Decoupling Activity and Selectivity in Electrochemical Urea Synthesis via a Descriptor-Based Framework

Abstract Electrochemical urea synthesis via the co-reduction of CO2 and nitrogen-containing species offers an alternative route under mild conditions to conventional thermochemical processes, but remains limited by poor mechanistic understanding and the lack of general design principles. Here, using NO2– as the nitrogen source, we develop a unified descriptor-based framework for electrochemical urea synthesis based on systematic density functional theory calculations across a series of metal catalysts. We identify the adsorption free energies of *COOH and *N as distinct descriptors governing selectivity and activity, respectively. This descriptor-based decoupling reveals that intrinsic scaling relations impose a fundamental constraint on pure-metal catalysts, leading to an intrinsic activity–selectivity trade-off consistent with experimental observations. By linking these descriptors to the energetics of early C–N coupling and potential-limiting proton-coupled electron transfer steps, we establish a mechanistic foundation for understanding catalytic performance. Guided by this framework, we demonstrate that multi-site catalyst design, alloying, and strain engineering provide viable strategies to address these limitations. In particular, alloying enables deviations from pure-metal scaling relations, unlocking regions of improved catalytic performance inaccessible to pure metals. Strain, in contrast, modulates adsorption energetics within the existing descriptor space, providing additional control over activity with minimal impact on selectivity. These insights define general design principles for electrochemical urea synthesis and provide a pathway toward the rational development of catalysts with independently tunable activity and selectivity.