Iridium-free high-entropy ruthenium-based oxides with activated lattice oxygen towards high efficient and durable acidic water oxidation

Abstract

Ruthenium-based oxides are promising high-activity acidic OER catalysts to replace IrO₂ but suffer from poor stability. Here, we report an Ir-free high-entropy (RuCrMnFeNi)O₂ electrocatalyst with exceptional activity (212 mV@10 mA cm⁻²) and stability (100 h) in 0.5 M H₂SO₄. In PEM electrolyzers, it operates stably for 300 h at 200 mA cm⁻². ¹⁸O labeling confirms a lattice-oxygen-mediated mechanism.