Membrane-regulated seawater electrolysis for sustainable hydrogen production

Direct seawater electrolysis (DSE) has emerged as a promising pathway for sustainable hydrogen production, yet its practical deployment remains constrained by inorganic scaling, chlorine-induced corrosion, parasitic reactions, and unstable interfacial environments inherent to complex seawater matrices. While recent efforts have largely focused on electrocatalyst and electrolyzer design, membrane-regulated strategies introduce an alternative route by regulating water and ion transport at the system level. This review critically evaluates how osmotic-, electric-field-, and vapor-pressure-driven membrane processes reshape the reaction environment in DSE, with emphasis on their roles in mitigating fouling, scaling, and chlorine chemistry under realistic conditions. Three representative pathways-osmotic-driven water supply, bipolar-membrane-enabled pH regulation, and vapor-phase separation-are comparatively assessed in terms of transport mechanisms, environmental robustness, and operational trade-offs. Beyond performance metrics, particular attention is given to challenges associated with membrane fouling, long-term stability, and the mismatch between laboratory models and natural seawater systems. By integrating perspectives from membrane science and water treatment, this review highlights the opportunities and limitations of membrane-enabled DSE, and outlines key directions toward environmentally sustainable and scalable hydrogen production in water-stressed and coastal regions.