Researchers have created a solar-powered device that produces hydrogen fuel directly from moisture in the air. They say their prototype produces more than 99% pure hydrogen and runs in dry air with a relative humidity of 4%.
According to its inventors, the prototype produces hydrogen with a purity of over 99% and can work in dry air with a relative humidity of 4%. The device would make it possible to produce carbon-free hydrogen, even in regions where water on land is scarce, they say.
Hydrogen is a carbon-free fuel that only produces water as a by-product when burned. However, pure hydrogen is not abundant in nature and its production requires an energy input. Large-scale production usually involves fossil fuels that generate carbon emissions.
The study’s lead author and senior professor of chemical engineering at the University of Melbourne, Dr. Gang Kevin Li said the hydrogen-producing device can be powered by solar or wind power.
first test
A prototype produced hydrogen for more than 12 consecutive days in a supervised test. “For one of them, we only let it run for eight months,” Li said.
The device is made of a spongy material with a hygroscopic liquid, a fluid that absorbs moisture from the air, with a function similar to silica gel bags. The absorbed water molecules then split at the electrodes into hydrogen and oxygen gases, a process known as electrolysis.
“Hydrogen is the best clean energy… as long as it has renewable energy sources to electrolyze water,” Li said.
The device is estimated to produce up to 93 liters of hydrogen per square meter per hour. “If you have 10 square meters of this unit, you can power an entire house… to replace your home’s consumption of natural gas for cooking and heating,” Li said.
Prototypes are still small, and the team has plans to create 1-square-meter and 10-square-meter units next year.
Hydrogen fuel, useful but not economizer
The researchers predict that the device could be a useful tool in regions where liquid water is not available to produce hydrogen. “Large parts of the world have water scarcity problems,” Li said. “When you have a lot of renewable energy, wind or solar, [a menudo] you don’t have a lot of fresh water for that kind of hydrogen production.”
Kim Beasy of the Victorian Hydrogen Center at Swinburne University, who was not involved in the research, said that hydrogen fuel, while important, is not a panacea for reaching net zero. “We’re starting to understand that hydrogen will be a piece of the puzzle,” he said.
“This will give us a direction to get out of some industries that are very difficult to mitigate, like transportation. We have no alternative to diesel at the moment… hydrogen is a very good option.”
The necessary economies of scale “would probably not be achieved immediately with clean hydrogen,” Beasy said, citing the high price of conventional hydrogen electrolyzers. “What we really need is more government support and subsidies to lower the cost of getting this technology up and running.”
The study was published in the journal Nature Communications .
By Donna Lu. Article in English