High-stability K0.25Ir0.5Ru0.5O2 Anode Catalyst for Proton Exchange Membrane Water Electrolysis under Industrial Operation Conditions

While reducing Ir with Ru has emerged as a prominent research trend in anode catalysts for cost reduction and activity enhancement, achieving long-term durability in proton-exchange membrane (PEM) water electrolyzer (PEMWE) technology remains a significant challenge. Here, we develop a 1D K0.25Ir0.5Ru0.5O2 nanowire as anode catalyst for oxygen evolution reaction (OER). Comprehensive characterization confirms that K0.25Ir0.5Ru0.5O2 possesses a novel crystal structure in which K⁺ intercalated between Ir and Ru atomic columns provides sufficient stabilization in neighboring bimetallic sites. Synergy between bimetallic atomic columns in this Ru-rich catalyst reduces the Gibbs free energy and weakens O* adsorption in the Ir-like AEM pathway. Therefore, the K0.25Ir0.5Ru0.5O2 catalyst exhibits exceptional OER activity, achieving an ultralow overpotential of 184 mV at 10 mA cmgeo-2 in a three-electrode system and a low cell voltage of 1.775 V at 3.0 A cmgeo-2 in a PEMWE system. The long-term stability of the Ru-rich structure in this potassium-metal oxides is further demonstrated under both steady-state operation (>6500 h) and simulated dynamic power inputs (>2800 h). By synergistically merging Ru-like activity with Ir-like durability, K0.25Ir0.5Ru0.5O2 holds great potential to bridge the gap between fundamental research and industrial PEMWE application for Ru-based catalysts.