Scientists Find a Simple Way to Produce Hydrogen From Water at Room Temperature

Scientists Find a Simple Way to Produce Hydrogen From Water at Room Temperature

Hydrogen fuel promises to be a clean and abundant source of energy in the future, as long as scientists can find ways to produce it conveniently and economically and without fossil fuels.

A new study gives us another promising step in that direction, provided existing supplies of aluminum and post-consumer gallium can be used.

In the new research, the scientists describe a relatively simple method involving aluminum nanoparticles that can strip oxygen from water molecules and leave hydrogen gas.

The process produces large amounts of hydrogen and all works at room temperature.

This removes one of the big obstacles to the production of hydrogen fuel: the large amount of energy needed to produce it using existing methods.

This technique also works with any type of water, including wastewater and ocean water.

“We don’t need any energy input, and it bubbles hydrogen like crazy,” says materials scientist Scott Oliver from the University of California, Santa Cruz (UCSC).

“I’ve never seen anything like it.”

Key to the process is the use of gallium metal to allow continuous reaction with water. This aluminum-gallium-water reaction has been known for decades, but here the team has optimized and improved it in a few special ways.
Using scanning electron microscopy and X-ray diffraction techniques, researchers were able to find the best mixture of aluminum and gallium to produce hydrogen with the greatest efficiency: a 3:1 gallium-aluminum composite.

The gallium-rich alloy does double duty in both removing aluminum’s oxide coating (which would ordinarily block the reaction with water) and in producing the aluminum nanoparticles that enable faster reactions.

“The gallium separates the nanoparticles and keeps them from aggregating into larger particles,” says Bakthan Singaram, a professor of organic chemistry at UCSC.

“People have struggled to make aluminum nanoparticles, and here we are producing them under normal atmospheric pressure and room temperature conditions.”

The mixing method is not complicated, the researchers report, and the composite material can be stored for at least three months if immersed in cyclohexane to protect it from moisture, which would otherwise degrade its effectiveness.

Aluminum is easier to obtain than gallium because it can come from post-consumer materials, such as discarded aluminum cans and aluminum foil.

Gallium is more expensive and less abundant, but in this process at least it can be recovered and reused many times without losing its effectiveness.

There is still work to be done, not least to make sure this can be scaled from a lab setup to something that can be used on an industrial scale. However, early signs indicate that this is another method that has a lot of potential for hydrogen fuel production.

“Overall, the Ga-rich Ga−Al [gallium-rich gallium-aluminum] mixture produces substantial amounts of hydrogen at room temperature with no energy input, material manipulation, or pH modification,” the researchers conclude in their paper.

The research has been published in Applied Nano Materials.