Electron Transfer Mediator Effects in the Oxidative Activation of a Ruthenium Dicarboxylate Water Oxidation Catalyst
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
>The mechanism of electrocatalytic water oxidation by the water oxidation catalyst, ruthenium 2,2'-bipyridine-6,6'-dicarboxylate (bda) bis-isoquinoline (isoq), [Ru(bda)(isoq)2], 1, at metal oxide electrodes has been investigated. At indium-doped tin oxide (ITO), diminished catalytic currents and increased overpotentials are observed compared to glassy carbon (GC). At pH 7.2 in 0.5 M NaClO4, catalytic activity is enhanced by the addition of [Ru(bpy)3]2+ (bpy = bipyridine) as a redox mediator. Enhanced catalytic rates are also observed at ITO electrodes derivatized with the surface-bound phosphonic acid derivative [Ru(4,4'-(PO3H2)2bpy)(bpy)2]2+, RuP2+. Controlled potential electrolysis with measurement of O2 at ITO with and without surface-bound RuP2+ confirm that water oxidation catalysis occurs. Remarkable rate enhancements are observed with added acetate and phosphate, consistent with an important mechanistic role for atom-proton transfer (APT) in the rate-limiting step as described previously at GC electrodes.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Alliance for Molecular PhotoElectrode Design for Solar Fuels (AMPED); University of North Carolina, Chapel Hill, NC (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0001011
- OSTI ID:
- 1194819
- Alternate ID(s):
- OSTI ID: 1385928
- Journal Information:
- ACS Catalysis, Journal Name: ACS Catalysis Vol. 5 Journal Issue: 7; ISSN 2155-5435
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
water oxidation
electrocatalysis
electron transfer
polypyridyl ruthenium complexes
water splitting
catalysis (homogeneous)
catalysis (heterogeneous)
solar (photovoltaic)
solar (fuels)
photosynthesis (natural and artificial)
hydrogen and fuel cells
electrodes - solar
charge transport
materials and chemistry by design
synthesis (novel materials)
synthesis (self-assembly)