Abstract
Alternative routes to the Haber–Bosch process are being sought to electrify ammonia synthesis. Nitric oxide can be electrocatalytically converted into ammonia, but the Faradaic efficiencies and rates of production are currently far below those needed for industrial application. Here we report a rationally designed copper–tin alloy that is highly active in the synthesis of ammonia from nitric oxide. The rate of ammonia production in a flow cell reached 10 mmol cm−2 h−1 with a Faradaic efficiency of >96% at a current density >1,400 mA cm−2, and it remained stable at >600 mA cm−2 with an ammonia Faradaic efficiency of ~90% for 135 h. The rate of ammonia production in a scaled-up electrolyser comprising a membrane electrode assembly reached ~2.5 mol h−1 with a current of 400 A at ~2.6 V. We attribute the high ammonia production rate to the enhanced intrinsic activity of the alloy; the kinetic barriers of protonation are invariably low over a range of Cu6Sn5-derived surface structures.
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Acknowledgements
This work was financially supported by the National Key Research and Development Program of China (2021YFA1500702, J.X.), the National Natural Science Foundation of China (22172156 and 22321002, J.X., and 22125205 and 92045302, G.W.), the DNL Cooperation Fund, CAS (DNL202003, J.X.), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB36030200, J.X.), the CAS Youth Innovation Promotion (Y201938, G.W.), the AI S&T Program of Yulin Branch, Dalian National Laboratory for Clean Energy, CAS (DNL-YLA202205, J.X.) and the Fundamental Research Funds for the Central Universities (20720220008, G.W.). We thank the staff at the BL14W1 beamline of the Shanghai Synchrotron Radiation Facility for their technical assistance during the XAS measurements. We also acknowledge the Photon Science Center for Carbon Neutrality.
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J.X. conceived the project and supervised the theoretical studies. G.W. supervised the experiments. H.J. performed the theoretical calculations. J.S. carried out the experiments. X.F. contributed to theoretical discussions. P.W., L.P., Y.S., R.L., K.Y. and Z.P. contributed to the experimental synthesis and electrochemical measurements. M.L., L.J., J.M. and R.S. contributed to the experimental characterizations. All authors contributed to the discussion of the manuscript and approved the paper.
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Shao, J., Jing, H., Wei, P. et al. Electrochemical synthesis of ammonia from nitric oxide using a copper–tin alloy catalyst. Nat Energy 8, 1273–1283 (2023). https://doi.org/10.1038/s41560-023-01386-6
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DOI: https://doi.org/10.1038/s41560-023-01386-6
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