Selective electrosynthesis of urea from nitrate and carbon dioxide with low overpotential.

Reducing the energy cost and CO2 emission of traditional urea synthesis through alternative strategy is crucial for the sustainable social development. Herein, we report the electrosynthesis of urea from nitrate and CO2 on Ag/CdO heterostructured catalyst with low overpotential. The optimized Ag0.07/CdO catalyst demonstrates a high urea yield rate of 111.6 ± 3.1 mmol gcat.-1 h-1 with 50.0 ± 2.7% Faradaic efficiency at -0.15 V vs. RHE in a flow cell, and can further achieve a urea yield rate of 427.0 ± 30.2 mmol gcat.-1 h-1 in an optimized two-electrode cell with stable response for 1000 h. Operando spectroscopy and theoretical calculations indicate that Ag attracts *NO2 intermediate as well as promotes the reconstruction of CdO into low coordinated CdCO3 that facilitate the activation of CO2, thus benefits *CO/*NO2 adsorption and coupling at low overpotential as well as suppresses the generation of CO and NH3 by-products.