Self-cleaning dual cathode for enhanced durability of bipolar membrane-based direct seawater electrolysis

초록

Direct seawater electrolysis offers a sustainable route to green hydrogen but remains limited by cathodic passivation caused by inorganic precipitate growth. Herein, we report a bipolar-membrane-based direct seawater electrolysis system integrating a dual-cathode configuration that enables self-cleaning of the cathode during long-term electrolysis. The two Pt/MoS2 cathodes operate alternately every 48 h, allowing the inactive electrode to dissolve surface precipitates in the acidified seawater (pH similar to 2), while the other sustains the hydrogen evolution reaction (HER). This approach enables continuous hydrogen production without operational shutdowns, suppresses excessive scaling, and stabilizes cathodic potentials for over 400 h at 100 mA cm(-2). Compared with the single-cathode system, which exhibited severe passivation, high interfacial resistance, and significant Pt loss, the dual-cathode system preserved the structural integrity of MoS2 nanosheets and Pt nanoparticles, demonstrating enhanced durability. Although HER activity partially degrades over long-term operation, the proposed dual-cathode self-cleaning strategy provides a practical solution to mitigate precipitation-induced cathodic passivation in direct seawater electrolysis and offers a viable pathway toward durable, scalable hydrogen production from natural seawater.

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