Understanding and Tackling Dynamic Electrocatalyst Degradation under Fluctuating Water-Splitting Conditions

Directly coupling electrolyzers with renewable electricity is critical for widespread, cost-effective green fuel production, yet the inherent power variability accelerates electrolyzer degradation. Proton exchange membrane water electrolysis (PEMWE), a scalable hydrogen-production technology, is further limited by the scarcity of iridium as the benchmark oxygen evolution reaction (OER) catalyst. While alternatives including ruthenium-based and even noble-metal-free oxides (e.g., Science 2025, 387,48-55, Science 2024, 384, 1373) have emerged, their stability remains inadequate even under steady conditions (e.g., >60°C, > 1A cm−2). Intermittent operation further challenges these representative OER catalysts, and the underlying degradation mechanisms remain unclear.This project will first elucidate dynamic electrocatalyst degradation under fluctuating water-oxidation conditions by combining multiscale, millisecond-resolution high-speed operando characterizations with tailored power profiles (hold, square-wave, and triangle-wave cycles at varying potentials/frequencies). Using model oxide catalysts spanning both iridium-based and iridium-free oxides (IrO₂, RuO₂, MnO₂, Co₃O₄), we aim to uncover how intermittent operation accelerates degradation through pathways such as active-site dissolution, configurational reconstruction (e.g., by frequent redox cycling), and interfacial deterioration. Temporally resolved operando techniques (down to 100 ms) across catalyst, interface, and cell levels will clarify degradation origins and enable reliable extrapolation for predicting long-term stability. This integrated approach will establish how cycling conditions govern degradation kinetics and distribution and also address electrode-scale heterogeneity, where localized variations in current, temperature, and mechanical stress may lead to spatially non-uniform performance loss.We will then employ a \"disorder tailoring\" strategy to mitigate dynamic degradation through controlled synthesis and heteroatom doping. This approach enables bidirectional tuning of catalyst disorder (degree, range, distribution)—introducing beneficial disorder or reducing excessive randomness—to optimize structural and electronic properties (e.g., local flexibility). Such modifications optimize interactions with reaction intermediates and electrolytes, improving OER performance. First-principle calculations will be conducted to model the disordered structure (e.g., via a simulated melt-quench method) and supplement operando characterizations to clarify the modulation mechanisms. Finally, optimized catalysts and membrane electrode assemblies will be validated in PEM electrolyzers under simulated fluctuating conditions (following national standards) and actual solar cell coupling. Our target is a stable hydrogen gas output with <3% degradation over 100 days under fluctuating conditions, setting a benchmark performance.By pioneering the investigation of electrocatalysts under fluctuating power conditions, this project will advance the practical design of catalysts and the development of clean energy technologies.