Issue 8, 2024

Enhanced electrochemical dissolution of iridium oxide in acidic electrolytes through presence of metal ions: shortened lifetime and hope for recovery

Abstract

Nanoparticulate Ir-oxides are frequently used as highly active and robust anode electrocatalysts for acidic water electrolyzers. While their dissolution during the electrolyzer operation is unsought, it could be a green route for recovery of Ir from the spent electrodes. In this study, we explore such a possibility and show that the electrochemical dissolution of Ir-oxides during a potential cycling treatment can be enhanced by introducing transition metal ions (such as Cu2+) in the acidic electrolyte. Dissolution of Ir from a nanoparticulate Ir-oxide containing electrode through potential cycling between 0.0 and 1.65 V in 1 M HCl increases by a factor of ∼3 in the presence of low concentrations (e.g. 10 mM) of Cu2+. Impact of the presence of the metal ions on the Ir-oxide dissolution mechanism is characterized. Cyclic deposition and stripping of the Cu2+ ion on the Ir-oxide may be attributed to the enhanced Ir dissolution, as evidenced by cyclic voltammograms studied in detail for Cu2+. Apart from exploration of the possibility of the electrochemical dissolution-based recovery of Ir from the spent Ir-oxide electrocatalysts, the study highlights the generally negative impacts of the presence of certain metal ions in the feedstock water on the electrocatalyst durability in acidic water electrolysis. Outcomes of this study are highly relevant for the fast-growing acidic water electrolysis industry.

Graphical abstract: Enhanced electrochemical dissolution of iridium oxide in acidic electrolytes through presence of metal ions: shortened lifetime and hope for recovery

Article information

Article type
Paper
Submitted
21 May 2024
Accepted
27 Jun 2024
First published
28 Jun 2024
This article is Open Access
Creative Commons BY license

RSC Sustain., 2024,2, 2225-2238

Enhanced electrochemical dissolution of iridium oxide in acidic electrolytes through presence of metal ions: shortened lifetime and hope for recovery

R. Sharma, P. Morgen, D. Makovec, S. Gyergyek and S. M. Andersen, RSC Sustain., 2024, 2, 2225 DOI: 10.1039/D4SU00257A

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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