Theory‐Guided Design of Ru–NiFe Cathode Catalysts for Anion Exchange Membrane Water Electrolysis at Large Electrode Scale

A significant gap persists between advanced catalyst synthesis in laboratories and the industrial requirements for water electrolysis. The key challenge lies in simultaneously achieving electrode scalability, high catalytic activity, and long-term stability. Through theoretical simulation screening, we synthesized a free-standing cathode catalyst composed of Ru clusters anchored on a Ni_xFe_yOOH substrate via Ru─O─Ni/Fe bridges. Advanced characterizations and theoretical calculations reveal that the Ru-NiFe catalyst achieves efficient catalytic activity due to Ru─O─Ni/Fe bridges, fine-tuning the electronic structure and enhancing catalytic energetics, while Ru cluster introduction increases the number of active sites and modulates hydrogen intermediate adsorption/desorption strength. The as-prepared Ru-NiFe electrocatalyst for the hydrogen evolution reaction delivers ultralow overpotentials of 5 mV at 10 mA cm^- ² and maintains stable operation at 500 mA cm^- ² for over 1000 h. A large-scale (19 × 19 cm²) anion-exchange-membrane water electrolyzer (AEM-WE) based on Ru-NiFe shows a low cell voltage of 2.98 V at 10 A and stable operation for 2800 h. This study provides valuable insights into designing large-area electrodes with high activity, long-term stability, and scalable production for industrial AEM-WE applications.