Urea Electrosynthesis from Nitrate and CO<sub>2</sub> on Diatomic Alloys
Kai Chen, Danyang Ma, Ying Zhang, Fuzhou Wang, Xing Yang, Xiaomei Wang, Hu Zhang, Xijun Liu, Rui Bao, Ke Chu
Abstract
Abstract Urea electrosynthesis from co–electrolysis of NO 3 − and CO 2 (UENC) offers a promising technology for achieving sustainable and efficient urea production. Herein, a diatomic alloy catalyst (CuPd 1 Rh 1 –DAA), with mutually isolated Pd and Rh atoms alloyed on Cu substrate, is theoretically designed and experimentally confirmed to be a highly active and selective UENC catalyst. Combining theoretical computations and operando spectroscopic characterizations reveals the synergistic effect of Pd 1 –Cu and Rh 1 –Cu active sites to promote the UENC via a tandem catalysis mechanism, where Pd 1 –Cu site triggers the early C–N coupling and promotes *CO 2 NO 2 –to–*CO 2 NH steps, while Rh 1 –Cu site facilitates the subsequent protonation step of *CO 2 NH 2 to *COOHNH 2 toward the urea formation. Impressively, CuPd 1 Rh 1 –DAA assembled in a flow cell presents the highest urea Faradaic efficiency of 72.1% and urea yield rate of 53.2 mmol h −1 g cat −1 at −0.5 V versus RHE, representing nearly the highest performance among all reported UENC catalysts.