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 RuO2, 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.