Precision Single‐Atom Electrocatalyst Designed for Efficient Ammonia Conversion: Multi‐Sites Drive Bond Cleavage‐Proton Coupling Process at Low Nitrate Concentration

The electrochemical reduction of nitrate to ammonia under ambient conditions represents an effective approach for wastewater treatment and ammonia synthesis. However, the lack of purposeful design on active sites for specific catalysis in key reaction steps, make enhanced ammonia production rates a persistent bottleneck. This study introduces a molecular occupation single‐atom deposition strategy that precisely controls deposition sites, enabling the design of an efficient and selective electrocatalyst with multi active sites, featuring a unique Co─Cu─O coordination structure. At 50 mg‐N L −1 low nitrate concentration, the catalyst achieves ammonia production rate of 0.37 mmol h −1 cm −2 with a Faradaic efficiency of 96.9%. Multiple in situ techniques and theoretical calculation confirm that the Cu and Co interface sites synergy promotes N‐O bond cleavage via bond elongating for *NO 2 during the adsorption process, while ammonia molecular vacancies facilitate charge transfer for rapid proton‐coupled processes resluting in energy barrier decrease. This mechanism accelerates critical reaction steps (*NO 2 → *NO → *NOH), thereby boosting ammonia generation. The work establishes a novel pathway for precise site engineering in single‐atom electrocatalysts and offers a groundbreaking methodology for high‐efficiency NO 3 − ‐to‐NH 3 conversion.