Overcoming the Activity-Stability Trade-Off in Electrocatalysts via Unconventional Two-Step Structural Reconstructions of Amorphous Oxides

with stable operation for 600 h in anion-exchange membrane water electrolyzers. Using in situ spectroscopic techniques, we establish dynamic correlations among Co ion oxidation states, phase structure, and lattice oxygen activation during reconstruction. Notably, we provide the first experimental evidence of a potential-dependent mechanistic transition governing both the activity and the stability of the catalyst. These findings deepen our understanding of structure-performance relationships in electrocatalysts and highlight the pivotal role of the chemical state evolution in catalytic processes.