Enhanced Hydrogen Spillover and Electronic Coupling in Pt‐CeZrO 4 Enables Efficient and Durable Proton Exchange Membrane Water Electrolysis

ABSTRACT Reducing platinum (Pt) loading in proton exchange membrane water electrolysis (PEMWE) is essential for its large‐scale deployment in green hydrogen production. However, the hydrogen evolution reaction (HER) activity of conventional Pt‐based catalysts is fundamentally limited by the volcano relationship, which restricts further performance improvement and the large‐scale application of PEMWE. In addition, commercial carbon‐supported Pt (Pt/C) catalysts are prone to Pt dissolution and detachment under harsh operating conditions. Herein, we address this issue by constructing a Pt‐CeZrO 4 (Pt‐CZO) cluster‐cluster heterostructure with strong interactions. Through comprehensive in situ spectroscopic analysis and theoretical simulations, we demonstrate that during acidic HER, hydrogen atoms adsorb on the Pt surface and rapidly migrate to the Pt─O─Ce interface sites for coupling and desorption. The resulting short‐path hydrogen transfer pathway and strong electronic coupling between Pt and CZO clusters endow the catalyst with exceptional activity and durability in membrane electrode assemblies, achieving a cell voltage of 1.60 V at 1 A cm −2 and a minimal degradation rate of 19.7 µV h −1 over 1000 h with an ultra‐low cathodic loading of 0.1 mg Pt cm −2 , holding substantial promise for use as high‐performance cathode catalysts in PEMWE.