Dual-metal active site catalysts for electrocatalytic nitrate reduction to ammonia

Ammonia plays a foundational role in modern agriculture and has also been regarded as a next-generation carbon-free fuel with high energy intensity. The conventional Haber-Bosch process for ammonia synthesis suffers from high energy consumption and large CO₂ emission. Meanwhile, the accumulation of nitrate in water bodies, primarily originating from industrial effluents and chemical fertilizers, can lead to severe pollution and pose a significant threat to public health. In recent years, the nitrate electroreduction reaction (NO₃RR) has attracted considerable attention owing to its significant potential for simultaneously eliminating nitrates and producing ammonia. Dual-metal active site catalysts (DMCs) demonstrate significant potential in NO₃RR, due to their multiple active sites, distinctive electronic structures, and high structural tunability. This review firstly elaborates the reaction mechanisms of NO₃RR, followed by an in-depth examination of recent advancements in dual-metal active site catalysts for NO₃RR. Emphasis is placed on discussing their advantages, operational mechanisms, and structure-performance relationships. Finally, the challenges and potential opportunities of dual-metal active site catalysts for NO₃RR are proposed.