Abstract
Although progress has been made in producing multi-carbon products from the electrochemical reduction of CO2, the modest selectivity for ethylene (C2H4) leads to low energy efficiency and high downstream separation costs. Here we functionalize Cu catalysts with a variety of substituted aryl diazonium salts to improve selectivity towards multi-carbon products. Using computation and operando spectroscopy, we find that Cu surface oxidation state (δ+ where 0 < δ < 1) can be tuned by functionalization and that it influences the selectivity to C2H4. We report a Faradaic efficiency and a specific current density for C2H4 as large as 83 ± 2% and 212 mA cm−2, respectively, on partially oxidized Cu0.26+. Using a CO gas feed, we demonstrate an energy efficiency of ~40% with a C2H4 Faradaic efficiency of 86 ± 2%, corresponding to a low electrical power consumption of 25.6 kWh Nm−3 for the CO to C2H4 conversion reaction. Our findings provide a route towards practical electrosynthesis of C2H4 using valence engineering of copper.
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Data availability
The authors declare that the data supporting the findings of this study are available within the paper and its Supplementary Information. Source data are available at https://doi.org/10.6084/m9.figshare.24903033. Source data are provided with this paper.
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Acknowledgements
Support from the European Research Council is gratefully acknowledged, as is support from the European Union’s Horizon 2020 research and innovation programme (grant agreement number 804320) to D.V. This work was also financially supported by the Special Fund Project of Jiangsu Province for Scientific and Technological Innovation in Carbon Peaking and Carbon Neutrality (grant agreement number BK20220023), as support to D.R. We thank the National Facility ELECMI ICTS (‘Division de Microscopia Electronica’, Universidad de Cadiz, DME-UCA) for the use of TEM instrumentation. We also acknowledge funding from the European Union’s Horizon 2020 research and innovation programme (grant agreement 823717-ESTEEM3) and the Spanish Ministerio de Economia y Competitividad (PID2019-107578GA-I00), the Ministerio de Ciencia e Innovación MCIN/AEI/10.13039/501100011033 and the European Union ‘NextGenerationEU’/PRTR (RYC2021-033764-I, CPP2021-008986), as support to L.L. We also acknowledge funding from the French National Agency (ANR, JCJC programme, MONOMEANR-20-CE08-0009), as support to C.S. We acknowledge M. Rüscher, F. T. Haase and L. Bai for their help on synchrotron tests. We also acknowledge SOLEIL for provision of synchrotron radiation facilities and we would like to thank A. Zitolo for assistance in using beamline SAMBA within the proposal 20200732. XAS experiments were also performed at CLAESS beamline at ALBA synchrotron with the collaboration of ALBA staff. P. Montels and D. Valenza are acknowledged for their technical assistance with the MEA cells.
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Contributions
D.V. conceived the idea and designed the experiments. D.R. performed the DFT calculations and discussed the results with D.V. and H.W. H.W. designed the experiments with D.V., prepared the electrodes and performed the electrochemical measurements. H.W., D.R. and D.V. analysed the data and wrote the manuscript. L.H. and V.F. performed the XPS and Auger measurements and analysed the data with H.W. J.T. and H.W. performed the ex situ and operando XAS measurements and analysed the data. L.L. performed HR-STEM, HR-TEM and EELS on the Cu-X catalysts and discussed the results with H.W., and D.V. and S.Y. performed DFT data collections and discussed the results with H.W. E.P. carried out the liquid NMR spectroscopy measurements. K.Q. and Y.Z. assisted H.W. with the electrochemical investigations and the gas chromatography analyses. W.W., J. Li and J. Liu assisted H.W. with the physical characterization of the samples and the operando Raman measurements. C.S. and P.M. discussed the electrocatalytic performance with H.W. and D.V. B.R.C. discussed the XAS data with J.T., H.W. and D.V. All authors discussed the results and assisted during manuscript preparation.
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Wu, H., Huang, L., Timoshenko, J. et al. Selective and energy-efficient electrosynthesis of ethylene from CO2 by tuning the valence of Cu catalysts through aryl diazonium functionalization. Nat Energy 9, 422–433 (2024). https://doi.org/10.1038/s41560-024-01461-6
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DOI: https://doi.org/10.1038/s41560-024-01461-6
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