Steering Intermediate Coupling by Alkali‐Metal Cations for Efficient Nitrate Electroreduction to Ammonia

ABSTRACT The electrocatalytic nitrate reduction reaction (eNO 3 − RR) provides a sustainable pathway for ammonia synthesis and nitrate wastewater remediation, yet its efficiency is fundamentally limited by the sluggish kinetics of the multistep conversion process. Herein, we elucidate how alkali‐metal cations regulate the interfacial microenvironment to boost the ammonia production performance of eNO 3 − RR. Using winged carbon coaxial nanocables as model catalysts, among the alkali‐metal cations investigated, Cs + enhances the local electric field that strengthens the adsorption of *NO x intermediates, whereas Li + more effectively promotes the interfacial water reorganization to facilitate adsorbed hydrogen atom ( * H) formation. Crucially, Na + achieves the most favorable balance between these two complementary processes, thereby enabling efficient coupling between *NO x intermediates and *H throughout the nitrate reduction pathway. This balanced interplay delivers an NH 3 yield rate of 94.9 g h −1 g cat. −1 in a Na + ‐mediated neutral electrolyte. The strategy exhibits broad applicability across diverse electrolytes and catalyst systems, offering a general design principle for steering complex hydrogenation‐related catalytic transformations via rational electrolyte engineering.