Kinetically matched C–N coupling toward efficient urea electrosynthesis enabled on copper single-atom alloy
Mengqiu Xu, Fangfang Wu, Ye Zhang, Yuanhui Yao, Genping Zhu, Xiaoyu Li, Liang Chen, Gan Jia, Xiaohong Wu, Youju Huang, Peng Gao, Wei Ye
Abstract
Abstract Chemical C–N coupling from CO 2 and NO 3 – , driven by renewable electricity, toward urea synthesis is an appealing alternative for Bosch–Meiser urea production. However, the unmatched kinetics in CO 2 and NO 3 – reduction reactions and the complexity of C- and N-species involved in the co-reduction render the challenge of C–N coupling, leading to the low urea yield rate and Faradaic efficiency. Here, we report a single-atom copper-alloyed Pd catalyst (Pd 4 Cu 1 ) that can achieve highly efficient C–N coupling toward urea electrosynthesis. The reduction kinetics of CO 2 and NO 3 – is regulated and matched by steering Cu doping level and Pd 4 Cu 1 /FeNi(OH) 2 interface. Charge-polarized Pd δ– -Cu δ+ dual-sites stabilize the key *CO and *NH 2 intermediates to promote C–N coupling. The synthesized Pd 4 Cu 1 -FeNi(OH) 2 composite catalyst achieves a urea yield rate of 436.9 mmol g cat. –1 h –1 and Faradaic efficiency of 66.4%, as well as a long cycling stability of 1000 h. In-situ spectroscopic results and theoretical calculation reveal that atomically dispersed Cu in Pd lattice promotes the deep reduction of NO 3 – to *NH 2 , and the Pd-Cu dual-sites lower the energy barrier of the pivotal C–N coupling between *NH 2 and *CO.