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Efficient urea electrosynthesis from CO2 and nitrate mediated by an ionic liquid bridge

Nature Sustainability volume 9, pages 108–116 (2026)Cite this article

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Abstract

The electrochemical co-reduction of abundant carbon dioxide (CO2) and nitrates (NO3−) offers a more sustainable strategy for synthesizing urea, which is a critical nitrogen source for fertilizers. However, constrained proton-coupled electron transfer and limited opportunity for C–N coupling lead to a low urea production rate. In this work, we incorporated ionic liquid and copper [Cu(II)] into the zeolitic imidazolate framework-8 to create the IL@Cu-ZIF-8 catalyst. The as-prepared catalyst demonstrates excellent performance for the co-reduction of CO2 and NO3− to urea. At −0.5 V versus the reversible hydrogen electrode, the production rate of urea can reach 140 μmol h−1 cm−2 (~42,000 mg h−1 gcat−1), with a Faradaic efficiency toward urea of 55.3%. A total of 0.53 g of pure urea was generated over a 25-cm2 IL@Cu-ZIF-8 electrode after 5 h of electrolysis. Mechanism studies show that ionic liquid within the catalyst acts as a molecular bridge, linking the active centres of the catalyst and reactants through versatile interactions, which increases the concentration of surface reactants and reduces the proton-coupled electron transfer barrier, thereby promoting C–N coupling for urea synthesis. This work introduces an efficient strategy for urea electrosynthesis with a high production rate, representing a significant step toward scalable electrochemical synthesis of nitrogen-containing compounds.

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Fig. 1: Characterizations of Cu-ZIF-8 and IL-Cu-ZIF-8.
Fig. 2: Electrosynthesis urea over different electrodes in 1 M KOH + 0.1 M KNO3.
Fig. 3: Investigations of Cu-ZIF-8 and IL@Cu-ZIF-8 in 1 M KOH + 0.1 M KNO3.
Fig. 4: DFT calculations.

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The data supporting the findings of this study are available within the article and Supplementary Information. Source data are provided with this paper.

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Acknowledgements

We thank the National Natural Science Foundation of China (grant nos. 22273108, 22033009, 22293015 and 22121002), the Beijing Natural Science Foundation (grant no. 2222043), the CAS Project for Young Scientists in Basic Research (grant no. YSBR-050), the ICCAS Carbon Neutral Chemistry Program (grant no. CCNC-202403), the Youth Innovation Promotion Association CAS (grant no. Y2022017) and the National Key Research and Development Program of China (grant no. 2023YFA1507400) for their financial support of this research. We thank the 1W1A and 1W2B beamlines of the Beijing Synchrotron Radiation Facility for providing technical support and assistance in SXRD and X-ray absorption spectroscopy data collection, respectively.

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  1. These authors contributed equally: Yaoyu Yin, Zhongnan Ling.

Authors and Affiliations

  1. Beijing National Laboratory for Molecular Sciences, CAS Laboratory of Colloid and Interface and Thermodynamics, CAS Research/Education Center for Excellence in Molecular Sciences, Center for Carbon Neutral Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, China

    Yaoyu Yin, Shiqiang Liu, Yiyong Wang, Wenling Zhao, Hengan Wang, Jiahao Yang, Rongjuan Feng, Shipeng Zhang, Lihong Jing, Qinggong Zhu, Xiaofu Sun, Jianling Zhang, Xinchen Kang & Buxing Han

  2. School of Chemistry and Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China

    Yaoyu Yin, Yiyong Wang, Wenling Zhao, Hengan Wang, Jiahao Yang, Qinggong Zhu, Xiaofu Sun, Jianling Zhang, Xinchen Kang & Buxing Han

  3. Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, China

    Zhongnan Ling & Xueqing Xing

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Contributions

Y.Y. and Z.L.: syntheses and characterizations of catalysts. S.L, Y.W. and W.Z.: urea electrosynthesis experiments. H.W. and J.Y.: MD and DFT simulations. R.F., S.Z. and X.X.: collection and analysis of in situ ATR-SEIRAS spectra data. L.J., Q.Z., X. S. and J.Z.: mechanism analysis. X.K. and B.H.: overall design and direction of the project. Y.Y., X.K. and B.H.: preparation of the manuscript, with help from all authors.

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Correspondence to Xinchen Kang or Buxing Han.

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Nature Sustainability thanks Liangzhi Kou and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Yin, Y., Ling, Z., Liu, S. et al. Efficient urea electrosynthesis from CO2 and nitrate mediated by an ionic liquid bridge. Nat Sustain 9, 108–116 (2026). https://doi.org/10.1038/s41893-025-01703-9

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