Short-Range-Engineered Nd-Doped IrOx Enables Oxide Path Mechanism for High-Performance PEM Water Electrolysis

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.