Iron Molybdenum Sulfide‐Supported Ultrafine Ru Nanoclusters for Robust Sulfion Degradation‐Assisted Hydrogen Production

Abstract Electrocatalytic hydrogen evolution and (S 2− ) recycling present promising strategies for cost‐effective hydrogen production and simultaneous removal of environmental pollutants. However, the advancement of this technology is hindered by the limited availability of affordable, efficient, and stable catalysts. Herein, the study synthesizes ultrafine ruthenium (Ru) nanoclusters on a substrate of iron molybdenum sulfide (FeMo‐S) nanosheets, creating a new heterointerface catalyst (FeMo‐S/Ru) for the hydrogen evolution reaction (HER) and sulfion oxidation reaction (SOR). Experimental and theoretical calculations suggest that strong electron interactions between Ru nanoclusters and FeMo‐S substrate, optimizing *H adsorption and promoting HER activity on one side while facilitating the production and adsorption of sulfur intermediates on the other side, effectively catalyzing SOR. Additionally, the assembled electrocatalytic coupling system with FeMo‐S/Ru displays an ultralow cell voltage of 0.57 V at 100 mA cm −2 , achieving high Faradaic efficiencies (>96%) for H 2 production, while also exhibiting remarkable durability over 1 month (838 h). This work paves the way for the development of highly efficient and durable supported catalysts, enabling energy‐saving hydrogen production and environmentally friendly sulfion recycling.