Lithium-directed transformation of amorphous iridium (oxy)hydroxides to produce active water oxidation catalysts

Ruiz Esquius, Jonathan, Morgan, David J. ORCID: https://orcid.org/0000-0002-6571-5731, Algara Siller, Gerardo, Gianolio, Diego, Aramini, Matteo, Lahn, Leopold, Kasian, Olga, Kondrat, Simon A., Schlögl, Robert, Hutchings, Graham J. ORCID: https://orcid.org/0000-0001-8885-1560, Arrigo, Rosa and Freakley, Simon J. 2023. Lithium-directed transformation of amorphous iridium (oxy)hydroxides to produce active water oxidation catalysts. Journal of the American Chemical Society 145 (11) , pp. 6398-6409. 10.1021/jacs.2c13567

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Abstract

The oxygen evolution reaction (OER) is crucial to future energy systems based on water electrolysis. Iridium oxides are promising catalysts due to their resistance to corrosion under acidic and oxidizing conditions. Highly active iridium (oxy)­hydroxides prepared using alkali metal bases transform into low activity rutile IrO2 at elevated temperatures (>350 °C) during catalyst/electrode preparation. Depending on the residual amount of alkali metals, we now show that this transformation can result in either rutile IrO2 or nano-crystalline Li-intercalated IrO x . While the transition to rutile results in poor activity, the Li-intercalated IrO x has comparative activity and improved stability when compared to the highly active amorphous material despite being treated at 500 °C. This highly active nanocrystalline form of lithium iridate could be more resistant to industrial procedures to produce PEM membranes and provide a route to stabilize the high populations of redox active sites of amorphous iridium (oxy)­hydroxides.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Chemistry
Additional Information:	License information from Publisher: LICENSE 1: URL: https://creativecommons.org/licenses/by/4.0/, Start Date: 2023-03-09
Publisher:	American Chemical Society
ISSN:	0002-7863
Date of First Compliant Deposit:	24 March 2023
Date of Acceptance:	23 February 2023
Last Modified:	23 May 2023 23:36
URI:	https://orca.cardiff.ac.uk/id/eprint/157921

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