Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Perspective
  • Published:

The why and how of NOx electroreduction to ammonia


Electroreduction of the oxidized forms of nitrogen (NOx) has been studied for decades, with the most recent intense research focusing on the conversion of nitrate to ammonia. Here we discuss how such technology might, or might not, be able to contribute to sustainable ammonia (NH3) production and highlight its conceptual and experimental differences from the electrosynthesis of NH3 from dinitrogen. A generic experimental protocol for NOx-to-NH3 studies is proposed and discussed along with the situations where control experiments with a 15N-labelled nitrogen source may not be required.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Possible pathways for the sustainable electrosynthesis of NH3.
Fig. 2: Nitrate-to-NH3/ammonium reports.
Fig. 3: Simplified protocol for NOx-to-NH3 studies.

Similar content being viewed by others


  1. Choi, J. et al. Identification and elimination of false positives in electrochemical nitrogen reduction studies. Nat. Commun. 11, 5546 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  2. Tanaka, H. et al. Unique behaviour of dinitrogen-bridged dimolybdenum complexes bearing pincer ligand towards catalytic formation of ammonia. Nat. Commun. 5, 3737 (2014).

    Article  PubMed  Google Scholar 

  3. Fichter, F., Girard, P. & Erlenmeyer, H. Elektrolytische Bindung von komprimiertem Stickstoff bei gewöhnlicher Temperatur. HCA 13, 1228–1236 (1930).

    Article  CAS  Google Scholar 

  4. Lazouski, N., Chung, M., Williams, K., Gala, M. L. & Manthiram, K. Non-aqueous gas diffusion electrodes for rapid ammonia synthesis from nitrogen and water-splitting-derived hydrogen. Nat. Catal. 3, 463–469 (2020).

    Article  CAS  Google Scholar 

  5. Du, H. L. et al. Electroreduction of nitrogen with almost 100% current-to-ammonia efficiency. Nature 609, 722–727 (2022).

    Article  CAS  PubMed  Google Scholar 

  6. Fu, X. et al. Continuous-flow electrosynthesis of ammonia by nitrogen reduction and hydrogen oxidation. Science 379, 707–712 (2023).

    Article  CAS  PubMed  Google Scholar 

  7. van Langevelde, P. H., Katsounaros, I. & Koper, M. T. M. Electrocatalytic nitrate reduction for sustainable ammonia production. Joule 5, 290–294 (2021).

    Article  Google Scholar 

  8. Theerthagiri, J. et al. Electrocatalytic conversion of nitrate waste into ammonia: a review. Environ. Chem. Lett. 20, 2929–2949 (2022).

    Article  CAS  Google Scholar 

  9. MacFarlane, D. R. et al. A roadmap to the ammonia economy. Joule 4, 1186–1205 (2020).

    Article  CAS  Google Scholar 

  10. International Energy Agency. Ammonia Technology Roadmap: Towards more Sustainable Nitrogen Fertiliser Production (IEA, 2021);

  11. International Renewable Energy Agency. Innovation Outlook: Renewable Ammonia (IRENA, 2022);

  12. MacFarlane, D., Simonov, A. N., Vu, T., Johnston, S. & Azofra, L. M. Sustainable nitrogen activation—are we there yet? Faraday Discuss. 243, 557–570 (2023).

    Article  CAS  PubMed  Google Scholar 

  13. Hager, T. The Alchemy of Air: a Jewish Genius, a Doomed Tycoon, and the Scientific Discovery that Fed the World but Fueled the Rise of Hitler (Harmony Books, 2008).

  14. Alves, L. et al. A comprehensive review of NOx and N2O mitigation from industrial streams. Renew. Sustain. Energy Rev. 155, 111916 (2022).

    Article  CAS  Google Scholar 

  15. Ergas, S. J. & Aponte-Morales, V. in Comprehensive Water Quality and Purification, Vol. 3 (ed. Ahuja, S.) 123–149 (Elsevier, 2014).

  16. International Atomic Energy Agency. Status and Trends in Spent Fuel and Radioactive Waste Management (IAEA, 2022).

  17. US Nuclear Regulatory Commission. Low-Level Waste Disposal Statistics (NRC, 2023);

  18. Anner, N. Upgrading Your Fleet for Future Fuels (MAN Energy Solutions, 2022);

  19. International Energy Agency. World Energy Outlook 2022 (IEA, 2022);

  20. Lide, D. R. CRC Handbook of Chemistry and Physics, 84th edn (CRC Press, 2004).

  21. Smith, C., Hill, A. K. & Torrente-Murciano, L. Current and future role of Haber-Bosch ammonia in a carbon-free energy landscape. Energy Environ. Sci. 13, 331–344 (2020).

    Article  Google Scholar 

  22. Jupiter Ionics. Global Leaders in Green Ammonia (Jupiter Ionics, 2021);

  23. Chen, J. G. et al. Beyond fossil fuel-driven nitrogen transformations. Science 360, eaar6611 (2018).

    Article  PubMed  PubMed Central  Google Scholar 

  24. Sugiyama, K. et al. Ammonia synthesis by means of plasma over MgO catalyst. Plasma Chem. Plasma Process. 6, 179–193 (1986).

    Article  CAS  Google Scholar 

  25. Sun, J. et al. A hybrid plasma electrocatalytic process for sustainable ammonia production. Energy Environ. Sci. 14, 865–872 (2021).

    Article  CAS  Google Scholar 

  26. PlasmaLeap;

  27. Muzammil, I. et al. Plasma catalyst-integrated system for ammonia production from H2O and N2 at atmospheric pressure. ACS Energy Lett. 6, 3004–3010 (2021).

    Article  CAS  Google Scholar 

  28. Wu, A. et al. Direct ammonia synthesis from the air via gliding arc plasma integrated with single atom electrocatalysis. Appl. Catal. B 299, 120667 (2021).

    Article  CAS  Google Scholar 

  29. Plieth, W. J. in Encyclopedia of Electrochemistry of the Elements (eds. Bard, A, J. & Lund, H.) Ch. VIII-5, 321–479 (Dekker, 1978).

  30. Rosca, V., Duca, M., de Groot, M. T. & Koper, M. T. M. Nitrogen cycle electrocatalysis. Chem. Rev. 109, 2209–2244 (2009).

    Article  CAS  PubMed  Google Scholar 

  31. Mattarozzi, L. et al. Electrochemical reduction of nitrate and nitrite in alkaline media at CuNi alloy electrodes. Electrochim. Acta 89, 488–496 (2013).

    Article  CAS  Google Scholar 

  32. Bui, T. S., Lovell, E. C., Daiyan, R. & Amal, R. Defective metal oxides: lessons from CO2RR and applications in NOxRR. Adv. Mater. 35, 2205814 (2023).

    Article  CAS  Google Scholar 

  33. Han, S. et al. Ultralow overpotential nitrate reduction to ammonia via a three-step relay mechanism. Nat. Catal. 6, 402–414 (2023).

    Article  CAS  Google Scholar 

  34. Andersen, S. Z. et al. A rigorous electrochemical ammonia synthesis protocol with quantitative isotope measurements. Nature 570, 504–508 (2019).

    Article  CAS  PubMed  Google Scholar 

  35. Hodgetts, R. Y. et al. Refining universal procedures for ammonium quantification via rapid 1H NMR analysis for dinitrogen reduction studies. ACS Energy Lett. 5, 736–741 (2020).

    Article  CAS  Google Scholar 

  36. Aouina, N., Cachet, H., Debiemme-chouvy, C. & Tran, T. T. M. Insight into the electroreduction of nitrate ions at a copper electrode, in neutral solution, after determination of their diffusion coefficient by electrochemical impedance spectroscopy. Electrochim. Acta 55, 7341–7345 (2010).

    Article  CAS  Google Scholar 

Download references


We are grateful to the Australian Research Council for financial support (project no. DP200101878 and Future Fellowship FT200100317 to A.N.S.).

Author information

Authors and Affiliations



All authors contributed to the preparation and writing of the manuscript.

Corresponding authors

Correspondence to Douglas R. MacFarlane or Alexandr N. Simonov.

Ethics declarations

Competing interests

D.R.M. and A.N.S. have minority equity ownership, as well as management and consulting roles, in a spin-out company, Jupiter Ionics Pty Ltd, that is scaling up the Li-mediated NH3 electrosynthesis technology.

Peer review

Peer review information

Nature Catalysis thanks the anonymous reviewers for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

John, J., MacFarlane, D.R. & Simonov, A.N. The why and how of NOx electroreduction to ammonia. Nat Catal 6, 1125–1130 (2023).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing