Boosting Up Electrosynthesis of Urea with Nitrate and Carbon Dioxide via Synergistic Effect of Metallic Iron Cluster and Single-Atom.

Electrocatalytic conversion of nitrates and carbon dioxide to urea under ambient conditions shows promise as a potential substitute for traditional urea synthesis processes characterized by high consumption and pollution. In this study, a straightforward one-pot method is employed to prepare a highly efficient FeNC-Fe 1 N 4 electrocatalyst, consisting of atomically dispersed Fe 1 N 4 sites and metallic Fe clusters (FeNC) with particle size of 4-7 nm. The FeNC-Fe 1 N 4 catalyst exhibits remarkable electrocatalytic activity for urea synthesis from nitrate anion (NO 3 - ) and carbon dioxide (CO 2 ), achieving a urea production rate of 38.2 mmol g cat -1  h -1 at -0.9 V (vs RHE) and a Faradaic efficiency of 66.5% at -0.6 V (vs RHE). Both experimental and theoretical results conclusively demonstrate that metallic Fe clusters and Fe 1 N 4 species provide active sites for the adsorption and activation of NO 3 - and CO 2 , respectively, and the synergistic effect between Fe 1 N 4 and metallic Fe clusters significantly enhances the electrochemical efficiency of urea synthesis. In all, this work contributes to the rational design and comprehensive synthesis of a dual-active site iron-based electrocatalyst, facilitating efficient and sustainable urea synthesis.