Screening Single-Atom-Doped Transition Metal CuFe Alloy Catalysts for Electrochemical Urea Synthesis

Electrochemical C–N coupling offers a sustainable route for the synthesis of urea from CO2 and N2. However, it is challenged by the scarcity of active and highly selective catalysts. In this study, we present a rational strategy to design transition metal (TM)-doped single-atom alloy (SAA) electrocatalysts. We investigated a CuFe bimetallic alloy as a host to enable facile coactivation of CO2 and N2. Through a multistep process using quantum mechanical calculations, 3d, 4d, and 5d TM dopants on the CuFe surface were screened to assess catalyst synthesizability, activity, and selectivity against competing pathways, including hydrogen evolution reaction, ammonia formation, and C2 product formation. Among all TMs, Ti, Cr, Mo, and W were identified as promising candidates that can form thermodynamically stable SAAs in the CuFe bimetallic alloy. W-doped CuFe emerged as the most selective and favorable candidate for urea production, and the electronic structure analysis revealed the origin of the high selectivity. While Cr and Ti catalysts showed overbinding due to high d-band centers, strong hybridization, and excessive charge transfer, the W dopant achieves an optimal electronic balance, enabling controlled back-donation to both N2 and CO2 molecules, facilitating dual activation. Mechanistic investigation revealed the reaction pathway involving a C–N coupling step to form the *NCON intermediate, with an activation free-energy barrier of 1.08 eV on W SAA. Cr, Mo, and Ti were relatively less active and selective. This work presents a rational strategy for designing SAAs for targeted C–N bond formation.