Twin-Boundary Cu2-Pair Pockets Drive Spatial Proximity of Key Intermediates for Efficient Urea Electrosynthesis.

Electrocatalytic urea synthesis from carbon dioxide (CO2) and nitrate (NO3 -) offers an alternative to the energy-intensive Bosch-Meiser process but is limited by poor selectivity and Faradaic efficiency (FE). Herein, we proposed a defect engineering strategy by constructing ordered Cu nanowire electrocatalysts enriched with abundant twin boundaries (TBs) that can drive spatial proximity between the key intermediates derived from asymmetric activation of CO2 and optimized adsorption of NO3 -. Specifically, it could achieve a high FE of 61.81% and a peak yield rate of 5.80 mg h-1 cm-2 for urea production under a three-electrode configuration. The underlying mechanism can be described as the TB-induced compression shortening the Cu-Cu bond, creating Cu2-pair pockets that geometrically matched CO2 adsorption and enabled asymmetric activation to *CO, further strengthening Cu → CO π back-donation and building a *CO reservoir. Smoluchowski smoothing rendered ridge Cu sites electron-deficient, enriching NO3 - near Cu2-pair pockets for C-N coupling.