Researchers in China claim to have produced hydrogen from seawater without the need to desalinate or purify it first, according to a report in Chemistry World.
Since seawater is abundant, making up 96% of the world’s water, this development could be a game-changer in driving hydrogen production costs downs.
“What they’ve done is really quite challenging from a chemistry perspective,” explained Professor Alex Cowan, who researches sustainable fuels at Liverpool University in the UK to the Financial Times. “This technology hits a potential niche market that hasn’t been addressed before.”
In most cases, seawater is desalinated before it undergoes electrolysis because salt and other impurities can destroy the electrolyser. Adding desalination to the mix can add cost to the hydrogen production process.
Heping Xie at Shenzhen University and Zongping Shao at Nanjing Tech University have come up with a solution. They used a waterproof permeable membrane to segregate the electrolyzer from the water, preventing anything other than pure water vapour from reaching the electrolyzer. The electrolyzer then converts the vapour to hydrogen.
The scientists installed a prototype in China’s Shenzhen Bay that produced more than 1million liters of hydrogen over 133 days without a reported decrease in production. “Running it for more than 3,000 hours sets a new benchmark in stability,” Cowan said.
Potentially, this method could be used offshore to power seawater electrolyzers, similar to the Gigastack project in the Humber estuary off the Northern English coast where offshore wind is being used to power electrolyzers. The resulting hydrogen is being used at the Humber refinery.