Urea Electrosynthesis from Nitrate and CO 2 on Diatomic Alloys.

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.