Low-Overpotential Urea Electrosynthesis via Nitrate Reduction-Assisted Carbon Fixation on Bimetallic CuZn Sites

Ambient electrosynthesis urea using NO 3 –, CO 2, and H 2 O has emerged as an alternative to the current energy-intensive industrial synthesis process while storing renewable energy. Unfortunately, C–N coupling reaction kinetics are sluggish due to difficult CO 2 activation/conversion, along with strong side reactions, leading to high overpotential, low selectivity, and consequently low yield. Here, to avoid the competitive CO 2 and NO 3 – reduction and the high overpotential of CO 2 reduction in the traditional Langmuir–Hinshelwood route via C/N intermediates, we developed an effective C–N coupling strategy via the Eley–Rideal route, wherein prioritized NO 3 – reduction intermediates directly assisted CO 2 fixation. Using bimetallic CuZn catalysts, we achieved efficient urea production at an ultralow operating potential of –0.1 V vs RHE. The CuZn catalyst reached a maximum Faradaic efficiency of 55.2% at –0.2 V vs RHE and a considerable yield rate of 37.9 mmol h –1 g cat. –1 at –0.3 V vs RHE, surpassing its counterparts. Utilizing in/ex situ experiments and theoretical calculations, we found that favorable C–N bond formation proceeds through the direct interaction of free CO 2 with *NO intermediates on reconstructed metallic CuZn sites. This work highlights that rationally regulating C–N coupling is compelling for facilitating high-efficiency urea synthesis and other important C–N reactions.