The use of nitrogen fertilizers has been estimated to have supported 27% of the world’s population over the past century. Urea (CO(NH₂)₂) is conventionally synthesized through two consecutive industrial processes, N₂ + H₂ → NH₃ followed by NH₃ + CO₂ → urea. Both reactions operate under harsh conditions and consume more than 2% of the world’s energy. Urea synthesis consumes approximately 80% of the NH₃ produced globally. Here we directly coupled N₂ and CO₂ in H₂O to produce urea under ambient conditions. The process was carried out using an electrocatalyst consisting of PdCu alloy nanoparticles on TiO₂ nanosheets. This coupling reaction occurs through the formation of C–N bonds via the thermodynamically spontaneous reaction between *N=N* and CO. Products were identified and quantified using isotope labelling and the mechanism investigated using isotope-labelled operando synchrotron-radiation Fourier transform infrared spectroscopy. A high rate of urea formation of 3.36 mmol g^–1 h^–1 and corresponding Faradic efficiency of 8.92% were measured at –0.4 V versus reversible hydrogen electrode.

据估计，在过去的一个世纪中，氮肥的使用已为世界27％的人口提供了支持。尿素（CO（NH ₂）₂）通常通过两个连续的工业过程合成：N ₂  + H ₂  →NH _3，然后是NH ₃  + CO ₂  →尿素。两种反应均在苛刻的条件下运行，消耗了世界2％以上的能量。尿素合成消耗了全球生产的NH ₃约80％。在这里，我们直接将H _2中的N ₂和CO ₂耦合O在环境条件下产生尿素。该过程是使用由PdCu合金纳米颗粒组成的电催化剂在TiO ₂纳米片上进行的。这种偶联反应是通过* N = N *和CO之间的热力学自发反应通过形成C–N键而发生的。使用同位素标记法鉴定和定量了产物，并使用同位素标记的同步辐射-傅立叶变换红外光谱研究了机理。与可逆氢电极相比，在–0.4 V时测得的尿素形成速率高，为3.36 mmol g ^–1  h ^–1，相应的法拉第效率为8.92％。