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

Abstract

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-Fe₁N₄ electrocatalyst, consisting of atomically dispersed Fe₁N₄ sites and metallic Fe clusters (FeNC) with particle size of 4-7 nm. The FeNC-Fe₁N₄ catalyst exhibits remarkable electrocatalytic activity for urea synthesis from nitrate anion (NO₃ ^-) and carbon dioxide (CO₂), 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 Fe₁N₄ species provide active sites for the adsorption and activation of NO₃ ^- and CO₂, respectively, and the synergistic effect between Fe₁N₄ 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.