The contributions of hydrogen as a fuel source and energy carrier are expected to expand in turn increasing exploitation of freshwater resources for the electrolytic production of this gas. Fortunately, processing technologies are being developed to alleviate pressure on limited water supplies by turning to seawater as a source of hydrogen.

A seawater-resilient bipolar membrane electrolyzer has successfully generated hydrogen gas without coproducing large amounts of harmful byproducts. The system designed by researchers from Stanford University, University of Oregon, Manchester Metropolitan University (U.K.) and SLAC National Accelerator Laboratory effectively electrolyzes impure seawater and mitigates the corrosive and potentially toxic effects of chlorides and associated oxidation products.

[See also: Green hydrogen extracted from untreated seawater]

Hydrogen ions pass through one membrane layer and are converted into hydrogen gas by interacting with the cathode. A second membrane admits only negative ions, including chloride, to travel through. This negatively charged presence proved highly efficient in blocking almost all of the chloride ions under experimental conditions, and the system operated without generating toxic byproducts such as bleach and chlorine.

The researchers will next focus on the use of abundant materials to make the electrolysis system described in the journal Joule easier to scale to a size needed to generate hydrogen for energy intensive activities.

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