Abstract
During the chlor-alkali process, in operation since the nineteenth century, electrolysis of sodium chloride solutions generates chlorine and sodium hydroxide that are both important for chemical manufacturing1,2,3,4. As the process is very energy intensive, with 4% of globally produced electricity (about 150 TWh) going to the chlor-alkali industry5,6,7,8, even modest efficiency improvements can deliver substantial cost and energy savings. A particular focus in this regard is the demanding chlorine evolution reaction, for which the state-of-the-art electrocatalyst is still the dimensionally stable anode developed decades ago9,10,11. New catalysts for the chlorine evolution reaction have been reported12,13, but they still mainly consist of noble metal14,15,16,17,18. Here we show that an organocatalyst with an amide functional group enables the chlorine evolution reaction; and that in the presence of CO2, it achieves a current density of 10 kA m−2 and a selectivity of 99.6% at an overpotential of only 89 mV and thus rivals the dimensionally stable anode. We find that reversible binding of CO2 to the amide nitrogen facilitates formation of a radical species that plays a critical role in Cl2 generation, and that might also prove useful in the context of Cl− batteries and organic synthesis19,20,21. Although organocatalysts are typically not considered promising for demanding electrochemical applications, this work demonstrates their broader potential and the opportunities they offer for developing industrially relevant new processes and exploring new electrochemical mechanisms.
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Acknowledgements
This work was supported by the National Key R&D Program of China (2018YFA0702003), the National Natural Science Foundation of China (22171157, 21890383 and 21871159) and the Science and Technology Key Project of Guangdong Province of China (2020B010188002). We acknowledge help from J. Shui.
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J.Y., W.-H.L., D.W. and Y.L. conceived the idea, designed the study, planned synthesis and wrote the paper. J.Y. and W.-H.L. analysed the data and wrote the paper. W.-H.L., Y.-M.P. and H.-T.T. synthesized the catalysts. J.Y. and W.-H.L. characterized the catalysts. J.Y. carried out the electrochemical experiments. J.Y. carried out the theoretical calculation. J.Y., W.-H.L. and H.-T.T. contributed equally to this work.
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This file includes Supplementary Sections 1–18, Figs. 1–79, Tables 1–3 and References. Further information and data on synthesis, structural characterization, detailed electrochemical analysis, homogeneous tests, analyses of molecules after the reaction, and theoretical calculations are listed.
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Yang, J., Li, WH., Tang, HT. et al. CO2-mediated organocatalytic chlorine evolution under industrial conditions. Nature 617, 519–523 (2023). https://doi.org/10.1038/s41586-023-05886-z
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DOI: https://doi.org/10.1038/s41586-023-05886-z
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