Abstract: Excessive nitrate (NO₃⁻) contamination has emerged as a critical environmental issue owing to the widespread use of nitrogen-based fertilizers, fossil fuel combustion, and the discharge of industrial and domestic effluents. Consequently, electrochemical nitrate reduction (eNO₃R) to ammonia (NH₃) has emerged as a promising alternative to the traditional Haber-Bosch process. However, the industrial implementation of eNO₃R is hindered by low catalytic activity, poor selectivity, and limited stability owing to competing hydrogen evolution reactions. This paper provides a comprehensive overview of recent advancements in eNO₃R, particularly evaluating the catalytic activity, selectivity, and stability of both noble and non-noble metal catalysts. This review elucidates innovative catalyst design strategies, state-of-the-art developments, and potential directions for future research. Additionally, the paper explores the fundamental mechanisms underlying eNO₃R for NH₃ production, including electrocatalyst development methodologies, electrolyte effects, in situ characterization techniques, theoretical modeling, and cell design considerations. Moreover, factors influencing NH₃ selectivity and catalyst structural composition are thoroughly examined. Finally, this review provides comprehensive insights into optimizing eNO₃R processes for synthesizing NH₃, which can promote further advancements in this field.

Key words: Nitrate reduction, Electrocatalysis, NH₃production, Activity, Selectivity, Stability