Comparison of amorphous iridium water-oxidation electrocatalysts prepared from soluble precursors

dc.contributor.author	Blakemore, James D.
dc.contributor.author	Schley, Nathan D.
dc.contributor.author	Kushner-Lenhoff, Maxwell N.
dc.contributor.author	Winter, Andrew M.
dc.contributor.author	D'Souza, Francis
dc.contributor.author	Crabtree, Robert H.
dc.contributor.author	Brudvig, Gary W.
dc.date.accessioned	2012-09-09T02:09:46Z
dc.date.available	2012-09-09T02:09:46Z
dc.date.issued	2012-07-16
dc.identifier.citation	James D. Blakemore, Nathan D. Schley, Maxwell N. Kushner-Lenhoff, Andrew M. Winter, Francis D’Souza, Robert H. Crabtree, and Gary W. Brudvig. 2012. Comparison of Amorphous Iridium Water-Oxidation Electrocatalysts Prepared from Soluble Precursors. Inorganic Chemistry, v.51 (14), 7749-7763	en_US
dc.identifier.issn	0020-1669
dc.identifier.uri	http://dx.doi.org/10.1021/ic300764f
dc.identifier.uri	http://hdl.handle.net/10057/5267
dc.description	Click on the DOI link below to access the article (may not be free).	en_US
dc.description.abstract	Electrodeposition of iridium oxide layers from soluble precursors provides a route to active thin-layer electrocatalysts for use on water-oxidizing anodes. Certain organometallic half-sandwich aqua complexes of iridium form stable and highly active oxide films upon electrochemical oxidation in aqueous solution. The catalyst films appear as blue layers on the anode when sufficiently thick, and most closely resemble hydrous iridium(III,IV) oxide by voltammetry. The deposition rate and cyclic voltammetric response of the electrodeposited material depend on whether the precursor complex contains a pentamethylcyclopentadieneyl (Cp*) or cyclopentadienyl ligand (Cp), and do not match, in either case, iridium oxide anodes prepared from non-organometallic precursors. Here, we survey our organometallic precursors, iridium hydroxide, and pre-formed iridium oxide nanoparticles. From electrochemical quartz crystal nanobalance (EQCN) studies, we find differences in the rate of electrodeposition of catalyst layers from the two half-sandwich precursors; however, the resulting layers operate as water-oxidizing anodes with indistinguishable overpotentials and HID isotope effects. Furthermore, using the mass data collected by EQCN and not otherwise available, we show that the electrodeposited materials are excellent catalysts for the water-oxidation reaction, showing maximum turnover frequencies greater than 0.5 mol O-2 (mol iridium)(-1) s(-1) and quantitative conversion of current to product dioxygen. Importantly, these anodes maintain their high activity and robustness at very low iridium loadings. Our organometallic precursors contrast with pre-formed iridium oxide nanoparticles, which form an unstable electrodeposited material that is not stably adherent to the anode surface at even moderately oxidizing potentials.	en_US
dc.language.iso	en_US	en_US
dc.publisher	American Chemical Society	en_US
dc.relation.ispartofseries	Inorganic Chemistry; v.51 no.14
dc.subject	Oxide Thin-Films	en_US
dc.subject	Oxygen evolution	en_US
dc.subject	Cp-Asterisk	en_US
dc.subject	Artificial photosynthesis	en_US
dc.subject	Alkaline-Solutions	en_US
dc.subject	Photosystem-Ii	en_US
dc.subject	Visible-Light	en_US
dc.subject	Catalyst	en_US
dc.subject	Complexes	en_US
dc.subject	Electrode	en_US
dc.title	Comparison of amorphous iridium water-oxidation electrocatalysts prepared from soluble precursors	en_US
dc.type	Article	en_US
dc.description.version	Peer reviewed
dc.rights.holder	Copyright © 2012 American Chemical Society