Highly Efficient Electrocatalytic Synthesis of Urea by Coactivation of NO and CO on the SnS ₂ -Based Single-Cluster Catalysts Unraveled by DFT Study

Electrocatalytic C–N coupling for urea synthesis offers a sustainable approach for nitrogen cycling and carbon neutrality yet faces challenges on efficiency and selectivity. With definitely designed SnS 2 -supported single cluster catalyst (Pd 3 @SnS 2 and Rh 3 @SnS 2 ) as the electrocatalyst, we proposed a dual C–N bond synchronous formation mechanism utilizing NO as the nitrogen source and CO as the carbon source. Through density functional theory (DFT) calculations, we systematically elucidated the reaction mechanism of electrochemical urea synthesis. Notably, Pd 3 @SnS 2 exhibits exceptional catalytic performance, achieving an ultralow limiting potential ( U L ) of −0.08 V and a low C–N coupling Gibbs activation energy barrier of only 0.71 eV. Furthermore, crystal orbital Hamilton population (COHP) analysis revealed that the moderate Pd–N bond strength in Pd 3 @SnS 2 is the key factor underlying its high activity, which not only facilitates activation of reactant but also reduces the formation energy barrier of the key intermediate *ONCONO.