Oxidation-resistant AgRuIr alloy nanocages for efficient and enduring oxygen evolution in proton exchange membrane electrolysis

Abstract The global transition to a hydrogen economy relies on efficient and durable catalysts for the oxygen evolution reaction within proton exchange membrane water electrolysis. Conventional metal oxide catalysts, particularly RuO 2 , suffer from overoxidation and corrosion under acidic and high-potential conditions, limiting operational lifetime. Here we report a metallic catalyst composed of metastable AgRuIr alloy nanocages that challenge the prevailing view that metallic materials are unsuitable for this reaction. Mechanistically, the filled d orbitals of Ag reduce the oxophilicity of the alloy, weakening oxygen adsorption and preventing oxygen incorporation into the metal lattice. As a result, the nanocages exhibit higher activity than Ru/Ir oxides while maintaining a metallic state at high potentials, thereby fundamentally suppressing overoxidation. In a water electrolysis cell, the catalyst delivers 1 A cm −2 at a cell voltage of 1.73 V and operates stably for 1500 hours with negligible voltage increase (0.93 μV h −1 ) and minimal metal dissolution (0.5–0.7% kh −1 ). These results redefine the potential of metallic catalysts for oxygen evolution in proton exchange membrane water electrolysis systems toward large-scale hydrogen production.