Dynamic tuning of acidic oxygen evolution reaction pathways in Ru catalysts via Cu-induced surface restructuring

Achieving both high activity and long-term stability for the oxygen evolution reaction (OER) in acidic media remains a critical challenge for proton exchange membrane water electrolyzers (PEMWEs). In this study, we proposed a Cu-incorporated ruthenium (Ru) catalyst (CuRu-250) that exhibited superior performance via dynamic surface modulation during operation. Rather than serving solely as a static dopant, Cu actively influenced the catalyst surface by undergoing partial dissolution and inducing surface restructuring. This dynamic behavior enabled pathway tuning from the adsorbate evolution mechanism to the oxide path mechanism, enhancing the intermediate turnover and suppressing the overoxidation of Ru. Consequently, CuRu-250 demonstrated markedly improved durability and competitive activity compared to undoped Ru and commercial RuO 2 . Single-cell PEMWE tests validated its catalytic performance under realistic conditions. These findings highlight the role of active dopant behavior in tuning acidic OER pathways and improving electrochemical resilience, thus offering a practical strategy for advanced catalyst design.