Nav: Home

Researchers create hydrogen fuel from seawater

March 18, 2019

Stanford researchers have devised a way to generate hydrogen fuel using solar power, electrodes and saltwater from San Francisco Bay.

The findings, published March 18 in Proceedings of the National Academy of Sciences, demonstrate a new way of separating hydrogen and oxygen gas from seawater via electricity. Existing water-splitting methods rely on highly purified water, which is a precious resource and costly to produce.

Theoretically, to power cities and cars, "you need so much hydrogen it is not conceivable to use purified water," said Hongjie Dai, 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."

Hydrogen is an appealing option for fuel because it doesn't emit carbon dioxide, Dai said. Burning hydrogen produces only water and should ease worsening climate change problems.

Dai said his lab showed proof-of-concept with a demo, but the researchers will leave it up to manufacturers to scale and mass produce the design.

Tackling corrosion

As a concept, splitting water into hydrogen and oxygen with electricity - called electrolysis - is a simple and old idea: a power source connects to two electrodes placed in water. When power turns on, hydrogen gas bubbles out of the negative end - called the cathode - and breathable oxygen emerges at the positive end - the anode.

But negatively charged chloride in seawater salt can corrode the positive end, limiting the system's lifespan. Dai and his team wanted to find a way to stop those seawater components from breaking down the submerged anodes.

The researchers discovered that if they coated the anode with layers that were rich in negative charges, the layers repelled chloride and slowed down the decay of the underlying metal.

They layered nickel-iron hydroxide on top of nickel sulfide, which covers a nickel foam core. The nickel foam acts as a conductor - transporting electricity from the power source - and the nickel-iron hydroxide sparks the electrolysis, separating water into oxygen and hydrogen. During electrolysis, the nickel sulfide evolves into a negatively charged layer that protects the anode. Just as the negative ends of two magnets push against one another, the negatively charged layer repels chloride and prevents it from reaching the core metal.

Without the negatively charged coating, the anode only works for around 12 hours in seawater, according to Michael Kenney, a graduate student in the Dai lab and co-lead author on the paper. "The whole electrode falls apart into a crumble," Kenney said. "But with this layer, it is able to go more than a thousand hours."

Previous studies attempting to split seawater for hydrogen fuel had run low amounts of electric current, because corrosion occurs at higher currents. But Dai, Kenney and their colleagues were able to conduct up to 10 times more electricity through their multi-layer device, which helps it generate hydrogen from seawater at a faster rate.

"I think we set a record on the current to split seawater," Dai said.

The team members conducted most of their tests in controlled laboratory conditions, where they could regulate the amount of electricity entering the system. But they also designed a solar-powered demonstration machine that produced hydrogen and oxygen gas from seawater collected from San Francisco Bay.

And without the risk of corrosion from salts, the device matched current technologies that use purified water. "The impressive thing about this study was that we were able to operate at electrical currents that are the same as what is used in industry today," Kenney said.

Surprisingly simple

Looking back, Dai and Kenney can see the simplicity of their design. "If we had a crystal ball three years ago, it would have been done in a month," Dai said. But now that the basic recipe is figured out for electrolysis with seawater, the new method will open doors for increasing the availability of hydrogen fuel powered by solar or wind energy.

In the future, the technology could be used for purposes beyond generating energy. Since the process also produces breathable oxygen, divers or submarines could bring devices into the ocean and generate oxygen down below without having to surface for air.

In terms of transferring the technology, "one could just use these elements in existing electrolyzer systems and that could be pretty quick," Dai said. "It's not like starting from zero - it's more like starting from 80 or 90 percent."
-end-


Stanford University

Related Hydrogen Articles:

Hydrogen boride nanosheets: A promising material for hydrogen carrier
Researchers at Tokyo Institute of Technology, University of Tsukuba, and colleagues in Japan report a promising hydrogen carrier in the form of hydrogen boride nanosheets.
World's fastest hydrogen sensor could pave the way for clean hydrogen energy
Hydrogen is a clean and renewable energy carrier that can power vehicles, with water as the only emission.
Chemical hydrogen storage system
Hydrogen is a highly attractive, but also highly explosive energy carrier, which requires safe, lightweight and cheap storage as well as transportation systems.
Observing hydrogen's effects in metal
Microscopy technique could help researchers design safer reactor vessels or hydrogen storage tanks.
The 'Batman' in hydrogen fuel cells
In a study published in Nature on Jan. 31, researchers at the University of Science and Technology of China (USTC) report advances in the development of hydrogen fuel cells that could increase its application in vehicles, especially in extreme temperatures like cold winters.
Paving the way for more efficient hydrogen cars
Hydrogen-powered vehicles emit only water vapor from their tailpipes, offering a cleaner alternative to fossil-fuel-based transportation.
New catalyst produces cheap hydrogen
QUT chemistry researchers have discovered cheaper and more efficient materials for producing hydrogen for the storage of renewable energy that could replace current water-splitting catalysts.
The faint glow of cosmic hydrogen
A study published recently in Nature magazine, in which Ana Monreal-Ibero, a researcher at the Instituto de Astrofísica de Canarias (IAC) is a participant, reveals the presence of a hitherto undetected component of the universe: large masses of gas surrounding distant galaxies.
New technology improves hydrogen manufacturing
INL researchers demonstrated high-performance electrochemical hydrogen production at a lower temperature than had been possible before.
Hydrogen transfer: One thing after the other
Hydride transfer is an important reaction for chemistry (e.g., fuel cells), as well as biology (e.g., respiratory chain and photosynthesis).
More Hydrogen News and Hydrogen Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

In & Out Of Love
We think of love as a mysterious, unknowable force. Something that happens to us. But what if we could control it? This hour, TED speakers on whether we can decide to fall in — and out of — love. Guests include writer Mandy Len Catron, biological anthropologist Helen Fisher, musician Dessa, One Love CEO Katie Hood, and psychologist Guy Winch.
Now Playing: Science for the People

#543 Give a Nerd a Gift
Yup, you guessed it... it's Science for the People's annual holiday episode that helps you figure out what sciency books and gifts to get that special nerd on your list. Or maybe you're looking to build up your reading list for the holiday break and a geeky Christmas sweater to wear to an upcoming party. Returning are pop-science power-readers John Dupuis and Joanne Manaster to dish on the best science books they read this past year. And Rachelle Saunders and Bethany Brookshire squee in delight over some truly delightful science-themed non-book objects for those whose bookshelves are already full. Since...
Now Playing: Radiolab

An Announcement from Radiolab