Scientists found a new way of cost-effective electrolysis that can turn seawater into hydrogen fuel, an alternative to fossil fuels.
Stanford University scientists have experimented on generating hydrogen fuel through the use of solar power, electrodes, and seawater from San Francisco Bay.
Hydrogen fuel from purified water is costly to produce so the team led by Hongjie Dai, a chemistry professor in Stanford's School of Humanities and Sciences, developed a prototype device that can definitely separate hydrogen and oxygen from saltwater without corroding the device used for water-splitting.
The hydrogen generated from this process can be turned into fuel cells to power electric vehicles. This process also creates breathable oxygen for divers.
Hydrogen fuel is an attractive alternative to fossil fuels because it doesn't emit carbon dioxide that worsens climate change. If this discovery turns out well and allows transfer of technology, then the vast oceans and saltwater in the planet could become infinite sources of renewable energy.
Non-Corrosive Electrolysis Device
The water-splitting device is basically two electrodes submerged in water and connected to an electric power source. When electricity is turned on, hydrogen gas is emitted out of the cathode or the negative side. The opposite side called anode produces breathable oxygen.
However, the high concentration of chloride in saltwater can easily corrode or wreck the positive end with an anode. Corrosion resulting from the electrolysis process limits the usage and the lifespan of the water-splitting device.
To slow down the corrosion of the anode submerged in saltwater, the scientists coated the anode with layers of negatively charged particles. Layers of nickel both serve as a protection for the metals and as a repellant to chloride.
The core conductor made of nickel foam was layered with nickel sulfide and nickel-iron hydroxide on top of each other. The nickel sulfide creates a negatively charged layer during electrolysis and prevents chloride from reaching the core metal.
"The whole electrode falls apart into a crumble but with this layer, it is able to go more than a thousand hours," said Michael Kenney, co-lead author of the paper.
Using the multi-layer prototype device that repels chloride, the scientists were able to produce 10 times more electricity during controlled experiments conducted inside a laboratory. The lifespan of the electrolysis machine was increased from 12 hours to 1,000 hours.
"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.
The team also designed a solar-powered device that ran electrolysis in seawater from San Francisco Bay. The technology that they used matches the current water-splitting devices that use purified water.
Through this process, submarines can create breathable oxygen without having to surface for air.
The study is published in the journal Proceedings of the Natural Academy of Sciences.