Splitting water using electrolysis is relatively straightforward, and is already done in some hydrogen-generating facilities with access to a conventional water supply. The process, which takes place in an electrolyser, electrically separates hydrogen from oxygen and allows the hydrogen to be siphoned off. But with seawater this is more complicated because salt and other impurities can effectively destroy the electrolyser.
One option is to desalinate and purify seawater before processing it — but in some settings that can add cost. Another option is to treat the electrolyser components chemically to avoid corrosion, but that is viewed as impractical.
Now Heping Xie at Shenzhen University and Zongping Shao at Nanjing Tech University have come up with a workaround. They kept the electrolyser separate from the seawater with a waterproof, breathable membrane. A bit like a sieve, the membrane keeps anything other than pure water vapour from entering the electrolyser. As the water vapour is drawn in and converted to hydrogen, more is pulled in from the seawater to take its place. It is, they reported recently in the journal Nature, a self-sustaining system.
Chinese researchers claim to have produced hydrogen by splitting seawater without the need to desalinate or purify it first, according to a report in Chemistry World magazine https://t.co/g4Q7HdGBex
— Financial Times (@FinancialTimes) December 14, 2022