(CN) – Earth’s oceans could hold the key to one day powering our lives with hydrogen fuel, according to researchers who successfully gleaned hydrogen from saltwater in the San Francisco Bay.
Previous applications of this process relied on using highly purified water – in short supply everywhere but especially in California. But using a new electrolysis process, researchers coated positively charged anodes underwater with layers that were rich in negative charges.
They published their findings Monday Proceedings of the National Academy of Sciences.
The concept of hydrogen power is the stuff of science fiction novels. Theoretically, to power cities and cars, "you need so much hydrogen it is not conceivable to use purified water," said Hongjie Dai, a J.G. Jackson and C.J. Wood professor in chemistry at Stanford and co-senior author on the paper. "We barely have enough water for our current needs in California."
Typically, negatively charged chloride in seawater corrodes the positive ends of an anode during the electrolysis process, which limits the entire application.
But this new method allows for the repelling of chloride and slows down the decay of the underlying anode metal. Researchers from Stanford University used nickel-iron hydroxide on top of nickel sulfide, according to the study. The nickel foam acted as a conductor and transported electricity from the power source and that in turn allowed the nickel-iron hydroxide to spark the electrolysis.
During this electrolysis, the sulfide turned into a negatively charged layer that protected the anode from corrosion and the team separated the oxygen and hydrogen.
Without that protection in place, the process would only work for about 12 hours in saltwater, according to the study’s authors. Previous attempts in separate studies ran low amounts of electricity to split the saltwater for hydrogen fuel in order to avoid corrosion.
But in Monday’s study the researchers were able to use up to 10 times more electricity through their device and matched the same results from electrolysis applications that use purified water.
Researchers say the new method will make hydrogen fuel – which does not emit greenhouse gases when burned – more easily available through solar or wind energy. They also see a future where the process could be applied to generate oxygen underwater for divers or submarines.
Funding was provided by the U.S. Department of Energy, National Science Foundation, National Science Foundation of China, National Key Research and Development Project of China.
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