The blue economy is one of the most carbon-intensive sectors globally, with shipping alone emitting over 1000 Mt CO2 annually. Decarbonising it needs a clean, energy‑dense fuel, and green hydrogen has emerged as a leading option. However, existing electrolysis systems remain centralised, relying on freshwater and poorly suited to offshore conditions. Direct seawater electrolysis (DSE) resolves this by coupling offshore renewables with seawater to produce hydrogen directly at the point of demand. This eliminates the need for dedicated desalination, potentially reducing hydrogen production costs by up to 30%. Yet deployment is constrained by competing chlorine evolution, anodic corrosion, and cathodic hydroxide precipitation. In addition, scalable seawater electrolyser architectures remain underdeveloped. Advancing DSE requires integrating catalyst innovation with durable, environmentally robust system design. Here, we connect mechanistic strategies for mitigating cathodic precipitation with an ionically bonded heterostructure design principle for anodic OER-CER selectivity, and extend both to the underexplored challenges of intermittency and membrane durability. At scale, DSE could transform energy supply in the blue economy, enabling decentralised hydrogen production directly from seawater.
- Open Access
- Perspective
Direct Seawater Electrolysis for Decentralised Hydrogen Production: Opportunities for the Blue Economy
- Vasundhara Nettem,
- Nasir Mahmood *
Author Information
Received: 01 Jun 2026 | Revised: 29 Jul 2026 | Accepted: 08 Oct 2026 | Published: 19 Oct 2026
Abstract
Keywords
direct seawater electrolysis | green hydrogen | blue economy | cathodic precipitation | ionic heterostructures | interface engineering
References
- 1.
Pires Manso, J.R.; Martínez Vázquez, R.M.; Milán García, J.; et al. Renewable Energies and Blue Economy: New Trends in Global Research. Energies 2023, 16, 4210. https://doi.org/10.3390/en16104210.
- 2.
Qureshi, F.; Asif, M.; Khan, A.; et al. Green Hydrogen Production from Non-Traditional Water Sources: A Sustainable Energy Solution with Hydrogen Storage and Distribution. Chem. Rec. 2024, 24, e202400080. https://doi.org/10.1002/tcr.202400080.
- 3.
Loomba, S.; Khan, M.W.; Mahmood, N. Seawater to Green Hydrogen: Future of Green Energy. ChemElectroChem 2023, 10, e202300471. https://doi.org/10.1002/celc.202300471.
- 4.
Ghaffour, N.; Missimer, T.M.; Amy, G.L. Technical Review and Evaluation of the Economics of Water Desalination: Current and Future Challenges for Better Water Supply Sustainability. Desalination 2013, 309, 197–207. https://doi.org/10.1016/j.desal.2012.10.015.
- 5.
Fazeli, R.; Longden, T.; Beck, F.J. Dynamics of Price-Based Competition between Blue and Green Hydrogen with Net Zero Emissions Targets. Renew. Sustain. Energy Rev. 2025, 210, 115244. https://doi.org/10.1016/j.rser.2024.115244.
- 6.
Meskher, H.; Hu, Q.; Liao, X.; et al. Prevention of Cathodic Precipitation in Seawater Electrolysis: From Mechanistic Insights to Advanced Mitigation Strategies. Adv. Funct. Mater. 2026, 36, e75602. https://doi.org/10.1002/adfm.75602.
- 7.
Travaglini, R.; Frowijn, L.S.F.; Bianchini, A.; et al. Offshore or Onshore Hydrogen Production? A Critical Analysis on Costs and Operational Considerations for the Dutch North Sea. Appl. Energy 2025, 397, 126290. https://doi.org/10.1016/j.apenergy.2025.126290.
- 8.
Guo, J.; Zheng, Y.; Hu, Z.; et al. Direct Seawater Electrolysis by Adjusting the Local Reaction Environment of a Catalyst. Nat. Energy 2023, 8, 264–272. https://doi.org/10.1038/s41560-023-01195-x.
- 9.
Liang, J.; Cai, Z.; Li, Z.; et al. Efficient Bubble/Precipitate Traffic Enables Stable Seawater Reduction Electrocatalysis at Industrial-Level Current Densities. Nat. Commun. 2024, 15, 2950. https://doi.org/10.1038/s41467-024-47121-x.
- 10.
Zhang, X.L.; Yu, P.C.; Sun, S.P.; et al. In Situ Ammonium Formation Mediates Efficient Hydrogen Production from Natural Seawater Splitting. Nat. Commun. 2024, 15, 9462. https://doi.org/10.1038/s41467-024-53724-1.
- 11.
Liu, Y.; Wang, Y.; Fornasiero, P.; et al. Long-Term Durability of Seawater Electrolysis for Hydrogen: From Catalysts to Systems. Angew. Chem. 2024, 136, e202412087. https://doi.org/10.1002/ange.202412087.
- 12.
Xu, W.; Ma, T.; Chen, H.; et al. Scalable Fabrication of Cu2S@NiS@Ni/NiMo Hybrid Cathode for High-Performance Seawater Electrolysis. Adv. Funct. Mater. 2023, 33, 2302263. https://doi.org/10.1002/adfm.202302263.
- 13.
Loomba, S.; Khan, M.W.; Haris, M.; et al. Nitrogen-Doped Porous Nickel Molybdenum Phosphide Sheets for Efficient Seawater Splitting. Small 2023, 19, 2207310. https://doi.org/10.1002/smll.202207310.
- 14.
Luo, X.; Zhao, H.; Tan, X.; et al. Fe-S Dually Modulated Adsorbate Evolution and Lattice Oxygen Compatible Mechanism for Water Oxidation. Nat. Commun. 2024, 15, 8293. https://doi.org/10.1038/s41467-024-52682-y.
- 15.
Lu, M.; Zheng, Y.; Hu, Y.; et al. Artificially Steering Electrocatalytic Oxygen Evolution Reaction Mechanism by Regulating Oxygen Defect Contents in Perovskites. Sci. Adv. 2022, 8, eabq3563. https://doi.org/10.1126/sciadv.abq3563.
- 16.
Gbadamasi, S.; Loomba, S.; Haris, M.; et al. Breaking the Inactivity of MXenes to Drive Ampere-Level Selective Oxygen Evolution Reaction in Seawater. Mater. Sci. Eng. R Rep. 2024, 160, 100835. https://doi.org/10.1016/j.mser.2024.100835.
- 17.
Mousavi, S.; Qayyum, H.A.; Khan, M.W.; et al. Interfacial Engineering to Construct Two-Dimensional Boron-Doped Iron Disulfide/Metal–Organic Framework Heterostructures for Selective Anodic Reaction in Seawater. ACS Nano 2025, 19, 31598–31608. https://doi.org/10.1021/acsnano.5c08842.
- 18.
Mousavi, S.; Qayyum, H.A.; Khan, M.W.; et al. Industrial-Scale Seawater Splitting at Engineered Interface of Boron-Doped Cobalt Sulfide/Metal–Organic Framework Nanosheets Heterostructure. Small Sci. 2026, 6, e202500497. https://doi.org/10.1002/smsc.202500497.
- 19.
Loomba, S.; Khan, M.W.; Haris, M.; et al. Interfacial Engineering to Create Ionically Bonded Heterostructures for Ampere-Level Chlorine-Free Anodic Reactions in Seawater. Appl. Catal. B Environ. Energy 2025, 363, 124800. https://doi.org/10.1016/j.apcatb.2024.124800.
- 20.
Gbadamasi, S.; Fujisaki, T.; Loomba, S.; et al. Optimising an Electron-Rich 2D Fe,B-Ti3C2Tx/N-Doped Mixed Metal Oxide Interface for Industrial-Scale Oxygen Evolution in Seawater. J. Mater. Chem. A 2026, 14, 15770–15781. https://doi.org/10.1039/d5ta10475k.
- 21.
Shen, P.; Zhu, J.; Deng, C.; et al. Dynamic Stability in Intermittent Seawater Electrolysis via Frustrated Lewis Pair Engineering. Adv. Sci. 2026, 13, e18514. https://doi.org/10.1002/advs.202518514.
- 22.
Sha, Q.; Wang, S.; Yan, L.; et al. 10,000-h-Stable Intermittent Alkaline Seawater Electrolysis. Nature 2025, 639, 360–367. https://doi.org/10.1038/s41586-025-08610-1.
- 23.
Carboni, N.; Navarra, M.A.; Passerini, S.; et al. Durability and Degradation of Anion Exchange Membranes in Water Electrolyzers. J. Mater. Chem. A 2026, 14, 9852–9881. https://doi.org/10.1039/d5ta06423f.
- 24.
Groenemans, H.; Saur, G.; Mittelsteadt, C.; et al. Techno-Economic Analysis of Offshore Wind PEM Water Electrolysis for H2 Production. Curr. Opin. Chem. Eng. 2022, 37, 100828. https://doi.org/10.1016/j.coche.2022.100828.
- 25.
dos Santos Ramos, J.; Bastos, I.T.C.; de Almeida, J.O.; et al. Isolated Offshore Wind-Powered Hydrogen Production: A Time-Domain Coupled Power Control and PEM Electrolysis Model for Transient Behavior and LCOH Analysis. Int. J. Hydrogen Energy 2025, 191, 152284. https://doi.org/10.1016/j.ijhydene.2025.152284.
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