Even the scientists were surprised by their finding: “Without the need to add power, hydrogen began to bubble. I’ve never seen anything like it,” says Scott Oliver, a UCSC professor. He talks about a new powder of aluminum and gallium nanoparticles that generates hydrogen when placed in water, even seawater.
Magic? More like chemistry. Aluminum oxidizes rapidly in water, removing oxygen from H2O and releasing hydrogen. It is a reaction that lasts very little, since a very thin layer of aluminum oxide seals it and ends the party. Could you continue with the fun? That’s why the UC Santa Cruz researchers used gallium, adding gallium (it’s been known for a long time that it removes the aluminum oxide layer and keeps the aluminum in contact with water, but with limited effect).
It was a student, Isai López, who was playing to produce hydrogen with aluminium/gallium… in the kitchen of his house. Biochemistry professor Bakthan Singaram added a little more rigor by adding a student who was doing his thesis. And when they tested mixtures high in gallium, hydrogen production skyrocketed.
After various tests, they saw that the combination of three parts of gallium with one part of aluminum was the most effective. In addition to dissolving the aluminum oxide, it made the aluminum separate into nanoparticles, which were kept separate. It sounds easy, but for a long time people had been trying to create aluminum nanoparticles, and suddenly they were successful under normal conditions of atmospheric pressure and room temperature. By separating the aluminum so much, they managed to extract 90% of the theoretical maximum amount: with a single gram of their gallium and aluminum alloy, 130 ml of hydrogen would be quickly released when placed in water.
Reading the study, there is another surprise: the water does not need to be clean. They range from sewage to seawater. Isn’t there a problem? You are right. Gallium is expensive. But the researchers say it could be fully recovered at the end of the process and used with new aluminum to create more hydrogen.
Now the team has applied for a patent on the process and is looking at how it could scale it commercially. The idea is to create hydrogen storage powder (yes, like EAT’s Si+) to make it easier to store and transport, which is expensive to compress into gas. There is still time for that, but being able to use seawater to carry out this chemical reaction, at ambient temperatures and pressures, gives it a key differentiating point.
Via: ACS Nano Materials
Source: UC Santa Cruz
