High Throughput Detection of Onset Potentials of HER Electrodes by an Optical Polarization Imaging Method

Abstract Efficient hydrogen production through water electrolysis relies on catalytic electrodes with low onset potentials and uniform activity. This study presents an optical polarization imaging technique for real‐time, in situ mapping of the activity distribution on catalytic electrode surfaces during the hydrogen evolution reaction (HER) in water electrolysis. By monitoring changes in the degree of polarization (DoP) of the reflected light during bubble formation on the electrode surface, this technique quantitatively analyzes the hydrogen evolution activity. The results demonstrate that our imaging approach provides direct visualization of surface activity heterogeneity, offering critical insights into structure‐performance relationships. Coupled with high‐throughput screening, electrodeposition time is systematically correlated with electrode efficacy, significantly enhancing the efficiency of the screening process. By bridging the gap between localized catalytic behavior and macroscopic durability challenges, this work establishes a framework for rational electrode design, advancing scalable green hydrogen technologies.