Skip to main content

Thank you for visiting nature.com. 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.

  • Article
  • Published:

Ruthenium-catalysed oxidative conversion of ammonia into dinitrogen

An Author Correction to this article was published on 26 February 2020

This article has been updated

Abstract

Conversion of ammonia into dinitrogen has attracted broad scientific interest in relation to molecular models of the heterogeneous nitrogen fixation process, environmental treatment for denitrification and utilization of ammonia as an energy carrier. Here we show that some ruthenium complexes bearing 2,2′-bipyridyl-6,6′-dicarboxylate ligands work as catalysts for the ammonia oxidation reaction. Production of dinitrogen is observed when ammonium salts are treated with a triarylaminium radical as an oxidant and 2,4,6-collidine as a base in the presence of the ruthenium catalysts. Based on the characterization of some intermediates, we propose a reaction pathway via a bimetallic nitride–nitride coupling process. The proposed reaction pathway is supported by density functional theory calculations. Further investigation of the ammonia oxidation reaction under the electrochemical conditions revealed that the ruthenium complex works as a new anode catalyst for ammonia oxidation.

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: Catalytic reactions to convert ammonia into N2.
Fig. 2: Transformations of ruthenium complexes 1a and 1b.
Fig. 3: DFT calculations.
Fig. 4: Electrochemical analysis.

Similar content being viewed by others

Data availability

Crystallographic data for the structure reported in this Article have been deposited at the Cambridge Crystallographic Data Centre, under deposition nos. CCDC 1860066 (6a), 1860067 (6b), 1860068 (7), 1860069 (8) and 1860070 (9) (Supplementary Table 5). All other data supporting the findings of this study are available within the Article and its Supplementary Information, or from the corresponding author upon reasonable request.

Change history

  • 26 February 2020

    An amendment to this paper has been published and can be accessed via a link at the top of the paper.

References

  1. Guo, J. & Chen, P. Catalyst: NH3 as an energy carrier. Chem. 3, 709–712 (2017).

    Article  CAS  Google Scholar 

  2. Giddy, S., Badwal, S. P. S., Munnings, C. & Dolan, M. Ammonia as a renewable energy transportation media. ACS Sustain. Chem. Eng. 5, 10231–10239 (2017).

    Article  Google Scholar 

  3. Lan, R., Irvine, J. T. S. & Tao, S. Ammonia and related chemicals as potential indirect hydrogen storage materials. Int. J. Hydrogen Energy 37, 1482–1494 (2012).

    Article  CAS  Google Scholar 

  4. Adli, N. M., Zhang, H., Mukherjee, S. & Wu, G. Review—ammonia oxidation electrocatalysis for hydrogen generation and fuel cells. J. Electrochem. Soc. 165, J3130–J3147 (2018).

    Article  CAS  Google Scholar 

  5. Mukherjee, S. et al. Low-temperature ammonia decomposition catalysts for hydrogen generation. Appl. Catal. B Environ. 226, 162–181 (2018).

    Article  CAS  Google Scholar 

  6. Zhong, C., Hu, W. B. & Cheng, Y. F. Recent advances in electrocatalysts for electro-oxidation of ammonia. J. Mater. Chem. A 1, 3216–3238 (2013).

    Article  CAS  Google Scholar 

  7. Habibzadeh, F., Miller, S. L., Hamann, T. W. & Smith, M. R. III Homogeneous electrocatalytic oxidation of ammonia to N2 under mild conditions. Proc. Natl Acad. Sci. USA 116, 2849–2853 (2019).

    Article  CAS  Google Scholar 

  8. Pipes, D. W. et al. Reversible interconversion between a nitrido complex of Os(vi) and an ammino complex of osmium(ii). J. Am. Chem. Soc. 112, 5507–5514 (1990).

    Article  CAS  Google Scholar 

  9. Ishitani, O., White, P. S. & Meyer, T. J. Formation of dinitrogen by oxidation of [(bpy)2(NH3)RuORu(NH3)(bpy)2]4+. Inorg. Chem. 35, 2167–2168 (1996).

    Article  CAS  Google Scholar 

  10. Ishitani, O., Ando, E. & Meyer, T. J. Dinitrogen formation by oxidative intramolecular N–N coupling in cis,cis-[(bpy)2(NH3)RuORu(NH3)(bpy)2]4+. Inorg. Chem. 42, 1707–1710 (2003).

    Article  CAS  Google Scholar 

  11. Bezdek, M. J., Guo, S. & Chirik, P. J. Coordination-induced weakening of ammonia, water, and hydrazine X–H bonds in a molybdenum complex. Science 354, 730–733 (2016).

    Article  CAS  Google Scholar 

  12. Margulieux, G. W., Bezdek, M. J., Turner, Z. R. & Chirik, P. J. Ammonia activation, H2 evolution and nitride formation from a molybdenum complex with a chemically and redox noninnocent ligand. J. Am. Chem. Soc. 139, 6110–6113 (2017).

    Article  CAS  Google Scholar 

  13. Bhattacharya, P. et al. Ammonia oxidation by abstraction of three hydrogen atoms from a Mo–NH3 complex. J. Am. Chem. Soc. 139, 2916–2919 (2017).

    Article  CAS  Google Scholar 

  14. Man, W.-L., Lam, W. W. Y. & Lau, T.-C. Reactivity of nitrido complexes of ruthenium(vi), osmium(vi) and manganese(v) bearing Schiff base and simple anionic ligands. Acc. Chem. Res. 47, 427–439 (2014).

    Article  CAS  Google Scholar 

  15. Berry, J. F. Terminal nitrido and imido complexes of the late transition metals. Comments Inorg. Chem. 30, 28–66 (2009).

    Article  CAS  Google Scholar 

  16. Man, W.-L. et al. Highly electrophilic (salen)ruthenium(vi) nitrido complexes. J. Am. Chem. Soc. 126, 478–479 (2004).

    Article  CAS  Google Scholar 

  17. Betley, T. A. & Peters, J. C. A tetrahedrally coordinated L3Fe-Nx platform that accommodates terminal nitride (FeIV≡N) and dinitrogen (FeI–N2–FeI) ligands. J. Am. Chem. Soc. 126, 6252–6254 (2004).

    Article  CAS  Google Scholar 

  18. Scheibel, M. G. et al. Closed-shell and open-shell square-planar iridium nitrido complexes. Nat. Chem. 4, 552–558 (2012).

    Article  CAS  Google Scholar 

  19. Miyazaki, T. et al. Cleavage and formation of molecular dinitrogen in a single system assisted by molybdenum complexes bearing ferrocenyldiphosphine. Angew. Chem. Int. Ed. 53, 11488–11492 (2014).

    Article  CAS  Google Scholar 

  20. Clarke, R. M. & Storr, T. Tuning electronic structure to control manganese nitride activation. J. Am. Chem. Soc. 138, 15299–15302 (2016).

    Article  CAS  Google Scholar 

  21. Keener, M. et al. Towards catalytic ammonia oxidation to dinitrogen: a synthetic cycle by using a simple manganese complex. Chem. Eur. J. 23, 11479–11484 (2017).

    Article  CAS  Google Scholar 

  22. Duan, L. et al. A molecular ruthenium catalyst with water-oxidation activity comparable to that of photosystem II. Nat. Chem. 4, 418–423 (2012).

    Article  CAS  Google Scholar 

  23. Gersten, S. W., Samuels, G. J. & Meyer, T. J. Catalytic oxidation of water by an oxo-bridged ruthenium dimer. J. Am. Chem. Soc. 104, 4029–4030 (1982).

    Article  CAS  Google Scholar 

  24. Tseng, H.-W., Zong, R., Muckerman, J. T. & Thummel, R. Mononuclear ruthenium(ii) complexes that catalyze water oxidation. Inorg. Chem. 47, 11763–11773 (2008).

    Article  CAS  Google Scholar 

  25. Masaoka, S. & Sakai, K. Clear evidence showing the robustness of a highly active oxygen-evolving mononuclear ruthenium complex with an aqua ligand. Chem. Lett. 38, 182–183 (2009).

    Article  CAS  Google Scholar 

  26. Zhang, B. et al. Characterization of a trinuclear ruthenium species in catalytic water oxidation by Ru(bda)(pic)2 in neutral media. Chem. Commun. 52, 8619–8622 (2016).

    Article  CAS  Google Scholar 

  27. Duan, L., Fischer, A., Xu, Y. & Sun, L. Isolated seven-coordinate Ru(iv) dimer complex with [HOHOH] bridging ligand as an intermediate for catalytic water oxidation. J. Am. Chem. Soc. 131, 10397–10399 (2009).

    Article  CAS  Google Scholar 

  28. MacKay, B. A. & Fryzuk, M. D. Dinitrogen coordination chemistry: on the biomimetic borderlands. Chem. Rev. 104, 385–402 (2004).

    Article  CAS  Google Scholar 

  29. Huynh, M. H. V. & Meyer, T. J. Proton-coupled electron transfer. Chem. Rev. 107, 5004–5064 (2007).

    Article  CAS  Google Scholar 

  30. Waidmann, C. R. et al. Using combinations of oxidants and bases as PCET reactants: thermochemical and practical considerations. Energy Environ. Sci. 5, 7771–7780 (2012).

    Article  CAS  Google Scholar 

  31. Becke, A. D. Density‐functional thermochemistry. III. The role of exact exchange. J. Chem. Phys. 98, 5648–5652 (1993).

    Article  CAS  Google Scholar 

  32. Lee, C., Yang, W. & Parr, R. G. Development of the Colle–Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B 37, 785–789 (1988).

    Article  CAS  Google Scholar 

  33. Stephens, P. J., Devlin, F. J., Chabalowski, C. F. & Frisch, M. J. Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields. J. Phys. Chem. 98, 11623–11627 (1994).

    Article  CAS  Google Scholar 

  34. Grimme, S., Antony, J., Ehrlich, S. & Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H–Pu. J. Chem. Phys. 132, 154104 (2010).

    Article  Google Scholar 

  35. Coia, G. M. et al. Osmium hydrazido and dinitrogen complexes. Inorg. Chem. 36, 2341–2351 (1997).

    Article  CAS  Google Scholar 

  36. Lindley, B. M. et al. Evaluating the thermodynamics of electrocatalytic N2 reduction in acetonitrile. ACS Energy Lett. 1, 698–704 (2016).

    Article  CAS  Google Scholar 

  37. Pavlishchuk, V. V. & Addison, A. W. Conversion constants for redox potentials measured versus different reference electrodes in acetonitrile solutions at 25 °C. Inorg. Chim. Acta 298, 97–102 (2000).

    Article  CAS  Google Scholar 

  38. Nicholson, R. S. & Shain, I. Theory of stationary electrode polarography. Single scan and cyclic methods applied to reversible, irreversible, and kinetic systems. Anal. Chem. 36, 706–723 (1964).

    Article  CAS  Google Scholar 

  39. Rees, N. V. & Compton, R. G. Carbon-free energy: a review of ammonia- and hydrazine-based electrochemical fuel cells. Energy Environ. Sci. 4, 1255–1260 (2011).

    Article  CAS  Google Scholar 

  40. Ertl, G. Reactions at surfaces: from atoms to complexity (Nobel lecture). Angew. Chem. Int. Ed. 47, 3524–3535 (2008).

    Article  CAS  Google Scholar 

  41. Du, R. et al. Advanced nitrogen removal from wastewater by combining anammox with partial denitrification. Bioresour. Technol. 179, 497–504 (2015).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

This work was supported by CREST, JST (JPMJCR1541). The authors acknowledge support from JSPS KAKENHI grants nos. JP15H05798, JP17H01201, JP18K19093 and JP19K15556 from the Japan Society for the Promotion of Science (JSPS) and the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT). We also thank J. C. Peters and S. Schneider for helpful discussions.

Author information

Authors and Affiliations

Authors

Contributions

K.S. and Y.N. directed and conceived this project. K.N. and H.T. conducted the experimental work. K.S. conducted the computational work. All authors discussed the results and wrote the manuscript.

Corresponding authors

Correspondence to Ken Sakata or Yoshiaki Nishibayashi.

Ethics declarations

Competing interests

K.N., H.T. and Y.N. have filed a patent based on the work described here (Japanese patent application no. 2018-036966).

Additional information

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

Supplementary information

Supplementary Information

Experimental procedures; products characterization; X-ray crystallographic analysis; kinetic, electrochemical and DFT studies.

6a-CH4O.cif

Crystallographic Information File for compounds 6a, CCDC 1860066

6b-2CH4O.cif

Crystallographic Information File for compounds 6b, CCDC 1860067

7-H2O.cif

Crystallographic Information File for compounds 7, CCDC 1860068

8.cif

Crystallographic Information File for compounds 8, CCDC 1860069

9.cif

Crystallographic Information File for compounds 9, CCDC 1860070

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Nakajima, K., Toda, H., Sakata, K. et al. Ruthenium-catalysed oxidative conversion of ammonia into dinitrogen. Nat. Chem. 11, 702–709 (2019). https://doi.org/10.1038/s41557-019-0293-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41557-019-0293-y

This article is cited by

Search

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