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Spin crossover-driven diiron electrocatalyst boosts sustainable water oxidation

Nature Sustainability volume 8, pages 793–805 (2025)Cite this article

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Abstract

Electrocatalytic reduction of carbon dioxide and water oxidation are promising technologies to mitigate environmental problems. A critical bottleneck, however, is the significant energy loss that arises from the anodic oxygen evolution reaction (OER) with its sluggish kinetics and reliance on scarce noble metals. It is therefore essential to develop earth-abundant and efficient OER catalysts. Here we report the reactive diiron electrocatalyst [Fe2(µ-O)(µ-OH)(L1)2], where L1 is a nitrogen-based ligand, which exhibits an outstanding performance—achieving a turnover frequency of 20.2 s−1 at 1.580 V and a low overpotential of 184 mV at a current density of 10 mA cm−2—and exceptional stability over 1,000 h. This diiron electrocatalyst is formed via a spin crossover-driven dimerization mechanism, where the resulting diiron atomic configuration promotes strong metal–ligand covalency and facilitates the formation of key intermediates that are essential for efficient OER catalysis. Our findings offer a promising strategy for the design of high-performance catalysts for water oxidation and sustainable electrocatalysis.

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Fig. 1: CV and OER activity of iron molecular complexes.
Fig. 2: In situ XAS measurements of L1Fe.
Fig. 3: In situ non-resonant Kβ emission spectra of L1Fe.
Fig. 4: In situ HERFD-XAS of L1Fe.
Fig. 5: OER mechanisms of L1Fe.

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Data availability

All data that support the findings of this study are available within the article and its Supplementary Information. The source data are available via Zenodo at https://zenodo.org/uploads/15117987 (ref. 76).

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Acknowledgements

H.M.C. and C.W.T. acknowledge support from the National Science and Technology Council, Taiwan (contract numbers NSTC 111-2628-M-002-010-RSP, 113-2123-M-002-005, 113-2639-M-002-009-ASP, 112-2926-I-002-513-G and 112-2113-M-131-002-MY2), the MCUT Formosa Center and from National Taiwan University (NTU-CC-113L893304). W.Z. is supported by the National Natural Science Foundation of China (grant number 22208126), the Natural Science Foundation of Jiangsu Province (grant number BK20210774) and the Scientific Research Startup Foundation of Jiangsu University (grant number 2021JDG025). X.C.Z. acknowledges support from Hong Kong Global STEM Professorship Scheme. We thank the interdisciplinary project of NSRRC for providing assistance with the synchrotron-based X-ray experiments.

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  1. These authors contributed equally: Ching-Wei Tung, Wei Zhang.

Authors and Affiliations

  1. Department of Chemistry, National Taiwan University, Taipei, Taiwan

    Ching-Wei Tung, Tai Ying Lai, Jiali Wang, You-Chiuan Chu, Guan-Bo Wang & Hao Ming Chen

  2. Department of Materials Engineering, Ming Chi University of Technology, New Taipei City, Taiwan

    Ching-Wei Tung

  3. Center for Environmental Sustainability and Human Health, Ming Chi University of Technology, New Taipei City, Taiwan

    Ching-Wei Tung

  4. Institute for Energy Research, Jiangsu University, Zhenjiang, China

    Wei Zhang

  5. National Synchrotron Radiation Research Center, Hsinchu, Taiwan

    Chia-Shuo Hsu, Yen-Fa Liao, Nozomu Hiraoka, Hirofumi Ishii & Hao Ming Chen

  6. Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong SAR, China

    Xiao Cheng Zeng

  7. Hong Kong Institute for Clean Energy, City University of Hong Kong, Hong Kong SAR, China

    Xiao Cheng Zeng

  8. Center for Emerging Materials and Advanced Devices, National Taiwan University, Taipei, Taiwan

    Hao Ming Chen

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Contributions

C.-W.T. conceived and performed the catalyst synthesis, electrochemical measurements, in situ synchrotron spectroscopy experiments, data analysis and wrote the paper. W.Z. conducted the DFT calculations. T.Y.L. performed the in situ spectroscopy measurements and carried out related theoretical calculations. J.W. assisted in the spectral data analysis. Y.-C.C. contributed to the electrochemical data analysis. G.-B.W. contributed to the spectral analysis. C.-S.H., Y.-F.L., N.H. and H.I. supported the setting up and interpretation of the synchrotron spectroscopy experiments. X.C.Z. contributed to theoretical insights and paper editing. H.M.C. supervised the overall project and co-wrote the paper. All authors discussed the results and contributed to the final paper.

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Correspondence to Wei Zhang, Xiao Cheng Zeng or Hao Ming Chen.

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Nature Sustainability thanks Boniface P. T. Fokwa, Lizhe Liu and Shiming Zhou for their contribution to the peer review of this work.

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Experimental section, Figs. 1–63, Tables 1–13 and References.

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Tung, CW., Zhang, W., Lai, T.Y. et al. Spin crossover-driven diiron electrocatalyst boosts sustainable water oxidation. Nat Sustain 8, 793–805 (2025). https://doi.org/10.1038/s41893-025-01571-3

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