Circumventing the Linear Scaling Limitation in Oxygen Evolution by Metal‐Site Proton‐Acceptor‐Assisted Deprotonation

ABSTRACT Oxygen evolution reaction electrocatalysts following the adsorbate evolution mechanism (AEM) exhibit exceptional structural stability, but the activity is inherently constrained by the linear scaling relationship associated with single‐metal sites. Here, we propose a metal‐site proton‐acceptor‐assisted deprotonation AEM (MP‐AEM) by incorporating Pd into RuO 2 as secondary metal‐site proton acceptors to activate a novel proton‐transfer pathway. Theoretical calculations and operando characterizations confirm that Pd‐RuO 2 generates new intermediates, reducing the rate‐determining energy barrier by 0.41 eV. Moreover, Pd proton acceptor lowers the O─H bond dissociation barrier and optimizes the hydrogen‐bond network, thereby accelerating the deprotonation kinetics. Furthermore, reduced Ru valence and weakened Ru─O covalency inhibit Ru oxidative dissolution and the lattice‐oxygen‐mediated mechanism. The Pd‐RuO 2 applied in proton exchange membrane water electrolyzers (PEMWEs) requires only 1.55 V @ 1 A cm −2 and shows 15‐fold higher stability than pure RuO 2 . This work establishes an innovative pathway and insight for designing highly efficient PEMWEs catalysts.