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Ampere-level electrosynthesis of a nylon-6 precursor by local NO coverage tuning

Nature Synthesis volume 4, pages 1504–1512 (2025)Cite this article

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Abstract

Cyclohexanone oxime (CHO) electrosynthesis from NO and cyclohexanone with high Faradaic efficiency at ampere-level current density is desirable but challenging. Here theoretical calculations reveal that NO coverage on silver catalysts plays a critical role in CHO electrosynthesis. We then experimentally adjust the NO coverage by tuning the bulk NO concentration and reaction rate. We find that low NO coverage benefits NH3 formation, whereas high coverage delivers CHO and N2. Mechanistic studies indicate that with increasing NO coverage, active sites transfer from bridge step to hollow terrace sites at which NH2OH* can stably exist, rather than its decomposition into NH3. However, N‒N coupling also readily occurs at high NO coverage. This understanding inspires us to develop a doping strategy to inhibit NO–NO coupling at high NO coverage. A ruthenium-doped silver catalyst is therefore developed, realizing 86% CHO Faradaic efficiency at 1.0 A cm−2, far exceeding previously reported performance.

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Fig. 1: Reaction process diagram and catalyst screening for CHO electrosynthesis.
Fig. 2: DFT calculation results for the effects of NO coverage.
Fig. 3: CHO electrosynthesis performance as a function of NO coverage.
Fig. 4: Investigation of the reaction mechanism under low and high NO coverages.
Fig. 5: Calculated and experimental results of AgRu for CHO electrosynthesis.
Fig. 6: Synthesis and characterization of [15N]pralidoxime.

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Data availability

The DFT-optimized atomic coordinates are available via Zenodo at https://zenodo.org/records/15590189 (ref. 45). The data that support the findings of this study are available in the paper and its Supplementary Information. Source data are provided with this paper.

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Acknowledgements

We acknowledge the National Natural Science Foundation of China (22401212 to Y.W., 22271213 to B.Z. and 224B2306 to R.Y.).

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  1. These authors contributed equally: Yongmeng Wu, Xinyu Liu, Rong Yang.

Authors and Affiliations

  1. Department of Chemistry, School of Science, Tianjin University, Tianjin, China

    Yongmeng Wu, Xinyu Liu, Rong Yang, Chuanqi Cheng, Ziyang Song & Bin Zhang

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Contributions

B.Z. conceived the idea and directed the project. Y.W. and B.Z. designed the experiments. X.L. and Y.W. carried out the experiments. R.Y. and C.C. performed the DFT calculations. Z.S. assisted with some experiments. X.L., Y.W. and B.Z. analysed the data. Y.W. wrote the paper. B.Z. revised the paper. All the authors discussed the results and commented on the paper.

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Correspondence to Bin Zhang.

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Nature Synthesis thanks Jeong Woo Han and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editor: Alexandra Groves, in collaboration with the Nature Synthesis team.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–55, Notes 1–19, Tables 1–8 and References 1–18.

Supplementary Data 1

Calculational models for Ag and AgRu.

Source data

Source Data Fig. 1

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Source Data Fig. 2

The source data underlying Fig. 2.

Source Data Fig. 3

The source data underlying Fig. 3.

Source Data Fig. 4

The source data underlying Fig. 4.

Source Data Fig. 5

The source data underlying Fig. 5.

Source Data Fig. 6

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Wu, Y., Liu, X., Yang, R. et al. Ampere-level electrosynthesis of a nylon-6 precursor by local NO coverage tuning. Nat. Synth 4, 1504–1512 (2025). https://doi.org/10.1038/s44160-025-00851-2

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