Ferroelectric Heterojunction with Spatiotemporally Programmable CO Spillover Pathways Boosts Urea Electrosynthesis.

Electrochemical urea synthesis offers a sustainable strategy for the purification and resource utilization of greenhouse gases and water pollutants. However, kinetic disparities between the competing reduction pathways of CO2 and NO3- lead to spatiotemporal mismatches between C- and N-intermediates, severely hindering efficient C-N coupling. In this context, we demonstrated a strategic design of enzyme-inspired "spatial decoupling-temporal coupling" on a ferroelectric SnS-Cu0.15-TiO2 heterojunction. A high urea yield rate of 2392.5 μg h-1 mgcat-1 with a Faradaic efficiency (FE) of 71.2% outperforms the state-of-the-art electrocatalysts. Atomically dispersed Cu1 sites induce an unprecedented ferroelectricity enhancement, whereby a strengthened built-in electric field generates spatially resolved charge domains for coactivation of both CO2 and NO3-. Correlated in situ Raman and infrared spectroscopic studies disclose that the S-Cu1-O interfacial channels mediate remote *CO spillover and its dynamic, temporal coupling with *NH2. Moreover, a coupled electrolyzer integrating the electrocatalytic upcycling of wastewater-derived NO3- and Cl- achieves a remarkable 79.4% urea FE, while enabling simultaneous environmental remediation. This work highlights the unique advantages of ferroelectric heterojunctions-mediated dynamic catalysis in regulating complex reaction networks for urea electrosynthesis, opening sustainable electrochemical routes toward CO2 mitigation and the green transformation of coastal wastewater treatment.