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.

Pivotal role of reversible NiO6 geometric conversion in oxygen evolution



Realizing an efficient electron transfer process in the oxygen evolution reaction by modifying the electronic states around the Fermi level is crucial in developing high-performing and robust electrocatalysts1,2,3. Typically, electron transfer proceeds solely through either a metal redox chemistry (an adsorbate evolution mechanism (AEM), with metal bands around the Fermi level) or an oxygen redox chemistry (a lattice oxygen oxidation mechanism (LOM), with oxygen bands around the Fermi level), without the concurrent occurrence of both metal and oxygen redox chemistries in the same electron transfer pathway1,2,3,4,5,6,7,8,9,10,11,12,13,14,15. Here we report an electron transfer mechanism that involves a switchable metal and oxygen redox chemistry in nickel-oxyhydroxide-based materials with light as the trigger. In contrast to the traditional AEM and LOM, the proposed light-triggered coupled oxygen evolution mechanism requires the unit cell to undergo reversible geometric conversion between octahedron (NiO6) and square planar (NiO4) to achieve electronic states (around the Fermi level) with alternative metal and oxygen characters throughout the oxygen evolution process. Utilizing this electron transfer pathway can bypass the potential limiting steps, that is, oxygen–oxygen bonding in AEM and deprotonation in LOM1,2,3,4,5,8. As a result, the electrocatalysts that operate through this route show superior activity compared with previously reported electrocatalysts. Thus, it is expected that the proposed light-triggered coupled oxygen evolution mechanism adds a layer of understanding to the oxygen evolution research scene.

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

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Schematic illustration of OER routes.
Fig. 2: OER activities of traditional NiOOH and NR-NiOOH with and without light irradiation.
Fig. 3: Identification of redox activities for NR-NiOOH subjected to light irradiation.
Fig. 4: Proposed light-induced electron transfer process with switchable metal and oxygen redox centres for the OER.
Fig. 5: The origins of our proposed coupled evolution mechanism.

Data availability

The authors declare that all data supporting of the finding of this study are included within the paper and its Supplementary Information files and are available from the corresponding authors on request.


  1. Grimaud, A., Hong, W. T., Shao-Horn, Y. & Tarascon, J. M. Anionic redox progresses for electrochemical devices. Nat. Mater. 15, 121–126 (2016).

    Article  CAS  PubMed  ADS  Google Scholar 

  2. Huang, Z. F. et al. Chemical and structural origin of lattice oxygen oxidation in Co–Zn oxyhydroxide oxygen evolution electrocatalysts. Nat. Ener. 4, 329–338 (2019).

    Article  CAS  ADS  Google Scholar 

  3. Song, J. et al. A review on fundamental for designing oxygen evolution electrocatalysts. Chem. Soc. Rev. 49, 2196 (2020).

    Article  CAS  PubMed  Google Scholar 

  4. Grimaud, A. et al. Activating lattice oxygen redox reaction in metal oxides to catalyse oxygen evolution. Nat. Chem. 9, 457–465 (2017).

    Article  CAS  PubMed  Google Scholar 

  5. Mefford, J. T. et al. Water electrolysis on La1−xSrxCoO3δ perovskite electrocatalysts. Nat. Commun. 7, 11503 (2017).

    Google Scholar 

  6. Pan, Y. et al. Direct evidence of boosted oxygen evolution over perovskite by enhanced lattice oxygen participation. Nat. Commun. 11, 2002 (2020).

    Article  CAS  PubMed  PubMed Central  ADS  Google Scholar 

  7. Hibbert, D. B. & Churchill, C. R. Kinetics of the electrochemical evolution of isotopically enriched gases part 2.—18O16O evolution on NiCo2O4 and LixCo3xO4 in alkaline solution. J. Chem. Soc. Faraday Trans. 80, 1965–1975 (1984).

    Article  CAS  Google Scholar 

  8. Wang, X. et al. Strain stabilized nickel hydroxide nanoribbons for efficient water splitting. Energy Environ. Sci. 13, 229–237 (2020).

    Article  CAS  Google Scholar 

  9. Nong, H. N. et al. Key role of chemistry versus bias in electrocatalytic oxygen evolution. Nature 587, 408–413 (2020).

    Article  CAS  PubMed  ADS  Google Scholar 

  10. Rao, R. et al. Towards identifying the active sites on RuO2 (110) in catalyzing oxygen evolution. Energy Environ. Sci. 10, 2626–2637 (2017).

  11. Halck, N., Petrykin, V., Krtil, P. & Rossmeisl, J. Beyond the volcano limitations in electrocatalysis-oxygen evolution reaction. Phys. Chem. Chem. Phys. 16, 13682–13688 (2014).

    Article  CAS  PubMed  Google Scholar 

  12. Craig, M. et al. Universal scaling relations for the rational design of molecular water oxidation catalysts with near-zero overpotential. Nat. Commun. 10, 4993 (2019).

    Article  PubMed  PubMed Central  ADS  Google Scholar 

  13. Retuerto, M. et al. Role of lattice oxygen content and Ni geometry in the oxygen evolution activity of the Ba-Ni-O system. J. Power Sources 404, 56–63 (2018).

    Article  CAS  ADS  Google Scholar 

  14. Garces-Pineda, F., Blasco-Ahicart, M., Nieto-Castro, D., Lopez, N. & Galan-Mascaros, J. Direct magnetic enhancement of electrocatalytic water oxidation in alkaline media. Nat. Energy 4, 519–525 (2019).

    Article  CAS  ADS  Google Scholar 

  15. Gracia, J. Spin dependent interactions catalyse the oxygen electrochemistry. Phys. Chem. Chem. Phys. 19, 20451–20456 (2017).

    Article  CAS  PubMed  Google Scholar 

  16. Wang, X. et al. Materializing efficient methanol oxidation via electron delocalization in nickel hydroxide nanoribbon. Nat. Commun. 11, 4647 (2020).

    Article  CAS  PubMed  PubMed Central  ADS  Google Scholar 

  17. Colburn, A. W., Levey, K. J., Ohare, D. & Macpherson, J. V. Lifting the lid on the potentiostat: a beginner’s guide to understanding electrochemical circuitry and practical operation. Phys. Chem. Chem. Phys. 23, 8100–8117 (2021).

    Article  CAS  PubMed  Google Scholar 

  18. Dionigi, F. & Strasser, P. NiFe-based (oxy)hydroxide catalysts for oxygen evolution reaction in non-acidic electrolytes. Adv. Energy Mater. 6, 1600621 (2016).

    Article  Google Scholar 

  19. Wei, C. et al. Recommended practices and benchmark activity for hydrogen and oxygen electrocatalysis in water splitting and fuel cells. Adv. Mater. 31, 1806296 (2019).

    Article  Google Scholar 

  20. Morales, D. M. & Risch, M. Seven steps to reliable cyclic voltammetry measurements for the determination of double layer capacitance. J. Phys. Energy 3, 034013 (2021).

    Article  CAS  ADS  Google Scholar 

  21. Formal, F. et al. Back electron-hole recombination in hematite photoanodes for water splitting. J. Am. Chem. Soc. 136, 2564–2574 (2014).

    Article  PubMed  Google Scholar 

  22. Krysiak, O., Cichowicz, G., Conzuelo, F., Cyranski, M. & Augustynski, J. Ni–Fe–Cr-oxides: an efficient catalyst activated by visible light for the oxygen evolution reaction. Z. Phys. Chem. 234, 633–643 (2020).

    Article  CAS  Google Scholar 

  23. Suntivich, J., May, K. J., Gasteiger, H. A., Goodenough, J. B. & Shao-Horn, Y. A perovskite oxide optimized for oxygen evolution catalysis from molecular orbital principles. Science 334, 1383–1385 (2011).

    Article  CAS  PubMed  ADS  Google Scholar 

  24. Bediako, D. K. et al. Structure activity correlations in a nickel-borate oxygen evolution catalyst. J. Am. Chem. Soc. 134, 6801–6809 (2012).

    Article  CAS  PubMed  Google Scholar 

  25. McBreen, J. et al. In situ time-resolved X-ray absorption near edge structure study of the nickel oxide electrode. J. Phys. Chem. 93, 6308–6311 (1989).

    Article  CAS  Google Scholar 

  26. Friebel, D. et al. Identification of highly active Fe sites in (Ni,Fe)OOH for electrocatalytic water splitting. J. Am. Chem. Soc. 137, 1305–1313 (2015).

    Article  CAS  PubMed  Google Scholar 

  27. Ohtsu, H. & Tanaka, K. Equilibrium of low- and high-spin states of Ni(II) complexes controlled by the donor ability of bidentate ligands. Inorg. Chem. 43, 3024–3030 (2004).

    Article  CAS  PubMed  Google Scholar 

  28. Nast, R. Coordination chemistry of metal alkynyl compounds. Coord. Chem. Rev. 47, 125–164 (1982).

    Article  Google Scholar 

  29. Tao, Z. et al. The nature of photoinduced phase transition and metastable states in vanadium dioxide. Sci. Rep. 6, 38514 (2016).

    Article  CAS  PubMed  PubMed Central  ADS  Google Scholar 

  30. Yang, C., Fontaine, O., Tarascon, J. & Grimaud, A. Chemical recognition of active oxygen species on the surface of oxygen evolution reaction electrocatalysts. Angew. Chem. Int. Edn 129, 8778–8782 (2017).

    Article  ADS  Google Scholar 

  31. Nitopi, S. et al. Progress and perspectives of electrochemical CO2 reduction on copper in aqueous electrolyte. Chem. Rev. 119, 7610–7672 (2019).

    Article  CAS  PubMed  Google Scholar 

  32. Köhler, L., Abrishami, M., Raddatis, V., Geppert, J. & Risch, M. Mechanistic parameters of electrocatalytic water oxidation on LiMn2O4 in comparison to natural photosynthesis. ChemSusChem 10, 4479–4490 (2017).

    Article  PubMed  PubMed Central  Google Scholar 

  33. Zhang, Q. & Asthagiri, A. Solvation effects on DFT predictions of ORR activity on metal surfaces. Catal. Today 323, 35–43 (2019).

    Article  CAS  Google Scholar 

  34. Trzesniewski, B. J. et al. In situ observation of active oxygen species in Fe-containing Ni-based oxygen evolution catalysts: the effect of pH on electrochemical activity. J. Am. Chem. Soc. 137, 15112–15121 (2015).

    Article  CAS  PubMed  Google Scholar 

  35. Hao, Y. et al. Recognition of surface oxygen intermediates on NiFe oxyhydroxide oxygen-evolving catalysts by homogeneous oxidation reactivity. J. Am. Chem. Soc. 143, 1493–1502 (2021).

    Article  CAS  PubMed  Google Scholar 

  36. Roy, C. et al. Impact of nanoparticles size and lattice oxygen on water oxidation on NiFeOxHy. Nat. Catal. 1, 820–829 (2018).

    Article  CAS  Google Scholar 

  37. Zhang, F. et al. Decoupled redox catalytic hydrogen production with a robust electrolyte-Borne electron and proton carrier. J. Am. Chem. Soc. 143, 223–231 (2021).

    Article  CAS  PubMed  Google Scholar 

Download references


We thank H. Wang and C. Wang for their help with figure design and A. Stefan for his advice on simulation. This work is financially supported by Singapore Ministry of Education (MOE) Tier 1 R284000226114 and MOE Tier 2 (MOE2018-T2-1-149), Agency for Science, Technology and Research (A*STAR) of Singapore. This research is also supported by A*STAR, grant number 152-70-00017, and computational resources were provided by National Supercomputing Centre Singapore (NSCC) and A*STAR Computational Resource Centre, Singapore (A*CRC). This project was partly supported by the Science and Engineering Research Council (SERC) of A*STAR of Singapore. This research is also supported by the Guangxi Bagui Scholar Foundation, Guilin Lijiang Scholar Foundation, Science and Technology Development Project of Guilin (20210216-1).

Author information

Authors and Affiliations



X.W., S.X. and J.X. conceived the idea. X.W. and W.S.V.L. performed synthesis and electrochemical measurement of the samples. X.W., W.S.V.L., H.Z., Q.W., H.W. and Z.W. were responsible for the analysis of electrochemical results. S.X., Y.D. and A.B. were responsible for the XAFS characterization. Z.G.Y., P.H. and Y.-W.Z. carried out DFT simulations. J.X. is in charge of the overall project and preparation of the manuscript.

Corresponding authors

Correspondence to Shibo Xi, Hao Wang, Zhi Gen Yu, Wee Siang Vincent Lee or Junmin Xue.

Ethics declarations

Competing interests

The authors declare no competing interests.

Peer review

Peer review information

Nature thanks Marcel Risch and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

Additional information

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

Supplementary information

Supplementary Information

This file contains Supplementary Materials and Methods, Discussion, Figs. 1–41, Tables 1–6 and References.

Peer Review File

Rights and permissions

Springer Nature or its licensor 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

Verify currency and authenticity via CrossMark

Cite this article

Wang, X., Xi, S., Huang, P. et al. Pivotal role of reversible NiO6 geometric conversion in oxygen evolution. Nature 611, 702–708 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


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