Nitrate Electroreduction to Ammonia over Copper-based Catalysts.

The electrocatalytic reduction of nitrate (NO3-) to ammonia (NH3) holds substantial promise, as it transforms NO3- from polluted water into valuable NH3. However, the reaction is limited by sluggish kinetics and low NH3 selectivity. Cu-based catalysts with unique electronic structures demonstrate rapid NO3- to NO2- rate-determining step (RDS) and fast electrocatalytic nitrate reduction reaction (eNO3RR) kinetics among non-noble metal catalysts. Nonetheless, achieving high robustness and selectivity for NH3 with Cu-based catalysts remains a significant challenge. This review provides a comprehensive overview of the reaction mechanisms in eNO3RR, highlights how the structures of monometallic and bimetallic Cu-based catalyst affect catalytic properties, and discusses the current challenges as well as prospects in eNO3RR.