Electrode-Electrolyte Engineering and In Situ Spectroscopy for Urea Electrosynthesis from Carbon Dioxide and Nitrate Co-Reduction.

The biogeochemical cycles of carbon and nitrogen are globally disturbed due to the intensive use of fossil fuels and fertilizers, which is reflected by the accumulation of carbon dioxide in the atmosphere and nitrate in water streams. The co-electroreduction of carbon dioxide and nitrate is a promising low-carbon alternative for urea synthesis that would help to reestablish both carbon and nitrogen cycles. This Perspective highlights the importance of rational catalyst and electrolyte engineering to enable electrochemical urea synthesis. Although the field has gained significant attention over the past few years, fundamental research under well-defined conditions remains underexplored. We highlight the importance of investigating structure-sensitivity and electrolyte effects on electrochemical C-N coupling through complementary in situ spectroscopy and online techniques. Model studies, including in situ surface-sensitive investigations, will be crucial to understand the molecular mechanisms and thus to rationally design more efficient systems for urea electrosynthesis, paving the way for their scalable and industrial applications.