Hydrogen is one of the potential fuels of the future. But before it can be considered a clean energy source, it must be produced in an environmentally friendly way. In recent years, research aimed at improving this concept has multiplied. Recently, scientists from the University of California at Santa Cruz (UCSC) say they have discovered a method that promises to be less expensive and more environmentally friendly to extract hydrogen from water. To achieve this, they used a composite rich in aluminum and gallium.
Gallium at the center of the process
At the base of this new turning point in green fuel there are therefore metallic gallium (Ga) and aluminum (Al). The use of gallium allows to create a continuous reaction with water. As for aluminum, it is the reagent that allows the separation of oxygen from the water molecules, releasing hydrogen gas. However, aluminum develops an aluminum oxide layer which prevents it from reacting with water. The researchers therefore had to develop a method to improve the aluminum-gallium-water reaction. For this, they used the techniques of scanning electron microscopy and X-ray diffraction. Results showed that increasing gallium concentration and reducing aluminum in the composite increased hydrogen production.
“Gallium separates the nanoparticles and prevents them from aggregating into larger particles (…) People have had problems producing aluminum nanoparticles and here we produce them under normal conditions of atmospheric pressure and room temperature.” Bakthan Singaram, professor of organic chemistry at UCSC.
Produce hydrogen without the need for electricity
In this reaction, the gallium-rich alloy therefore plays two roles: it eliminates the aluminum oxide coating and produces the aluminum nanoparticles useful for faster reactions. According to the researchers, the process generates a large amount of hydrogen. What’s even more interesting is the fact that it takes place at room temperature. According to Scott Oliver, professor at UCSC, the team did not need power during the experiments. The teacher Bactan Singapore for its part, it states that it is difficult to produce aluminum nanoparticles. However, they would have produced them under normal conditions of atmospheric pressure.
“We don’t need any energy inputs and hydrogen is bubbling like crazy (…) I’ve never seen anything like it.” Scott Oliver, scientist at the University of California, Santa Cruz (UCSC)
According to the authors of the research, this technique is quite easy to implement. The composite material can be kept for a long time provided it is immersed in cyclohexane to protect it from moisture. In addition, aluminum is a rather abundant and easy to obtain material. As for gallium, although it is relatively expensive, it is reusable. This discovery could therefore revolutionize the production of green hydrogen. Note that the details of the research were published in the ACS Applied Nano Materials journal.
“Overall, the Ga-Al blend rich in Ga [gallium riche en gallium-aluminium] produces large quantities of hydrogen at room temperature without energy input, material manipulation or pH variation. ACS Publishing