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.

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Fig. 1: Morphology and high-resolution XPS spectra of catalysts.
Fig. 2: Evaluation of the electrocatalytic performance of Pd1Cu1/TiO2-400 in a flow cell.
Fig. 3: Sorption of gaseous molecules on catalysts.
Fig. 4: Isotope-labelling operando SR-FTIR spectroscopy measurement results.
Fig. 5: Theoretical calculation results for urea synthesis.

Data availability

All data generated or analysed during this study are included in this Article (and its Supplementary Information). Data for Figs. 1–5 are available as source data with this paper.

Code availability

The computational codes used in the current work are available from the corresponding author on reasonable request.


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We thank the National Natural Science Foundation of China (grant no. 21573066, 21825201, U1932212, U19A2017) and ARC DP170102320.

Author information




S.W. conceived the project. C.C. and Y.Z. carried out most of the experiments and co-wrote the manuscript. X.Z., X.W., Y.L. and J.C. performed the theoretical calculations. Q.L., H.S., X.Z. and W.C. carried out the isotope-labelling operando SR-FTIR measurements. L.Z., L.T., H.L., Q.L., S.D., T.L., D.Y. and C.X. conducted part of the synthesis of catalysts and characterizations. Y.Z., Y.W., R.C. and J.H. analysed the data. H.L., J.L., J.C. and M.D. performed the partial characterizations of materials. K.C. and C.L. performed the collection and analysis of NMR spectra. All authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Yafei Li or Jun Cheng or Qinghua Liu or Jun Chen or Shuangyin Wang.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–43, Tables 13 and refs. 1–4.

Source data

Source Data Fig. 1

High-resolution XPS spectra of catalysts.

Source Data Fig. 2

Evaluation of the electrocatalytic performance of Pd1Cu1/TiO2-400 in a flow cell.

Source Data Fig. 3

Sorption of gaseous molecules on catalysts.

Source Data Fig. 4

Isotope-labelling operando SR-FTIR spectroscopy measurement results.

Source Data Fig. 5

Theoretical calculation results for urea synthesis.

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Chen, C., Zhu, X., Wen, X. et al. Coupling N2 and CO2 in H2O to synthesize urea under ambient conditions. Nat. Chem. 12, 717–724 (2020).

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