Surface-Fe enriched trimetallic (oxy)hydroxide engineered by S-incorporation and ligand anchoring toward efficient water oxidation

Surface Fe with low-coordination plays a decisive role in the performance of OER catalysts in basic media, however, it is still a huge challenge to construct a Fe-enriched surface. Herein, a novel S-incorporation and ligand anchoring strategy is reported for in-situ synthesis of surface-Fe enriched OER catalysts. During the OER test, the co-etching of S elements and ligands enables the formation of surface-Fe enriched trimetallic (oxy)hydroxide OER catalysts. Benefiting from the high catalytic activity of Fe enriched species on surface, the electrode delivers an ultralow overpotential of 234 mV to reach the current density of 10 mA cm⁻² and a superior stability over 50 h. This efficient S-incorporation and ligand anchoring strategy offers a new perspective for in-situ construction of advanced earth-abundant OER catalysts.