CoCuSiB Nanocrystalline for Efficient Nitrate-to-Ammonia Electroreduction

Electrocatalytic nitrate reduction reaction (NO₃RR) represents a dual-function route for sustainable ammonia synthesis and wastewater treatment. Yet, the practical application of this process is currently hindered by unsatisfactory electrocatalytic activity and long-term stability. Herein, Co₆₀Cu₁₂Si₁₈B₁₀ nanocrystalline alloy with a unique Cu-CoSiB dual nanocrystalline structure was fabricated through nonequilibrium solidification technology. The addition of Si and B not only promotes geometric structural refinement but also modulates the electronic structure of the active sites. The resultant Co₆₀Cu₁₂Si₁₈B₁₀ catalyst achieves excellent NO₃RR performance with an NH₃ yield rate of 9.11 mg h^-1 cm^-2 and a NH₃ Faradaic efficiency (FE) of 96.4% in 0.1 M NO₃^- electrolytes, outperforming most of the reported catalysts. This work demonstrates that nonmetallic alloyed nanocrystals enable highly efficient electrocatalysis, highlighting their promise for economically and environmentally treating wastewater into valuable NH₃ and energy storage.