Synergistic Catalysis of Pt‐Based High‐Entropy Clusters Coupled with Super‐Hydrophilic CeO ₂ Enables Efficient Anion Exchange Membrane Water Electrolysis

Simultaneously enhancing the intrinsic activity and accelerating H₂O dissociation kinetics is crucial for developing advanced low-Pt electrocatalysts for the alkaline hydrogen evolution reaction (HER). Herein, a low-noble-metal Pt-based high-entropy alloy clusters coupled with super-hydrophilic CeO₂ on porous carbon support (Pt-HEA-cluster/CeO₂/C) is developed. The optimized Pt-HEA-cluster/CeO₂/C catalyst exhibits the faster Volmer-Tafel mechanism with an exceptionally low overpotential of 12.3 mV at -10 mA cm^-2 in 1.0 m KOH, surpassing the benchmark commercial Pt/C (32.2 mV). When integrated into an anion exchange membrane water electrolysis, the system achieves low cell voltages of 1.74 V at 1 A cm^-2, and can maintain its performance for at least 500 h at an industrial-level current density. Operando spectroscopy and density functional theory calculations reveal that H₂O preferentially adsorbs on Ce site of CeO₂, while the interfacial Pt sites in contact with Ce can simultaneously act as efficient active sites for H₂O dissociation, thus significantly enhancing the sluggish Volmer kinetics via Ce-Pt dual-site synergy. Concurrently, the electronic structure of surface Pt sites is synergistically regulated through the metal bonds in the HEA and interfacial Pt─O─Ce linkage, thus effectively optimizing its hydrogen adsorption free energy. This work establishes a new paradigm in synergistic catalysis between Pt-HEA-clusters and CeO₂ for efficient alkaline HER.