High-Throughput Theoretical Screening of Single-Atom Catalysts for Electrochemical Urea Synthesis

Electrochemical urea synthesis offers a promising approach for sustainable nitrogen and carbon utilization, yet its progress is hindered by the unclear reaction mechanism and the lack of effective catalyst design principles. Here, we conduct a high-throughput screening of over 40 MN₄C-type single-atom catalysts (SACs) to identify promising candidates for electrochemical urea synthesis. This strategy improves screening efficiency by 94.8% compared to conventional methods. Our analysis demonstrates that Ti─, V─, Nb─, Mo─, and Hf–N₄C catalysts concurrently fulfill the essential criteria, including thermodynamic stability, favorable adsorption of small molecules, suppression of competing reactions, and low energy barriers for both hydrogenation and C–N coupling. Mechanistic investigations reveal two distinct C–N coupling pathways and demonstrate that hydrogenation of *N species is a prerequisite for subsequent coupling. Notably, we reveal a linear correlation between the limiting potentials of NO₃⁻ reduction and overall urea synthesis, establishing *NO₃ → *N activity as a reliable descriptor for catalyst screening. This work provides mechanistic insights and a predictive framework for the rational design of efficient urea electrocatalysts.