Researchers can now pull hydrogen directly from seawater, no filtering required

It could eventually produce cheap, renewable energy for coastal areas.

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Researchers at the University of Adelaide announced this week that they made clean hydrogen fuel from seawater without pre-treatment. Demand for hydrogen fuel, a clean energy source that only produces water when burned, is expected to increase in the coming years as the world (hopefully) continues to pivot away from fossil fuels. The findings could eventually provide cheaper green energy production to coastal areas.

“We have split natural seawater into oxygen and hydrogen with nearly 100 per cent efficiency, to produce green hydrogen by electrolysis, using a non-precious and cheap catalyst in a commercial electrolyser,” said Professor Shizhang Qiao, the team’s co-lead. Seawater typically needs to be purified before electrolysis splits it into hydrogen and oxygen. The team says its results, using cobalt oxide with chromium oxide on its surface as the catalyst, had similar performance to a standard process of applying platinum and iridium catalysts to highly purified and deionized water.

Compared to freshwater, seawater is an abundant resource, and the ability to extract hydrogen fuel from seawater without pre-treatment could save money. However, even if successfully scaled, it would likely only be practical for coastal communities with plenty of seawater — not so much for Iowa or Kansas.

The team’s next step is to scale the system with a larger electrolyzer. Then, although it’s still early in development, the researchers hope to eventually apply the findings to commercial hydrogen production for fuel cells and ammonia synthesis. Co-lead Yao Zheng summarized, “Our work provides a solution to directly utilise seawater without pre-treatment systems and alkali addition, which shows similar performance as that of existing metal-based mature pure water electrolyser.”

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