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Microenvironment Matters: Destabilization of Iridium Anode Catalyst by CO Reduction Products
Attila Kormányos1, Mohd Monis Ayyub1, Bence Kutus2
1Department of Physical Chemistry and Materials Science, University of Szeged, Rerrich square 1, Szeged H-6720, Hungary.
Journal of the American Chemical Society
|February 19, 2026
Summary
Iridium anode catalyst stability in CO2 electrolysis is compromised by fuel crossover. Ethanol and acetaldehyde accelerate iridium dissolution by interfering with protective oxide layer formation.
Area of Science:
- Electrochemistry
- Materials Science
- Catalysis
Background:
- Iridium is a key anode electrocatalyst for CO2 and CO electrolysis due to its OER overpotential and stability.
- Recent studies questioned iridium stability, attributing it solely to thermodynamic limitations in alkaline conditions.
Purpose of the Study:
- To investigate the impact of electrolysis products on iridium anode stability.
- To elucidate the mechanism of iridium dissolution during long-term CO2 electrolysis.
Main Methods:
- Ex-situ and in situ inductively coupled plasma mass spectrometry (ICP-MS) were used to study iridium dissolution.
- Electrolysis experiments were conducted across a wide pH range (4-14).
Main Results:
- Liquid CO and CO2 electrolysis products, specifically ethanol and acetaldehyde, significantly decrease iridium stability.
- Ethanol/acetaldehyde oxidation competes with the oxygen evolution reaction (OER).
- This competition prevents the formation of a passivating iridium oxide layer, increasing dissolution rates.
Conclusions:
- Fuel crossover is a critical factor affecting iridium anode stability, beyond thermodynamic considerations.
- Understanding these crossover effects is crucial for designing stable electrocatalysts for CO2 and CO electrolysis.
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