Efficient and sustainable urea synthesis on a bifunctional catalyst

Electrochemical co-reduction of CO₂ and nitrogen sources (N₂ or NO₃⁻) provides a promising route for ambient urea synthesis, yet suffers from low conversion efficiency or reliance on fossil fuel-derived NH₃/NO₃⁻. Herein, we present an integrated plasma-electrocatalytic route for sustainable urea synthesis from ambient air, which involves the initial plasma-driven air oxidation to form NO_<i>x</i>⁻ and followed by electrocatalytic co-reduction of CO₂ + NO_<i>x</i>⁻ to produce urea. Specially, a bifunctional Bi_SA/<i>a</i>-MoO₃ catalyst (isolated Bi single atom on amorphous MoO₃) was designed to promote both plasma and electrocatalytic processes, consequently achieving the exceptional urea yield rate of 55.9 mmol·h⁻¹·g⁻¹ and Faradaic efficiency of 59.7%. The combined theoretical calculations and <i>in situ</i> spectroscopic measurements reveal the synergy of Bi_SA and unsaturated Mo sites in boosting the C–N coupling of *COOH and *NH₂ intermediates for selective urea formation.