Researchers from Stanford University have figured out a way to create hydrogen fuel by using solar power, electrodes and saltwater from the San Francisco Bay. As reported on March 18th in Proceedings of the National Academy of Sciences, separating hydrogen and oxygen gas from seawater with the use of electricity is a new and improved method. Current methods require the use of highly-purified water which is expensive to produce and is a valuable resource.
The device can generate hydrogen fuel from seawater. (Image Credit: Stanford University, H. Dai, Yun Kuang, Michael Kenney)
In order to power cities and vehicles, you would need a large amount of hydrogen that using purified water wouldn't be imaginable, simply because there isn't a large amount of purified water available. Hydrogen is a great alternative for fuel because it doesn't emit carbon dioxide and burning hydrogen creates water and can have an improvement on climate change.
Lab tests involving a demo were successful, but researchers will let manufacturers decide how they should scale and mass produce the design. Using electrolysis is an old-fashioned and simple idea to the device. It uses a power source that connects to two electrodes submerged in water. When the power is activated, hydrogen gas comes out in bubbles on the negative end, known as the cathode and more breathable oxygen comes out of the positive end, known as the anode. However, the use of negatively charged chloride in seawater salt can have a bad effect on the anode by corroding and limiting the system's durability. Researchers at the university have been working to find ways to prevent seawater from impacting the anodes.
By covering the anodes in a special coating rich in negative charges, researchers discovered that the added coating could repel the chloride in seawater, which made the metal last longer. The coating is made of layers in nickel-iron hydroxide on top of nickel sulfide, covering a nickel foam core. The nickel foam works like a conductor by carrying electricity out from the power source and the nickel-iron hydroxide triggers the electrolysis process, separating water into hydrogen and oxygen. During the process, the nickel sulfide transforms into a negatively charged layer, covering the anode and protecting it. As both negative ends of the magnets push against each other, the negatively charged layer repels chloride and keeps it from getting in contact with the core metal.
The anode has a short lifespan without the negatively charged coating. It would work for only 12 hours in seawater, causing the electrode to fall apart completely. With the added layer, the anode is able to survive even longer, for up to a thousand hours. Studies conducted in the past to split seawater for hydrogen fuel used a small amount of electrical current due to corrosion taking place at a higher current. Researchers at the university were able to use 10 times more electricity by using the multi-layered device, helping it generate hydrogen from seawater more quickly.
Tests with the device were carried out in a controlled environment in a laboratory where they could control the amount of electricity flowing into the system. They also designed a solar powered machine that created hydrogen and oxygen gas from seawater.
New methods using this technology could also open doors in the future by increasing the availability of hydrogen fuel powered by solar or wind energy. The technology could be used more extensively beyond creating energy. Divers or submarines could take devices with them in the ocean, producing oxygen without having to reach the surface for air. The technology could also be used in current electrolyzer systems, as well and the transference of it would be pretty quick.
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