High-Efficiency Urea Electrosynthesis Enabled by Cu-Doped WO 3 in Spatially Decoupled Two Electrolyzers

Electrocatalytic urea synthesis from NO3– and CO2 (EUNC) represents a promising approach to sustainable urea production but still suffers from low efficiency and selectivity. Herein, Cu-doped WO3 (Cu/WO3) is developed as a highly active and selective catalyst for the EUNC. Combined in situ spectroscopic analysis and theoretical computations reveal that Cu/WO3 follows a cascade EUNC pathway via NO3–/CO2 → *CO–/*NO2 → *CONO2 → *CONH2 → urea, in which Cu-dopants play a triple role in activating CO2 → *CO (W activating NO3– → *NO2), promoting C–N coupling of *CO–*NO2 for key *CONO2 formation, and boosting the proton-coupled electron transfer process toward urea synthesis. Moreover, two spatially decoupled electrolyzers are designed to overcome the kinetic CO2/NO3– activation mismatch. This decoupled system achieves an unprecedented Faradaic efficiency of 75.1% and a urea yield rate of 106.29 mmol h–1 g–1, while simultaneously enabling gram-scale urea production, thus demonstrating its significant potential for practical large-scale urea electrosynthesis.