Fabrication of an Au₂₅ -Cys-Mo Electrocatalyst for Efficient Nitrogen Reduction to Ammonia under Ambient Conditions

Electrocatalysts for efficient production of ammonia from nitrogen reduction reaction (NRR) under ambient conditions are attracted growing interest in recent years, which demonstrate a great potential to replace the Haber-Bosch method which suffers the problems of the huge energy consumption and massive CO₂ production. In this work, a novel electrocatalyst of Au₂₅ -Cys-M is fabricated for NRR under ambient conditions, with transition metal ions (e.g., Mo⁶⁺ , Fe³⁺ , Co²⁺ , Ni²⁺ ) atomically decorated on Au₂₅ nanoclusters via thiol bridging. The Au₂₅ -Cys-Mo catalyst exhibits the highest Faradaic efficiency (26.5%) and NH₃ yield (34.5 µg h^-1  mg_cat ^-1 ) in 0.1 m HCl solution. X-ray photoelectron spectroscopy analysis and high angle annular dark field image-scanning transmission electron microscopy characterization reveal that the electronic structure of Mo is optimized by forming the structure of Au-S-Mo and Mo acts as active sites for activating the nitrogen to promote the electrochemical production of ammonia. This work provides a new insight into the precise fabrication of efficient NRR electrocatalysts.