Structure Disorder-Induced Dynamic Oxophilic Surface Boosting O* Radical Dimerization for Superior Acid Oxygen Evolution

Globally, the proton exchange membrane water electrolyzers (PEMWEs) already account for approximately 30% of the hydrogen market and are undergoing rapid expansion. However, the commercially used iridium-based anodic oxygen evolution reaction (OER) catalysts in PEMWEs still suffer from notably poor reactivity. At present, the oxide pathway mechanism (OPM) is an important route to achieve both high activity and durability in OER. Nevertheless, the performance of conventional Ir-based crystalline OER catalysts following the OPM pathway remains far below their theoretical limit, which is significantly hindered by two intrinsic limitations. First, their rigid lattice structures prevent the shortening of metal-metal distances, which is essential to facilitate the rate-determining O * ─O * dimerization. Second, the repulsion between O * adsorbates during OER inevitably weakens the metal = O * bond and undermines the overall oxygen evolution efficiency. Herein, we report that an amorphous IrMO x catalyst elegantly overcomes the limitations of the OPM pathway by virtue of its dynamic surface structure and strong oxophilicity of M.  The dynamic surface structure promotes O * ─O * coupling, while the oxophilic nature of M compensates for the inherent weakening of the metal = O * bond during OER. Because of that, the catalyst exhibits outstanding OER performance, along with excellent catalytic durability over 1200 h’ PEM testing.