Ambient electrocatalytic synthesis of urea by co-reduction of NO3− and CO2 over graphene-supported In2O3

Urea plays a vital role in the sustainable development of mankind as it is one of the most important nitrogen fertilizers. Conventional synthesis of urea is accompanied by a high level of energy consumption while electrocatalytic methods suffer from low yields and poor selectivity. Our work achieves efficient synthesis of urea by designing the graphene-In2O3 electrocatalysts for the co-activated reduction of nitrate and carbon dioxide, where the formation rate of urea, Faraday efficiency (FE) and carbon selectivity at -0.35 V vs. RHE can reach 357.47 µg mg−1 h−1, 10.46% and ∼100%, respectively. Herein, the key intermediates in the CN coupling reaction are demonstrated to be *NH2 and *CO2, which is of novelty compared to previous reports. This work may provide inspiration for subsequent studies on the reaction mechanism of the electrochemical synthesis of urea, as well as theoretical guidance for the sustainable synthesis of some other important chemical substances.