Short‐Range‐Engineered Nd‐Doped IrO _x Enables Oxide Path Mechanism for High‐Performance PEM Water Electrolysis

ABSTRACT Proton‐exchange‐membrane water electrolysis (PEMWE) demands high‐performance anodes with minimal iridium content, yet conventional Ir‐based catalysts suffer from an inherent activity‐stability trade‐off. We address this challenge by designing neodymium‐doped amorphous IrO x catalysts (Nd‐IrO x ) that enable precise control over short‐range structure to activate the oxide path mechanism (OPM). Incorporating Nd 3+ into an amorphous IrO x matrix dominated by edge‐sharing [IrO 6 ] octahedra optimizes the prerequisites for the OPM: lattice distortion tailors Ir‐Ir distances to enable direct *O‐O* coupling, while electronic modulation stabilizes OH ligands within the local coordination environment, facilitating *O formation. The optimized Nd‐IrO x catalyst delivers an ultralow acidic OER overpotential of 254 mV at 10 mA cm −2 with 520 h of stability. Remarkably, PEMWE employing an ultralow Ir‐loading anode (0.5 mg Ir cm −2 ) achieves a DOE‐relevant current density (4 A cm −2 at 1.9 V) and remarkable 1000‐h stability at 1 A cm −2 . This work pioneers short‐range engineering in Ir‐based oxides, offering fundamental insights for catalyst design and OER pathway control toward efficient hydrogen production.