The technique of these researchers at the University of California, Santa Cruz (UCSC) involves aluminum nanoparticles that remove oxygen from water molecules to produce hydrogen gas.
Relatively simple, this process makes it possible to generate large quantities of hydrogen at room temperature. It thus solves one of the most important problems related to the production of hydrogen: the large amounts of energy required for its production.
“This solution, which works with any type of water, including wastewater and seawater, does not require any energy input to produce hydrogen”says Scott Oliver, professor of chemistry at UCSC. “We’ve never seen anything like it!”
A unique process
The key to the process is to use metallic gallium to induce a continuous reaction with water. This reaction”aluminum-gallium-water” has been known for decades, but the group of researchers have greatly improved it. Using scanning electron microscopes and X-ray diffraction techniques, scientists have been able to develop the best mixture of aluminum and gallium in order to efficiently generate hydrogen: the composite “gallium-aluminum 3:1“. The alloy with a high gallium content eliminates the layer of aluminum oxide that normally blocks the reaction with water and generates aluminum nanoparticles which accelerate this reaction.
“Gallium separates nanoparticles and prevents their aggregation into larger particles“says Bakthan Singaram, professor of organic chemistry at UCSC.”These aluminum nanoparticles, which are usually complex to produce, are generated here at room temperature and under normal atmospheric pressure.”
According to the researchers, if immersed in cyclohexane to preserve it from humidity, the composite material can be stored for at least 90 days.
The availability of aluminum is much greater than that of gallium. The first can come from post-consumer materials such as cans or aluminum foil. Gallium is more expensive and less abundant, but the method developed by the UCSC allows it to be reused many times without any loss of efficiency.
“We still have work ahead of us…”, conclude the scientists. “We need to ensure that this technique can be applied on an industrial scale. Nevertheless, the first tests show that it has great potential for the production of large quantities of hydrogen.”