Ionic Liquid Microenvironment Modulation for Promoting Electrocatalytic C–N Coupling and Urea Synthesis over Zn@Cu

Abstract Urea electrosynthesis is a promising way to upgrade traditional urea production, which is characterized by high energy consumption and significant CO2 emissions. However, its practical implementation is hindered by the relatively low production rate as well as Faradaic efficiency (FE) toward urea. Herein, a strategy to boost the electrocatalytic urea production is proposed by using a surface-anchored ionic liquid (IL) to stabilize the C–N coupling reaction intermediates via a hydrogen bond. A urea yield of 25.7 μmol h–1 cm–2 and an FE of 30.2% at –1.1 V vs Ag/AgCl are reached over [BIm]NTf2-Zn@Cu using CO2 and NO2– as feedstocks, which outperforms the recently reported similar catalysts in the literature. In situ infrared spectroscopy and theoretical calculations reveal that the IL creates an electron-rich microenvironment and enriches the existence of activated CO2 and NO2– near the surface. The lower energy barriers for the formation of key intermediates *CO and *NH2 facilitate C–N coupling to produce urea in both high productivity and selectivity.