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Cost-efficient and stable electrolysis of reverse osmosis water using a Co-RuO2-enabled PEM electrolyser

Nature Catalysis volume 9, pages 9–17 (2026)Cite this article

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Abstract

The durability of proton-exchange-membrane water electrolysers (PEMWE) is strongly influenced by the purity of the feedwater. Reverse osmosis (RO) is a cost-effective purification method, but the residual ions usually cause rapid degradation. Here we show that a standard PEMWE equipped with a cobalt-doped ruthenium dioxide (Co–RuO2) anode catalyst can operate stably for 2,000 h at 1.0 A cm−2 using RO-level impure water, with a degradation rate of 10.2 μV h−1. The catalyst provides two complementary protections: Co sites selectively and reversibly capture chloride ions (Cl−), forming a shielding layer against anions corrosion, and strain-activated Ru sites create a proton-rich interface that blocks impurity cations. Together, these effects maintain electrode activity and membrane conductivity. As a result, RO water electrolysis achieves a durability comparable to pure water operation while retaining the cost benefits of seawater-derived purification, offering a practical route towards efficient and affordable hydrogen production.

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Fig. 1: Cost comparison of RO and DI water purification processes and a feasibility test of an RO water operation in PEMWEs.
Fig. 2: Electrochemical tests and stability origin.
Fig. 3: Concept verification under practical conditions by a PEMWE fed with RO water at 60 °C (anode, Co–RuO2; cathode, Pt/C).
Fig. 4: Evaluation of cation tolerance and the underlying mechanism of the Co–RuO2 catalyst.
Fig. 5: Assessment of anion-blocking capability and the dual interfacial protection mechanism.
Fig. 6: Validation of multi-scenario applications of our impure water electrolysis system.

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Data availability

The data supporting the findings of this study are available within the paper and its Supplementary Information. Additional data supporting the findings of this study are available from the corresponding author upon reasonable request. Source data are provided with this paper.

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Acknowledgements

S.-Z.Q. acknowledges financial support provided by the Australian Research Council through the Discovery and Linkage Project Programs (DP230102027, IL230100039 and CE230100032). Y.Z. acknowledges financial support provided by the Australian Research Council through the Discovery and Linkage Project Programs (DP240102575 and CE230100032). We acknowledge Y. Hu at Lanzhou University for support with microscopy analysis. We acknowledge the Australian Synchrotron for access to the beamline facilities (mode 3).

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Authors and Affiliations

  1. School of Chemical Engineering, The University of Adelaide, Adelaide, South Australia, Australia

    Hao Liu, Xiaogang Sun, Fei-Yue Gao, Yao Zheng & Shi-Zhang Qiao

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  1. Hao Liu
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  2. Xiaogang Sun
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  3. Fei-Yue Gao
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  4. Yao Zheng
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Contributions

Y.Z. and S.-Z.Q. conceived and supervised the work. H.L. designed and carried out experiments. X.S. and H.L. conducted the technology economic analysis. H.L. and F.-Y.G. conducted the PEMWE tests. H.L., Y.Z. and S.-Z.Q. wrote and corrected the paper. All authors approved the final version of the paper.

Corresponding authors

Correspondence to Yao Zheng or Shi-Zhang Qiao.

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Competing interests

H.L., Y.Z. and S.-Z.Q. are inventors on a patent application related to the technology described in this work.

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Nature Catalysis thanks Mark Mba-Wright, Ryuhei Nakamura and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary Notes 1 and 2, Figs. 1–34, Table 1 and References.

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Liu, H., Sun, X., Gao, FY. et al. Cost-efficient and stable electrolysis of reverse osmosis water using a Co-RuO2-enabled PEM electrolyser. Nat Catal 9, 9–17 (2026). https://doi.org/10.1038/s41929-025-01456-w

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