Research Progress of Catalysts with Atomic-Scale Reactive Sites in Urea Electrosynthesis

Urea (CO(NH2)2) is the main component of nitrogen-based fertilizers and is widely used in various industries. Until now, urea production is conducted under high-temperature and high-pressure conditions, which involves a considerable carbon footprint. Urea electrosynthesis, which is powered by renewable-energy-derived electricity, has emerged as a sustainable single-step process for urea production. The development of efficient and stable catalysts is the key to improving the efficiency of urea electrosynthesis. In this review, we summarized the research progress and applications of catalysts with atomic-scale reactive sites in urea electrosynthesis. Firstly, the catalytic mechanisms of urea electrosynthesis from CO2 and various nitrogenous molecules are discussed. Then, typical electrocatalysts such as single atom electrocatalysts, dual atom electrocatalysts, clusters, atomic dopants, and vacancies, etc., are discussed. Furthermore, characterization methods for atomic-scale reactive sites are summarized. Finally, challenges and suggestions for urea electrosynthesis are proposed. We hope this review can provide some inspiration toward the development of catalysts for efficient and sustainable urea electrosynthesis.