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Spectroelectrochemical investigation of electrocatalytic water oxidation by a mononuclear ruthenium complex in a homogeneous solution

Paper ID Volume ID Publish Year Pages File Format Full-Text
26473 43954 2015 5 PDF Available
Title
Spectroelectrochemical investigation of electrocatalytic water oxidation by a mononuclear ruthenium complex in a homogeneous solution
Abstract

•Electrocatalytic water oxidation was studied by Potential-step chronocoulospectrometry.•[Ru(EtOtpy)(bpy)OH2]2+ can work for electrocatalytic water oxidation under weakly acidic conditions.•The rate-determining step for the electrocatalysis is oxidation of RuIVO to RuVO species.

Electrochemical water oxidation by [Ru(EtOtpy)(bpy)OH2]2+ (1) (EtOtpy = 4′-ethoxy-2,2′:6#6°6#′-terpyridine, bpy = 2,2′-bipydidine) was investigated in a homogeneous solution under weakly acidic conditions (pH 5.3). The cyclic voltammogram of a 1 aqueous solution showed that successive proton-coupled electron transfer reactions of RuIIOH2 / RuIIIOH and RuIIIOH/RuIVO redox pairs and high anodic current above 1.1 V vs SCE. Electrocatalytic water oxidation was corroborated by the bulk electrolysis at 1.5 V; the significant amount of O2 was evolved compared with the blank during the electrolysis. Potential-step chronocoulospectrometry (PSCCS) from 0.0 V to 1.52 V vs SCE was conducted to observe the change of 1 in solution during the electrocatalysis. The in situ UV visible spectral change showed oxidation of 1 (RuIIOH2) to RuIIIOH and to further oxidation of RuIIIOH to RuIVO, and that the RuIVO species mainly exists in a steady state after 200 s in the electrocatalysis. The in situ UV–vis spectral change in a reverse potential step from 1.52 V to 0.22 V vs SCE exhibited that RuIIOH2 completely recovers by two electron re-reduction process from the steady state in the electrocatalysis. The observation of RuIVO in a steady state suggests that a rate determining step in the catalytic cycle is oxidation of RuIVO to RuVO rather than the OO bonding formation by nucleophilic attack of water to RuVO in the electrocatalysis in a homogeneous solution.

Keywords
Water oxidation catalyst; Mononuclear rutheniumu complex; Spectroelectrochemical method; Aritificial photosyntheis
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Spectroelectrochemical investigation of electrocatalytic water oxidation by a mononuclear ruthenium complex in a homogeneous solution
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology A: Chemistry - Volume 313, 1 December 2015, Pages 126–130
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
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
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Any Questions? feel free to contact us