Dual Rare‐Earth‐Induced Synergistic Lattice Strain and Electronic Reconfiguration Modulate Ru─O Covalent Bonds for Robust Acidic Oxygen Evolution

ABSTRACT Ruthenium oxide (RuO 2 ) is a promising alternative to Ir‐based catalysts for the acidic oxygen evolution reaction (OER) owing to its high intrinsic activity, yet its practical application is hindered by rapid degradation under strongly oxidative acidic conditions. Herein, we report a dual rare‐earth co‐doping strategy to regulate Ru─O bonding through the synergistic coupling of strain and electronic effects. Incorporation of lanthanum (La) and neodymium (Nd) into the rutile RuO 2 lattice induces a 2.41% lattice expansion, resulting in elongated Ru─O bonds and weakened Ru─O covalency. These structural modifications suppress lattice oxygen activation and stabilize the oxide framework. Meanwhile, rare‐earth‐induced electronic modulation lowers the energy barrier for the *O to *OOH transition, steering OER toward a more stable adsorbate evolution mechanism (AEM) pathway. Consequently, LaNd‐RuO 2 achieves an overpotential of only 185 mV at 10 mA cm −2 in 0.5 M H 2 SO 4 and sustains stable operation for over 1200 h, significantly outperforming singly doped counterparts. A proton exchange membrane water electrolyzer employing LaNd‐RuO 2 as the anode catalyst requires only 1.81 V to reach 3 A cm −2 . This work offers an effective strategy for simultaneously enhancing the activity and durability of Ru‐based acidic OER catalysts.