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Cathode catalyst layers modified with Brønsted acid oxides to improve proton exchange membrane electrolysers for impure water splitting

Nature Energy volume 10, pages 880–889 (2025)Cite this article

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Abstract

Proton exchange membrane (PEM) electrolysers typically use ultrapure water as feedstock because trace contaminants in feedwater, especially cationic impurities, can cause their failure. Developing PEM electrolysers that can withstand lower-purity water could minimize water pretreatment, lower maintenance costs and extend system lifetime. In this context, we have developed a microenvironment pH-regulated PEM electrolyser that can operate steadily in impure (‘tap’) water for more than 3,000 h at a current density of 1.0 A cm−2, maintaining a performance that is comparable to state-of-the-art PEM electrolysers that use pure water. Using a technique that combines a pH ultramicroelectrode with scanning electrochemical microscopy, we monitored the local pH conditions in a PEM electrolyser in situ, finding that Brønsted acid oxides can lower the local pH. We thus introduced a Brønsted acid oxide, MoO3−x, onto a Pt/C cathode to create a strongly acidic microenvironment that boosts the kinetics of hydrogen production, inhibits deposition/precipitation on the cathode and suppresses the degradation of the membrane.

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Fig. 1: Effects of cationic impurities on PEM electrolyser performance.
Fig. 2: Generating local acidity using Brønsted acidic oxides.
Fig. 3: Performance and stability of a local pH-regulated PEM electrolyser for splitting impure water.
Fig. 4: Effect of local acidity on the membrane when operating the electrolyser in impure water containing Fe3+.
Fig. 5: Performance of a local pH-regulated PEM electrolyser in tap water and techno-economic calculations.

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The datasets generated and analysed during this study are included in the paper and its Supplementary Information. Source data are provided with this paper.

References

  1. Ayers, K. et al. Perspectives on low-temperature electrolysis and potential for renewable hydrogen at scale. Annu. Rev. Chem. Biomol. Eng. 10, 219–239 (2019).

    Article  Google Scholar 

  2. Carmo, M., Fritz, D. L., Mergel, J. & Stolten, D. A comprehensive review on PEM water electrolysis. Int. J. Hydrogen Energy 38, 4901–4934 (2013).

    Article  Google Scholar 

  3. Chu, S. & Majumdar, A. Opportunities and challenges for a sustainable energy future. Nature 488, 294–303 (2012).

    Article  Google Scholar 

  4. Lagadec, M. F. & Grimaud, A. Water electrolysers with closed and open electrochemical systems. Nat. Mater. 19, 1140–1150 (2020).

    Article  Google Scholar 

  5. Grigoriev, S. A., Fateev, V. N., Bessarabov, D. G. & Millet, P. Current status, research trends, and challenges in water electrolysis science and technology. Int. J. Hydrogen Energy 45, 26036–26058 (2020).

    Article  Google Scholar 

  6. Wang, Y., Pang, Y., Xu, H., Martinez, A. & Chen, K. S. PEM fuel cell and electrolysis cell technologies and hydrogen infrastructure development—a review. Energy Environ. Sci. 15, 2288–2328 (2022).

    Article  Google Scholar 

  7. Buttler, A. & Spliethoff, H. Current status of water electrolysis for energy storage, grid balancing and sector coupling via power-to-gas and power-to-liquids: a review. Renew. Sustain. Energy Rev. 82, 2440–2454 (2018).

    Article  Google Scholar 

  8. Global Energy Transformation: A Roadmap to 2050 (IRENA, 2019); https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2019/Apr/IRENA_Global_Energy_Transformation_2019.pdf

  9. Net Zero by 2050: A Roadmap for the Global Energy Sector (IEA, 2021); https://www.iea.org/reports/net-zero-by-2050

  10. Global Hydrogen Review 2023 (IEA, 2023); https://www.iea.org/reports/global-hydrogen-review-2023

  11. Tsotridis, G. & Pilenga, A. EU Harmonised Protocols for Testing of Low Temperature Water Electrolysers (Publications Office of the European Union, 2021).

  12. Becker, H. et al. Impact of impurities on water electrolysis: a review. Sustain. Energy Fuels 7, 1565–1603 (2023).

    Article  Google Scholar 

  13. Lindquist, G. A., Xu, Q., Oener, S. Z. & Boettcher, S. W. Membrane electrolyzers for impure-water splitting. Joule 4, 2549–2561 (2020).

    Article  Google Scholar 

  14. Tong, W. et al. Electrolysis of low-grade and saline surface water. Nat. Energy 5, 367–377 (2020).

    Article  Google Scholar 

  15. Feng, Q. et al. A review of proton exchange membrane water electrolysis on degradation mechanisms and mitigation strategies. J. Power Sources 366, 33–55 (2017).

    Article  Google Scholar 

  16. He, C. et al. Future global urban water scarcity and potential solutions. Nat. Commun. 12, 4667 (2021).

    Article  Google Scholar 

  17. Kumar, P., Date, A., Mahmood, N., Das, R. K. & Shabani, B. Freshwater supply for hydrogen production: an underestimated challenge. Int. J. Hydrogen Energy 78, 202–217 (2024).

    Article  Google Scholar 

  18. Thomassen, M. S., Reksten, A. H., Barnett, A. O., Khoza, T. & Ayers, K. in Electrochemical Power Sources: Fundamentals, Systems, and Applications (eds Smolinka, T. and Garche, J.) Ch. 6 (Elsevier, 2022).

  19. Mayyas, A., Ruth, M., Pivovar, B., Bender, J. & Wipke, K. Manufacturing Cost Analysis for Proton Exchange Membrane Water Electrolyzers (NREL, 2019).

  20. Kheirrouz, M., Melino, F. & Ancona, M. A. Fault detection and diagnosis methods for green hydrogen production: a review. Int. J. Hydrogen Energy 47, 27747–27774 (2022).

    Article  Google Scholar 

  21. Wang, X. et al. The influence of ferric ion contamination on the solid polymer electrolyte water electrolysis performance. Electrochim. Acta 158, 253–257 (2015).

    Article  Google Scholar 

  22. Kusoglu, A. & Weber, A. Z. New insights into perfluorinated sulfonic-acid ionomers. Chem. Rev. 117, 987–1104 (2017).

    Article  Google Scholar 

  23. Zhang, L., Jie, X., Shao, Z., Wang, X. & Yi, B. The dynamic-state effects of sodium ion contamination on the solid polymer electrolyte water electrolysis. J. Power Sources 241, 341–348 (2013).

    Article  Google Scholar 

  24. Marin, D. H. et al. Hydrogen production with seawater-resilient bipolar membrane electrolyzers. Joule 7, 765–781 (2023).

    Article  Google Scholar 

  25. Li, N., Araya, S. S. & Kær, S. K. Long-term contamination effect of iron ions on cell performance degradation of proton exchange membrane water electrolyser. J. Power Sources 434, 226755 (2019).

    Article  Google Scholar 

  26. Frensch, S. H. et al. Impact of iron and hydrogen peroxide on membrane degradation for polymer electrolyte membrane water electrolysis: computational and experimental investigation on fluoride emission. J. Power Sources 420, 54–62 (2019).

    Article  Google Scholar 

  27. Subbaraman, R. et al. Enhancing hydrogen evolution activity in water splitting by tailoring Li+-Ni(OH)2-Pt interfaces. Science 334, 1256–1260 (2011).

    Article  Google Scholar 

  28. Sheng, W. et al. Correlating hydrogen oxidation and evolution activity on platinum at different pH with measured hydrogen binding energy. Nat. Commun. 6, 5848 (2015).

    Article  Google Scholar 

  29. Guo, J. et al. Direct seawater electrolysis by adjusting the local reaction environment of a catalyst. Nat. Energy 8, 264–272 (2023).

    Google Scholar 

  30. Xu, B., Sievers, C., Hong, S., Prins, R. & Vanbokhoven, J. Catalytic activity of Brønsted acid sites in zeolites: intrinsic activity, rate-limiting step, and influence of the local structure of the acid sites. J. Catal. 244, 163–168 (2006).

    Article  Google Scholar 

  31. Wen, Y. et al. Introducing Brønsted acid sites to accelerate the bridging-oxygen-assisted deprotonation in acidic water oxidation. Nat. Commun. 13, 4871 (2022).

    Article  Google Scholar 

  32. Qiu, Y. et al. Proton relay for the rate enhancement of electrochemical hydrogen reactions at heterogeneous interfaces. J. Am. Chem. Soc. 145, 26016–26027 (2023).

    Article  Google Scholar 

  33. Jiang, Y., Huang, J., Dai, W. & Hunger, M. Solid-state nuclear magnetic resonance investigations of the nature, property, and activity of acid sites on solid catalysts. Solid State Nucl. Magn. Reson. 39, 116–141 (2011).

    Article  Google Scholar 

  34. Wang, Y. H. et al. In situ Raman spectroscopy reveals the structure and dissociation of interfacial water. Nature 600, 81–85 (2021).

    Article  Google Scholar 

  35. Alsaif, M. M. Y. A. et al. Tunable plasmon resonances in two-dimensional molybdenum oxide nanoflakes. Adv. Mater. 26, 3931–3937 (2014).

    Article  Google Scholar 

  36. Chen, L., Xu, Q. & Boettcher, S. W. Kinetics and mechanism of heterogeneous voltage-driven water-dissociation catalysis. Joule 7, 1867–1886 (2023).

    Article  Google Scholar 

  37. Rodellar, C. G., Gisbert-Gonzalez, J. M., Sarabia, F., Roldan Cuenya, B. & Oener, S. Z. Ion solvation kinetics in bipolar membranes and at electrolyte–metal interfaces. Nat. Energy 9, 548–558 (2024).

    Article  Google Scholar 

  38. Oener, S. Z., Foster, M. J. & Boettcher, S. W. Accelerating water dissociation in bipolar membranes and for electrocatalysis. Science 369, 1099–1103 (2020).

    Article  Google Scholar 

  39. Tan, H. et al. Engineering a local acid-like environment in alkaline medium for efficient hydrogen evolution reaction. Nat. Commun. 13, 2024 (2022).

    Article  Google Scholar 

  40. Wang, X., Xu, C., Jaroniec, M., Zheng, Y. & Qiao, S.-Z. Anomalous hydrogen evolution behavior in high-pH environment induced by locally generated hydronium ions. Nat. Commun. 10, 4876 (2019).

    Article  Google Scholar 

  41. Oki, T. & Kanae, S. Global hydrological cycles and world water resources. Science 313, 1068–1072 (2006).

    Article  Google Scholar 

  42. Tonelli, D. et al. Global land and water limits to electrolytic hydrogen production using wind and solar resources. Nat. Commun. 14, 5532 (2023).

    Article  Google Scholar 

  43. H2A-Lite: Hydrogen Analysis Lite Production Model (National Renewable Energy Laboratory, 2022); https://www.nrel.gov/hydrogen/h2a-lite.html

  44. El-Shafie, M. Hydrogen production by water electrolysis technologies: a review. Results Eng. 20, 101426 (2023).

    Article  Google Scholar 

  45. Schwartz, J. et al. Real-time 3D analysis during electron tomography using tomviz. Nat. Commun. 13, 4458 (2022).

    Article  Google Scholar 

  46. Zhu, Z., Ye, Z., Zhang, Q., Zhang, J. & Cao, F. Novel dual Pt-Pt/IrOx ultramicroelectrode for pH imaging using SECM in both potentiometric and amperometric modes. Electrochem. Commun. 88, 47–51 (2018).

    Article  Google Scholar 

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Acknowledgements

This work was supported by the National Natural Science Foundation of China (U23A2086 and 52071231) and the Natural Science Foundation of Tianjin City (19JCJQJC61900).

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Author notes

  1. These authors contributed equally: Ruguang Wang, Yuting Yang, Jiaxin Guo.

Authors and Affiliations

  1. School of Materials Science and Engineering, Tianjin University, Tianjin, China

    Ruguang Wang, Jiaxin Guo & Tao Ling

  2. Department of Economics, University of New Mexico, Albuquerque, NM, USA

    Yuting Yang

  3. Institute of Atomic Manufacturing, Beihang University, Beijing, China

    Jiaxin Guo

  4. School of Materials, Sun Yat-sen University, Shenzhen, China

    Qinhao Zhang & Fahe Cao

  5. State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, China

    Yunjian Wang & Lili Han

Authors
  1. Ruguang Wang
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Contributions

T.L. conceived the project and designed the experiments. R.W. and J.G. performed the experiments. Y.Y. conducted the techno-economic analysis. F.C. and Q.Z. carried out the SECM measurements and fabricated the Pt/IrO2 ultramicroelectrode. Y.W. and L.H. analysed the TEM data. T.L. and R.W. wrote the paper. T.L. and Y.Y. reviewed and corrected the paper. All authors discussed the results and commented on the paper.

Corresponding author

Correspondence to Tao Ling.

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Nature Energy thanks Michael Busch, Yagya Regmi and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Information

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Wang, R., Yang, Y., Guo, J. et al. Cathode catalyst layers modified with Brønsted acid oxides to improve proton exchange membrane electrolysers for impure water splitting. Nat Energy 10, 880–889 (2025). https://doi.org/10.1038/s41560-025-01787-9

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