Electrochemical synthesis of urea on reduction of carbon dioxide with nitrate and nitrite ions using Cu-loaded gas-diffusion electrode

Electrochemical C–N coupling has generated intense research interest as a promising approach to reduce carbon and nitrogen emissions and store excess renewable electricity in valuable chemicals (e.g., urea, amides, and amines). In this review, we discuss the emerging trends in electrocatalytic C–N coupling reactions using CO2 and inorganic nitrogenous species (i.e., dinitrogen (N2), nitrate (NO2−), nitrite (NO3−), and ammonia (NH3)) as raw materials. The related reaction mechanisms and potential design principles for advanced electrocatalysts are outlined. In addition, the effects of different reactors, including H-cells, membrane-based flow reactors, and membrane electrode assembly electrolyzers, on the coupling reactions are emphasized. Finally, the current challenges and future opportunities in this field are described. We aim to provide an up-to-date overview of the electrochemical C–N coupling system to advance progress toward its practical application.