Sequential co-reduction of nitrate and carbon dioxide enables selective urea electrosynthesis
Yang Li, Shisheng Zheng, Hao Liu, Qi Xiong, Haocong Yi, Haibin Yang, Zongwei Mei, Qinghe Zhao, Zu‐Wei Yin, Ming Huang, Yuan Lin, Weihong Lai, Shi Xue Dou, Feng Pan, Shunning Li
Abstract
Abstract Despite the recent achievements in urea electrosynthesis from co-reduction of nitrogen wastes (such as NO 3 − ) and CO 2 , the product selectivity remains fairly mediocre due to the competing nature of the two parallel reduction reactions. Here we report a catalyst design that affords high selectivity to urea by sequentially reducing NO 3 − and CO 2 at a dynamic catalytic centre, which not only alleviates the competition issue but also facilitates C−N coupling. We exemplify this strategy on a nitrogen-doped carbon catalyst, where a spontaneous switch between NO 3 − and CO 2 reduction paths is enabled by reversible hydrogenation on the nitrogen functional groups. A high urea yield rate of 596.1 µg mg −1 h −1 with a promising Faradaic efficiency of 62% is obtained. These findings, rationalized by in situ spectroscopic techniques and theoretical calculations, are rooted in the proton-involved dynamic catalyst evolution that mitigates overwhelming reduction of reactants and thereby minimizes the formation of side products.