Boosting Electroreduction of Nitrate and CO 2 to Urea on a Tandem Fe 1 /MoS 2 Catalyst

Urea electrosynthesis by coelectrolysis of NO 3 – and CO 2 (UENC) holds enormous promise for sustainable urea production, while the efficient UENC process relies on the rational design of high-performance catalysts to facilitate the electrocatalytic C–N coupling efficiency and the hydrogenation reaction process. Herein, Fe single atoms supported on MoS 2 (Fe 1 /MoS 2 ) are developed as a highly effective and robust catalyst for UENC. Theoretical calculations and operando spectroscopic measurements reveal a tandem catalysis mechanism of the Fe 1 –S 3 motif and MoS 2 -edge to jointly promote the UENC process, where the Fe 1 –S 3 motif drives the early C–N coupling and subsequent *CO 2 NO 2 -to-*CO 2 NH 2 step. The generated *CO 2 NH 2 is then migrated from the Fe 1 –S 3 motif to the nearby MoS 2 -edge, which facilitates the *CO 2 NH 2 → *COOHNH 2 step for urea formation. Noticeably, Fe 1 /MoS 2 assembled in a flow cell reaches a maximum urea Faraday efficiency of 54.98% with a corresponding urea yield rate of 18.98 mmol h –1 g –1, performing at the top level among all of the UENC catalysts reported to date.