Regulation\nof Oxide Pathway Mechanism for Sustainable\nAcidic Water Oxidation

The advancement of acid-stable oxygen\nevolution reaction (OER)\nelectrocatalysts is crucial for efficient hydrogen production through\nproton exchange membrane (PEM) water electrolysis. Unfortunately,\nthe activity of electrocatalysts is constrained by a linear scaling\nrelationship in the adsorbed evolution mechanism, while the lattice-oxygen-mediated\nmechanism undermines stability. Here, we propose a heterogeneous dual-site\noxide pathway mechanism (OPM) that avoids these limitations through\ndirect dioxygen radical coupling. A combination of Lewis acid (Cr)\nand Ru to form solid solution oxides (Cr<sub><i>x</i></sub>Ru<sub>1–<i>x</i></sub>O<sub>2</sub>) promotes OH\nadsorption and shortens the dual-site distance, which facilitates\nthe formation of *O radical and promotes the coupling of dioxygen\nradical, thereby altering the OER mechanism to a Cr–Ru dual-site\nOPM. The Cr<sub>0.6</sub>Ru<sub>0.4</sub>O<sub>2</sub> catalyst demonstrates\na lower overpotential than that of RuO<sub>2</sub> and maintains stable\noperation for over 350 h in a PEM water electrolyzer at 300 mA cm<sup>–2</sup>. This mechanism regulation strategy paves the way\nfor an optimal catalytic pathway, essential for large-scale green\nhydrogen production.