxidation; Mechanism; electrocatalysis; Transition metal oxides; Mixed transition metal oxides; Density functional theory
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Validation of binuclear descriptor for mixed transition metal oxide supported electrocatalytic water oxidation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Catalysis Today - Volume 202, 15 March 2013, Pages 114–119
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us