OER Catalyst Durability Tests Using the Rotating Disk Electrode Technique: The Reason Why This Leads to Erroneous Conclusions

This study reveals the physical origin of the rapid performance decay when measuring the activity and durability of oxygen evolution reaction (OER) catalysts using the rotating disk electrode (RDE) technique or other half-cell test configurations with liquid electrolyte. By subjecting the electrochemical cell or the electrolyte to ultrasonication while conducting a typical RDE-based measurement of the OER performance of a polycrystalline iridium-disk electrode, we demonstrate that it is the accumulation of microscopic oxygen bubbles that is responsible for the rapid OER catalyst performance decay observed during RDE experiments.