What changed
A team at the Chinese Academy of Sciences’ Institute of Physical and Chemical Technology has proposed using alternating current to electrolyze seawater directly into hydrogen. By reversing electrode polarity, the process consumes hydroxide ions in place and suppresses the magnesium- and calcium-based deposits that undermine conventional seawater electrolysis. The team validated the concept in three reaction systems, and the findings were published in Angewandte Chemie.
Why it matters
The obstacle here is not finding seawater. It is keeping the equipment from gradually coating itself in mineral scale.
Traditional direct-current systems need seawater pretreatment and ion-exchange membranes because hydroxide ions formed during electrolysis react with magnesium and calcium. The resulting deposits can cover active sites, clog membranes and increase electrical resistance. The proposed alternating-current approach is designed to clear that chemistry as it happens, potentially removing two costly layers of system complexity.
That opens a more direct link between offshore renewable electricity and hydrogen production: power generated at sea could be used there to make hydrogen, without first relying on freshwater or extensive seawater treatment. The team also coupled the process with ethylene glycol oxidation to produce glycolic acid alongside hydrogen, giving the system a possible second source of value.
The informed outlook is promising but still narrow. The concept has been demonstrated in laboratory reaction systems, not in long-duration offshore operation. The next meaningful test is whether the approach can maintain efficiency, durability, output and cost advantages at a scale relevant to real renewable-energy projects.
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