Coupling N₂ and CO₂ in H₂O to synthesize urea under ambient conditions

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.