Research Progress on Cu-Based Catalysts for Electrochemical Nitrate Reduction Reaction to Ammonia

Since the conventional Haber-Bosch ammonia synthesis loop suffers from harsh process conditions, high energy consumption, and heavy pollution, the artificial catalytic synthetic NH3 has emerged as a promising alternative method for producing NH3. Meanwhile, nitrate (NO3-) accumulation in the environment causes serious problems involving health and environmental issues. The urgent need to eliminate NO3- and produce NH3 perfectly caters to the NO3- reduction reaction (NO3RR) via an attractive electrocatalytic route. Cu-based catalysts exhibit an inhibiting effect on hydrogen evolution, rapid reduction kinetics, and stable catalytic performance, revealing remarkable advantages for NO3RR. In this review, we summarize the recent achievements of Cu-based catalysts in electrocatalytic NO3RR, discuss the detection methods for evaluating NO3RR performance, and introduce the fundamentals for understanding the thermodynamics and kinetics. This review can provide guidance and help for the rational design and development of non-noble metal catalysts in electrocatalytic NO3RR to NH3.