High current density alkaline water electrolysis enhanced by multi-site cooperative strategy

A cost-effective and robust electrocatalyst that can operate at industrial-scale current densities is critical for producing green hydrogen through water splitting. We present a 2D RuCoFeO_x nanosheet structure, serving as an electrocatalyst for both water splitting and anion-exchange membrane water electrolyzer (AEMWEs) study. The composite material demonstrates outstanding electrochemical performance with acceleration in OER kinetics, enhancement in active surface area, reduced overpotentials, and excellent stability. Based multiple synchrotron radiation techniques and in-situ spectroscopes, we have revealed the electron coupling between Co/Fe and Ru through oxygen-bridge bonding and multi-site cooperative effect. The advanced mapping of resonant Auger spectroscopy (mRAS) effectively differentiates distinct orbital hybridization states, thereby confirming charge transfer between sites. In-situ attenuated total reflection surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS) and indicates that loaded Ru serve as additional adsorption sites, modulating adsorption of *OOH intermediates. In AEMWEs, the RuCoFeO_x showcases high activity, achieving 1 A cm⁻² at 1.76 V, and maintains stability at 1 A cm⁻² beyond 700 h. Our investigation offers an insight into the principles of multisite cooperative catalysis and propels the design of highly efficient electrocatalysts for water splitting.