NdO‐Intensified Dual‐Site Synergy in IrMnO x for Acidic Oxygen Evolution

Abstract The development of low‐iridium (Ir) electrocatalysts for proton exchange membrane water electrolyzers (PEMWEs) remains a significant challenge. In this work, we present an IrNdMnO x catalyst synthesized by incorporating neodymium oxide (NdO x ) into an IrMnO x matrix, forming a triple solid‐solution oxide. The resulting IrNdMnO x catalyst achieves an impressive mass‐specific activity of 769 A g −1 at an ultralow Ir loading of 0.09 mg Ir cm −2 , with overpotential of 331 mV @ 100 mA cm −2 ‐substantially outperforming conventional IrO 2 catalysts (416 mV @100 mA cm −2 ). In a PEMWE cell, the IrNdMnO x anode sustained stable operation at 1 A cm −2 for over 800 h at ∼1.78 V. Differential electrochemical mass spectroscopy measurements and X‐ray absorption spectroscopy analysis indicate that doping with large‐ionic‐radius neodymium (Nd) creates an asymmetric Nd‐O‐Ir‐O‐Mn coordination structure. This unique configuration not only shortens the Ir‐Mn distance to promote the oxygen–oxygen radical coupling mechanism (ORCM) but also finely tunes the electronic structure of Ir sites, reconciling high optimal catalytic activity with robust stability. This work establishes NdO x doping as a strategy to enhance the activity, stability, and cost‐efficiency of Ir‐based catalysts for acidic OER, advancing the development of sustainable hydrogen production.