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.

A membrane-based seawater electrolyser for hydrogen generation

Abstract

Electrochemical saline water electrolysis using renewable energy as input is a highly desirable and sustainable method for the mass production of green hydrogen1,2,3,4,5,6,7; however, its practical viability is seriously challenged by insufficient durability because of the electrode side reactions and corrosion issues arising from the complex components of seawater. Although catalyst engineering using polyanion coatings to suppress corrosion by chloride ions or creating highly selective electrocatalysts has been extensively exploited with modest success, it is still far from satisfactory for practical applications8,9,10,11,12,13,14. Indirect seawater splitting by using a pre-desalination process can avoid side-reaction and corrosion problems15,16,17,18,19,20,21, but it requires additional energy input, making it economically less attractive. In addition, the independent bulky desalination system makes seawater electrolysis systems less flexible in terms of size. Here we propose a direct seawater electrolysis method for hydrogen production that radically addresses the side-reaction and corrosion problems. A demonstration system was stably operated at a current density of 250 milliamperes per square centimetre for over 3,200 hours under practical application conditions without failure. This strategy realizes efficient, size-flexible and scalable direct seawater electrolysis in a way similar to freshwater splitting without a notable increase in operation cost, and has high potential for practical application. Importantly, this configuration and mechanism promises further applications in simultaneous water-based effluent treatment and resource recovery and hydrogen generation in one step.

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

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Fig. 1: Design of the SES.
Fig. 2: Origin of continuous and highly efficient electrolysis.
Fig. 3: Scale-up and generality.

Data availability

The data that support the findings of this study are available from the corresponding authors upon reasonable request.

References

  1. Nishiyama, H. et al. Photocatalytic solar hydrogen production from water on a 100-m2 scale. Nature 598, 304–307 (2021).

    Article  ADS  CAS  Google Scholar 

  2. Dresp, S., Dionigi, F., Klingenhof, M. & Strasser, P. Direct electrolytic splitting of seawater-opportunities and challenges. ACS Energy Lett. 4, 933–942 (2019).

    Article  CAS  Google Scholar 

  3. Jin, H., Wang, X., Tang, C., Vasileff, A. & Qiao, S. Stable and highly efficient hydrogen evolution from seawater enabled by an unsaturated nickel surface nitride. Adv. Mater. 33, 2007508 (2021).

    Article  CAS  Google Scholar 

  4. Karunadasa, H. I. et al. A molecular MoS2 edge site mimic for catalytic hydrogen generation. Science 335, 698–702 (2012).

    Article  ADS  CAS  Google Scholar 

  5. Shi, L. et al. Using reverse osmosis membranes to control ion transport during water electrolysis. Energy Environ. Sci. 13, 3138–3148 (2020).

    Article  CAS  Google Scholar 

  6. Veroneau, S. S. & Nocera, D. G. Continuous electrochemical water splitting from natural water sources via forward osmosis. Proc. Natl Acad. Sci. USA 118, e2024855118 (2021).

    Article  CAS  Google Scholar 

  7. Veroneau, S. S., Hartnett, A. C., Thorarinsdottir, A. E. & Nocera, D. G. Direct seawater splitting by forward osmosis coupled to water electrolysis. ACS Appl. Energy Mater. 5, 1403–1408 (2022).

    Article  CAS  Google Scholar 

  8. Kuang, Y. et al. Solar-driven, highly sustained splitting of seawater into hydrogen and oxygen fuels. Proc. Natl Acad. Sci. USA 116, 201900556 (2019).

    Article  Google Scholar 

  9. Sun, F., Qin, J. & Wang, Z. Energy-saving hydrogen production by chlorine-free hybrid seawater splitting coupling hydrazine degradation. Nat. Commun. 12, 4182 (2021).

    Article  ADS  CAS  Google Scholar 

  10. Dresp, S., Thanh, T. N., Klingenhof, M., Brueckner, S. & Strasser, P. Efficient direct seawater electrolysers using selective alkaline NiFe-LDH as OER catalyst in asymmetric electrolyte feeds. Energy Environ. Sci. 13, 1725–1729 (2020).

    Article  CAS  Google Scholar 

  11. Yu, L., Zhu, Q., Song, S., Mcelhenny, B. & Ren, Z. Non-noble metal-nitride based electrocatalysts for high-performance alkaline seawater electrolysis. Nat. Commun. 10, 5106 (2019).

    Article  ADS  Google Scholar 

  12. Miao, J., Xiao, F. X., Yang, H. B., Khoo, S. Y. & Liu, B. Hierarchical Ni–Mo–S nanosheets on carbon fiber cloth: a flexible electrode for efficient hydrogen generation in neutral electrolyte. Sci. Adv. 1, 1500259 (2015).

    Article  ADS  Google Scholar 

  13. Dinh, C. T. et al. Multi-site electrocatalysts for hydrogen evolution in neutral media by destabilization of water molecules. Nat. Energy 4, 107–114 (2019).

    Article  CAS  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. Loutatidou, et al. Capital cost estimation of RO plants: GCC countries versus southern Europe. Desalination 347, 103–111 (2014).

    Article  CAS  Google Scholar 

  16. Caldera, U. & Breyer, C. Learning curve for seawater reverse osmosis desalination plants: capital cost trend of the past, present and future. Water Resour. Res. 53, 10523–10538 (2017).

    Article  ADS  Google Scholar 

  17. Choudhury, M. R., Anwar, N., Jassby, D. & Rahaman, M. S. Fouling and wetting in the membrane distillation driven wastewater reclamation process—a review. Adv. Colloid Interface Sci. 269, 370–399 (2019).

    Article  CAS  Google Scholar 

  18. Ahmad, N. A., Goh, P. S., Yogarathinam, L. T., Zulhairun, A. K. & Ismail, A. F. Current advances in membrane technologies for produced water desalination. Desalination 493, 114643 (2020).

    Article  CAS  Google Scholar 

  19. Generous, M. M., Qasem, N., Akbar, U. A. & Zubair, S. M. Techno-economic assessment of electrodialysis and reverse osmosis desalination plants. Sep. Purif. Technol. 272, 118875 (2021).

    Article  CAS  Google Scholar 

  20. Wang, M. et al. Ultrafast seawater desalination with covalent organic framework membranes. Nat. Sustain. 5, 518–526 (2022).

  21. Jones, E., Qadir, M., van Vliet, M. T., Smakhtin, V. & Kang, S.-M. The state of desalination and brine production: a global outlook. Sci. Total. Environ. 657, 1343–1356 (2019).

    Article  ADS  CAS  Google Scholar 

  22. Ursua, A., Gandia, L. M. & Sanchis, P. Hydrogen production from water electrolysis: current status and future trends. Proc. IEEE 100, 410–426 (2012).

    Article  CAS  Google Scholar 

  23. Yin, Y., Jeong, N. & Tong, T. The effects of membrane surface wettability on pore wetting and scaling reversibility associated with mineral scaling in membrane distillation. J. Membr. Sci. 614, 118503 (2020).

    Article  CAS  Google Scholar 

  24. Qiu, H. et al. Functional polymer materials for modern marine biofouling control. Prog. Polym. Sci. 127, 101516 (2022).

    Article  CAS  Google Scholar 

  25. Yang, K. et al. A roadmap to sorption-based atmospheric water harvesting: from molecular sorption mechanism to sorbent design and system optimization. Environ. Sci. Technol. 55, 6542–6560 (2021).

    Article  ADS  CAS  Google Scholar 

  26. Tereshchenko, & Anatoly, G. Deliquescence: hygroscopicity of water‐soluble crystalline solids. J. Pharm. Sci. 104, 3639–3652 (2015).

    Article  CAS  Google Scholar 

  27. Lan, C., Xie, H., Wu, Y., Chen, B. & Liu, T. Nanoengineered, Mo-doped, Ni3S2 electrocatalyst with increased Ni–S coordination for oxygen evolution in alkaline seawater. Energy Fuels 36, 2910–2917 (2022).

    Article  CAS  Google Scholar 

  28. Hausmann, J. N., Schlögl, R., Menezes, P. & Driess, M. Is direct seawater splitting economically meaningful? Energy Environ. Sci. 14, 3679–3685 (2021).

    Article  CAS  Google Scholar 

  29. Qtaishat, M., Matsuura, T., Kruczek, B. & Khayet, M. Heat and mass transfer analysis in direct contact membrane distillation. Desalination 219, 272–292 (2008).

    Article  CAS  Google Scholar 

  30. Matsuura, T. Synthetic Membranes and Membrane Separation Processes (CRC, 2020).

  31. Iversen, S. B., Bhatia, V. K., Dam-Johansen, K. & Jonsson, G. Characterization of microporous membranes for use in membrane contactors. J. Membr. Sci. 130, 205–217 (1997).

    Article  CAS  Google Scholar 

  32. Khalifa, A., Ahmad, H., Antar, M., Laoui, T. & Khayet, M. Experimental and theoretical investigations on water desalination using direct contact membrane distillation. Desalination 404, 22–34 (2017).

    Article  CAS  Google Scholar 

  33. Phattaranawik, J., Jiraratananon, R. & Fane, A. G. Effect of pore size distribution and air flux on mass transport in direct contact membrane distillation. J. Membr. Sci. 215, 75–85 (2003).

    Article  CAS  Google Scholar 

  34. Khayet, M., Velázquez, A. & Mengual, J. I. Modelling mass transport through a porous partition: effect of pore size distribution. J. Non Equilibrium Thermodyn. 29, 279–299 (2004).

    Article  ADS  CAS  MATH  Google Scholar 

  35. Lawson, K. W. & Lloyd, D. R. Membrane distillation. J. Membr. Sci. 124, 1–25 (1997).

    Article  CAS  Google Scholar 

  36. Balej, J. Water vapour partial pressures and water activities in potassium and sodium hydroxide solutions over wide concentration and temperature ranges. Int. J. Hydrogen Energy 10, 233–243 (1985).

    Article  CAS  Google Scholar 

  37. Chu, P. C., Fan, C. & Liu, W. T. Determination of vertical thermal structure from sea surface temperature. J. Atmos. Ocean. Technol. 17, 971–979 (2000).

    Article  ADS  Google Scholar 

  38. Levitus, S. & Boyer, T. P. World Ocean Atlas 1994. Volume 4. Temperature (National Environmental Satellite, Data, and Information Service, 1994).

  39. Straub, A. P., Yip, N. Y., Lin, S., Lee, J. & Elimelech, M. Harvesting low-grade heat energy using thermo-osmotic vapour transport through nanoporous membranes. Nat. Energy 1, 16090 (2016).

    Article  ADS  CAS  Google Scholar 

Download references

Acknowledgements

This work is supported by the National Natural Science Foundation of China (grant numbers 52004166, 52104400 and 51827901) and the Science and Technology Department of Sichuan Province (grant number 2020YFH0012). We thank the Program for Guangdong Introducing Innovative and Entrepreneurial Teams (grant number 2019ZT08G315), and we thank the Institute of New Energy and Low-Carbon Technology, Sichuan University for support.

Author information

Authors and Affiliations

Authors

Contributions

H.X., T.L. and Z.S. conceived and designed the project. Z.Z., Y.W. and C.L. performed the characterizations and experiments. Z.Z., T.L., W.J. and Y.W. analysed the data. L.Z. and D.Y. designed the devices. H.X., Z.Z., T.L., Y.W. and Z.S. drafted the article and revised it critically. All authors reviewed the manuscript.

Corresponding authors

Correspondence to Heping Xie or Zongping Shao.

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.

Additional information

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

Extended data figures and tables

Extended Data Fig. 1 In situ seawater splitting of SES and conventional seawater direct splitting.

a, A schematic diagram of the lab-scale SES. b, Photos of the lab-scale SES and operation process. c, Ion chromatography tests show that the gas path can prevent seawater penetration, so the ion content in SDE is still nearly four orders of magnitude lower than that in seawater after long-term electrolysis. d, The energy consumption analysis. From the whole period, assuming that the water source is seawater, it is necessary to desalination before use in industrial alkaline electrolysis, which needs to consume at least 9–14.4 kJ \({\rm{k}}{{\rm{g}}}_{{\rm{water}}}^{-1}\), while the phase transition of SES is a spontaneous process, which saves the energy of desalination. During electrolysis, the energy input of our strategy is equivalent to industrial alkaline water electrolysis when the system conditions are the same, which has been confirmed above. e, Electrolysis durability test of conventional direct seawater (Shenzhen Bay seawater) splitting with commercial electrocatalysts. The inset shows photos of clear seawater before electrolysis, precipitation in seawater during electrolysis, and catalyst electrode dissolving and shedding in seawater after electrolysis.

Extended Data Fig. 2 Characteristics of the PTFE membrane and directional gas path.

a, Photograph and SEM images of the PTFE membrane. b, Fourier transform infrared spectroscopy (FTIR) result shows different chemical vibration bonds of PTFE. The two bands located at 1147 and 1202 cm−1 are assigned to the -CF2 stretching vibrations of PTFE, and the 638 cm−1 peak is the -CF2 wagging vibrations of PTFE. Due to the large electronegativity and small radius of F atoms, the PTFE membrane has a lower surface energy, thus resulting in an excellent hydrophobic characteristic. The inset demonstrates the superhydrophobic property of the PTFE membrane, and the average droplet contact angle in air was measured as 156.3°. Each mean value was calculated from five measurements. c, The breakthrough pressure and corresponding theoretical hydrostatic depth of the PTFE membrane with different pore sizes. The curve of water migration mass over time at different membrane areas (d), gas path lengths (e) and pore sizes (f). In this process, the electrolysis reaction was not involved. Each mean value was calculated from three measurements.

Extended Data Fig. 3 Water phase transition migration from seawater to the SDE.

a, The average migration rate curve of water showing a fast migration rate induced by KOH electrolyte (SDE) under a vapour pressure difference. b, Photograms of the phase transition migration of seawater. c, The relationship curve of the water migration rate and SDE concentration. The inset shows the amount of water migration in simulated seawater (under conditions of 1 μm pore size and 9.6 cm2 gas path area, KOH solid as initial SDE). d, LSV scans of commercial catalysts (MoNi/NF anode paired with a PtNi mesh cathode) taken in various concentrations of KOH solution (SDE) at room temperature.

Extended Data Fig. 4 Spatiotemporal adaptivity.

ad, Water migration rate from seawater to 30-wt% KOH electrolyte (SDE) in various seasons (the average temperature is considered to be 20 °C-spring, 30 °C-summer, 10 °C-autumn and 0 °C-winter). The inset demonstrates that at different seasonal temperatures the water vapour pressure of the SDE generally increases with water migration until it is equal to that of the seawater side. e, The curve shows the variation in water vapour pressure and water vapour pressure difference with depths.

Extended Data Fig. 5 A schematic diagram and performance of the scaled-up SES.

a, The scaled-up SES consists of an electrolytic module composed by 11 cells in parallel. The structure of each cell from left to right: positioning frame, anode plate, MoNi/NF anode catalyst layer, diaphragm, and cathode. The PTFE membrane was lined on the five inner walls of the electrolyser box (except the top) to create a gas path in seawater and hold KOH solution (SDE) at the same time. b, LSV curves of the scaled-up SES compared with the lab-scale SES by measuring the voltage at 0, 10, 50, 100, 150, 200 and 250 mA cm−2 current densities.

Extended Data Fig. 6 Fouling and corrosion detection.

SEM images of the PTFE membrane before (a) and after (b) 15 days of electrolysis in SES. SEM images for the MoNi/NF anode catalyst before (c) and after (d) 200 h electrolysis in a scaled-up SES.

Extended Data Fig. 7 Hydrogen production of hygroscopic hydrogel SDE.

a, Schematic of hydrogen production using a hygroscopic PEM based on a phase transition migration mechanism. b, Electrolyte durability test for PAMPS at a constant current of 30 mA cm−2. The inset is a diagram of the PAMPS hygroscopic hydrogel SDE. c, Schematic of hydrogen production using a hygroscopic AEM based on a phase transition migration mechanism. d, Electrolyte durability test for PVA/KOH at a constant current of 250 mA cm−2. The inset is the diagram of the PVA/KOH hygroscopic hydrogel SDE.

Extended Data Fig. 8 Performance of SES based on the Mo-Ni3S2/NF anode and PtNi mesh cathode.

a, OER polarization of Mo-Ni3S2/NF and MoNi/NF electrocatalysts in 30-wt% KOH (SDE). b, LSV scans of PtNi//Mo-Ni3S2/NF and PtNi//MoNi/NF in 30-wt% KOH solution (SDE) (in H-type electrolytic cell). c, Seawater electrolysis durability test based on the Mo-Ni3S2/NF anode and PtNi mesh cathode at a constant current density of 250 mA cm−2 in SES.

Extended Data Fig. 9 Application in various impurity water solutions.

a, Water migration behaviour under different concentrations of H2SO4 solution (50 wt% KOH solution as the initial SDE). Each mean value was calculated from three measurements. b, Electrolysis durability in 0.5 M H2SO4 solution. c, The water migration behaviour under different concentration of NaOH solution (50 wt% KOH solution as the initial SDE). Each mean value was calculated from three measurements. d, Electrolysis durability in 0.5 M NaOH solution. e, The water migration behaviour under different concentrations of NaCl solution (50 wt% KOH solution as the initial SDE). Each mean value was calculated from three measurements. f, Electrolysis durability in saturated NaCl solution.

Extended Data Fig. 10 Lithium enrichment coupled with one-step hydrogen generation based on the phase transition migration mechanism.

a, Schematic illustration of continuously enriching lithium from the feed solution through water migration and hydrogen generation. b, Photos of LiCl solution without precipitation when adding K2CO3 solution before concentration, LiCl solution with precipitation when adding K2CO3 solution after concentration, and the final Li2CO3 production. c, Electrolytic durability test for hydrogen production while lithium enrichment at a constant current of 400 mA cm−2.

Supplementary information

Supplementary Information

This file contains Supplementary Figs. 1–7, Tables 1–3 and reference.

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

Xie, H., Zhao, Z., Liu, T. et al. A membrane-based seawater electrolyser for hydrogen generation. Nature 612, 673–678 (2022). https://doi.org/10.1038/s41586-022-05379-5

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41586-022-05379-5

Comments

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.

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