Unlocking Superior Stability in High-Salinity Oxygen Evolution Reaction: A Ru Stabilized NiFeOOH/Ni Anode with over 2000 h Durability

Saline water electrolysis presents a promising pathway for green hydrogen production by leveraging abundant saline water resources instead of scarce freshwater. However, the presence of highly corrosive chloride ions (Cl^-) severely undermines anode durability. This instability arises from two main issues: (i) penetration of Cl^- through catalyst layers to the underlying substrate and (ii) degradation of active catalytic sites due to Cl^- attack. To tackle both issues simultaneously, we introduce ruthenium (Ru) ions as a dual-function stabilizing agent in NiFe-based anodes. Our results show that Ru incorporation promotes the formation of a protective surface layer enriched with Ru atoms, along with a denser NiFeOOH catalyst structure, which collectively inhibit Cl^- infiltration. Moreover, atomically dispersed ruthenium (Ru_SA) within the NiFeOOH matrix effectively mitigates Cl^--induced corrosion of active sites. Thanks to this dual stabilization effect, the resulting Ru_SA-NiFeOOH/Ni anode exhibits exceptional operational stability-over 2000 h at an industrial current density of 0.5 A cm^-2 in a chloride-enriched alkaline medium (1 M KOH + 2 M NaCl)-setting a new benchmark for performance under such aggressive conditions. This study establishes a robust dual stabilization strategy that significantly enhances anode stability in saline water electrolysis.