Electrochemical C-N coupling of carbon dioxide and oxynitride under ambient environment is an emerging approach which promisingly enables sustainable production of valuable industrial chemicals, such as amines and their derivatives. However, the understanding of the C-N coupling is still in its infancy. Herein, we reported highly efficient electrochemical co-reduction of carbon dioxide and nitrate to form urea catalyzed by AuPd nanoalloy. Faradic efficiency and urea formation rate achieved 15.6% and 204.2 μg·mg⁻¹·h⁻¹, respectively, in a gas-tight H-type cell under ambient environment. The DFT studies on the C-N coupling mechanism showed that hydroxylamine was the most likely C-N coupling N-intermediate among many nitrogen-containing intermediates and that *NH₂OH and *CO, rather than *NH₂ and *CO, were confirmed to realize the C-N coupling to form urea through a one-step synergistic coupling which is a thermodynamically spontaneous process with a low activation barrier. This work not only provides new insights into the C-N coupling of oxynitride and carbon dioxide under ambient environment, but also may pave a way for promoting sustainable production of C-N coupling products.

环境环境下二氧化碳和氧氮化物的电化学 CN 偶联是一种新兴的方法，有望实现有价值的工业化学品的可持续生产，例如胺及其衍生物。然而，对CN耦合的理解仍处于起步阶段。在此，我们报道了由 AuPd 纳米合金催化的二氧化碳和硝酸盐的高效电化学共还原形成尿素。在环境环境下的气密H型电池中，法拉第效率和尿素形成率分别达到15.6%和204.2 μg·mg ^-1 ·h ^{-1 。}CN 偶联机理的 DFT 研究表明，羟胺是众多含氮中间体中最可能的 CN 偶联 N 中间体，*NH ₂OH和*CO，而不是*NH ₂和*CO，被证实通过一步协同偶联实现CN偶联形成尿素，这是一种具有低活化势垒的热力学自发过程。该工作不仅为环境环境下氧氮化物和二氧化碳的CN偶联提供了新的见解，也可能为促进CN偶联产品的可持续生产铺平道路。