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-In2 O3 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 mu g mg-1 h-1 , 10.46% and similar to 100%, respectively. Herein, the key intermediates in the C-N 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. (c) 2024 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.