Bubble-Induced Current Heterogeneity and Spatially Nonuniform Degradation of OER Electrodes in PEM Water Electrolysis

Abstract Understanding bubble-related phenomena during the oxygen evolution reaction (OER) is essential for devising strategies that ensure stable operation in proton exchange membrane water electrolysis, as oxygen bubbles play a critical role in accelerating the degradation of catalytic performance. Specifically, elevated local current densities induced by bubble accumulation at the electrode surface are known to accelerate catalyst over-oxidation and dissolution, leading to irreversible degradation; however, there has been no direct experimental analysis elucidating the relationship between local activity, durability, and bubble shielding. In this study, spatiotemporally resolved scanning electrochemical microscopy (SECM) was employed to elucidate the impact of bubble shielding on the local activity and durability of OER electrodes; (a) SECM analysis revealed that local current density…