Lanthanum‐Induced Interfacial Engineering of IrO x /TiO 2 for Highly Efficient Oxygen Evolution in PEM Water Electrolysis

ABSTRACT High Ir cost and inefficient catalyst utilization remain critical challenges for scalable proton exchange membrane water electrolysis (PEMWE), particularly at the anode where acidic oxygen evolution requires large amounts of Ir‐based catalysts. Herein, we report a La‐enabled interfacial engineering strategy that constructs a uniform La‐modulated IrO x layer on TiO 2 for low‐Ir PEMWE anodes. La incorporation induces IrO 6 octahedral distortion, enriches surface hydroxyl species, suppresses oxygen vacancy formation, and increases near‐Fermi‐level electronic states, collectively modulating Ir 5 d– O 2 p hybridization and accelerating deprotonation kinetics during acidic oxygen evolution reaction (OER). As a result, the optimized catalyst delivers a low overpotential of 270 mV at 10 mA cm − 2 and a suppressed degradation rate of 0.12 mV h − 1 in acidic half‐cell tests. When implemented in a membrane electrode assembly, the catalyst achieves 3.71 A cm − 2 at 1.8 V under a low‐platinum group metals (PGM) configuration, exceeding the DOE 2026 target. This work demonstrates that La‐driven interfacial engineering effectively translates intrinsic OER activity into high‐current‐density PEMWE performance, offering a practical route toward high‐performance low‐Ir anode catalysts.