Regulation of Oxide Pathway Mechanism for Sustainable Acidic Water Oxidation

The advancement of acid-stable oxygen evolution reaction (OER) electrocatalysts is crucial for efficient hydrogen production through proton exchange membrane (PEM) water electrolysis. Unfortunately, the activity of electrocatalysts is constrained by a linear scaling relationship in the adsorbed evolution mechanism, while the lattice-oxygen-mediated mechanism undermines stability. Here, we propose a heterogeneous dual-site oxide pathway mechanism (OPM) that avoids these limitations through direct dioxygen radical coupling. A combination of Lewis acid (Cr) and Ru to form solid solution oxides (CrRu_1-O₂) promotes OH adsorption and shortens the dual-site distance, which facilitates the formation of *O radical and promotes the coupling of dioxygen radical, thereby altering the OER mechanism to a Cr-Ru dual-site OPM. The Cr_0.6Ru_0.4O₂ catalyst demonstrates a lower overpotential than that of RuO₂ and maintains stable operation for over 350 h in a PEM water electrolyzer at 300 mA cm^-2. This mechanism regulation strategy paves the way for an optimal catalytic pathway, essential for large-scale green hydrogen production.