Recent trends and prospects in electrochemical nitrate reduction to ammonia with an emphasis on cobalt catalysts

Ammonia is gaining recognition as a promising energy carrier due to its high energy density, ease of liquefaction, and existing robust production and distribution infrastructure, particularly within the agricultural sector. The electrochemical nitrate reduction reaction (NO₃RR), conducted under ambient conditions, offers a sustainable alternative to the energy-intensive Haber–Bosch (HB) process, addressing both environmental and energy challenges. Recent advancements in understanding catalytic mechanisms, optimizing catalytic systems, and designing advanced catalysts have substantially enhanced the efficiency of nitrate-to-ammonia conversion. Among these, cobalt (Co)-based electrocatalysts have emerged as a cost-effective and efficient alternative to noble metals, owing to their earth abundance, low cost, and favorable catalytic properties. This review provides a comprehensive overview of recent progress in NO₃RR, emphasizing Co-based electrocatalysts. It delves into NO₃RR mechanism analysis, critical considerations for system optimization, and innovative Co-based catalyst design strategies. Additionally, we explore current challenges and propose future directions for improving Co-based electrocatalyst performance, aiming to advance the rational design of efficient catalysts for sustainable ammonia synthesis.