Effect on electrochemical reduction of nitrogen to ammonia under ambient conditions: challenges and opportunities for chemical fuels

Abstract The nitrogen cycle plays an important role in nature, but N-containing products cannot meet human needs. The electrochemical synthesis of ammonia under ambient conditions has attracted the interest of many researchers because it provides a clean and pollution-free synthesis method; however, it has certain difficulties, including a high activation energy, multiple electron transfer, and hydrogenation. Thermodynamic factors limit the selectivity and activity of ammonia synthesis techniques. This review summarizes progress in the electrochemical synthesis of ammonia from theory and experiment. Theoretically, the reduction of nitrogen molecules is analyzed using orbit theory and the thermodynamic reaction pathways. Experimentally, we first discuss the effect of the experimental setup on the nitrogen reduction reaction, and then the four critical of catalysts, including size, electronic, coordination, and orientation effects. These issues must be considered to produce highly-efficient catalysts for electrochemical nitrogen reduction (eNRR). This review provides an overview of the eNRR to enable future researchers to design rational catalysts.