Engineering the Electronic Configuration of Ir to Develop Efficient and Cost-Effective Electrocatalysts for Proton Exchange Membrane Water Electrolysis

Low-temperature water electrolysis can rapidly produce environmentally sustainable or green hydrogen, and is a prospective means of storing energy from renewable but intermittent power sources, such as wind and solar, in future clean energy infrastructure (1-4). Commercial water electrolysis either use liquid alkaline electrolyte or proton exchange membrane electrolyte (1). The proton exchange membrane water electrolysis (PEMWE) offers more advantages than the alkaline counterpart, such as higher purity of H2, lower resistance losses, more compact design, and what the most important is the compatible with the intermittent of the renewable energy (1-2). The development of high-performance, durable, and low-cost electrocatalysts for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is critical to enabling scalable green hydrogen production through proton exchange membrane water electrolysis (PEMWE). This work highlights three synergistic strategies to address the limitations of iridium-based catalysts. First, a lanthanum- and manganese-doped cobalt spinel nanofiber catalyst (5), derived from a zeolitic imidazolate framework, achieves an OER overpotential of 353 mV at 10 mA cm⁻² in acidic media and demonstrates stable PEMWE performance (2.47 V @ 2 A cm⁻², Nafion 115) for 360 hours, showcasing the viability of earth-abundant alternatives. Second, Ir- and Ru-integrated catalysts on defect-rich La/Li-doped Co₃O₄ nanofibers (LLCF) exhibit exceptional mass activities (26–50× higher than commercial IrO₂/RuO₂) and stability (6), attributed to optimized ligand environments and suppressed metal over-oxidation, as revealed by operando XAS and DFT. Third, a bifunctional core-shell IrPt nano-alloy on La/Ni-doped Co oxide achieves 2 A cm⁻² at 1.72 V with ultralow loadings (0.075 mg cm⁻² for Ir and Pt) and sustains operation for 646 hours (degradation: 5 μV h⁻¹), enabled by charge redistribution, hierarchical porosity, and dual active-site mechanisms. Collectively, these advances underscore the efficacy of doping, nanostructuring, and substrate engineering in tailoring catalytic activity and durability. The integration of advanced synthesis, operando characterization, and computational modeling provides a roadmap for designing next-generation PEMWE catalysts that minimize precious metal reliance while maximizing efficiency and cost-effectiveness, accelerating the transition to sustainable hydrogen economies. Keywords: Oxygen evolution reaction, PEM water electrolysis, Earth-abundant catalysts, Core-shell structures, Operando characterization. Acknowledgments: This work was supported by Overseas Outstanding Youth Fund project, shanghai Jiao Tong university, Shanghai, China; Shanghai Pujiang talent Plan, Shanghai, China; State Key Laboratory of Metal Matrix Composites, shanghai Jiao Tong university, Shanghai, China. Reference: 1. K. Ayers et al., Annu. Rev. Chem. Biomol. Eng. 10, 219–239 (2019). 2. M. Carmo, D. L. Fritz, J. Mergel, D. Stolten, Int. J. Hydrogen Energy 38, 4901–4934 (2013). 3. M. T. M. Koper, J. Electroanal. Chem. 660, 254–260 (2011). 4. R. D. L. Smith et al., Science 340, 60–63 (2013). 5. Chong et al., Science 380, 609–616 (2023). 6. Chong et al., Adv. Energy Mater. 2023, 2302306.