Clean fuel breakthrough – Hydrogen

Optimism and drive around the potential for practical and cheap hydrogen production continues. The potential future of hydrogen feels so tantalising considering its sheer abundance on our planet, as well as in the universe. 

Indeed, in Hydrogen: overhyped or hypercharged?, one of our resident futurists, Doug Vining, recently put down his thoughts on the future of hydrogen, noting that “the appetite for investment and for funding innovation in this space is increasing, and we could be on the brink of breakthroughs that will launch the hydrogen economy from dream into reality.”

The recent discovery by UCSC scientists certainly sounds like one of these breakthroughs; only time will tell whether it has the potential to scale and play a meaningful role in creating the reality of a hydrogen economy. 

– Futureworld

The Science Alert article by David Nield explains the UCSC scientific discovery further…

Hydrogen fuel promises to be a clean and abundant source of energy in the future – as long as scientists can figure out ways to produce it practically and cheaply, and without fossil fuels.

A new study provides us with another promising step in that direction.

Scientists have described a relatively simple method involving aluminium nanoparticles that are able to strip the oxygen from water molecules and leave hydrogen gas. The process yields large amounts of hydrogen, and it all works at room temperature, removing one of the big barriers to hydrogen fuel production: the large amounts of power required to produce it using existing methods. This technique also works with any kind of water, too, 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 enable an ongoing reaction with the water. This aluminium-gallium-water reaction has been known about for decades, but here the team optimized and enhanced it in a few particular ways.

With the help of scanning electron microscopy and x-ray diffraction techniques, the researchers were able to find the best mix of aluminium and gallium for producing hydrogen with the greatest efficiency: 3:1 in favour of gallium.

The gallium-rich alloy does double duty in both removing aluminium’s oxide coating (which would ordinarily block the reaction with water) and in producing the aluminium 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 aluminium nanoparticles, and here we are producing them under normal atmospheric pressure and room temperature conditions.”

As gallium is liquid slightly over room temperature, the mixing method isn’t complicated, and the composite material can be stored for at least three months when submerged in cyclohexane to protect it from moisture, which would otherwise degrade its efficacy.

Aluminium is a lot more abundant and easier to get hold of than gallium, as it can be sourced from recycled materials. But in this process, the gallium can be recovered and reused many times over without losing its effectiveness. That’s yet another factor in favour of the new technique.

There is still work to do, not least in making sure this can be scaled up from a lab set-up to something that can be used on an industrial scale. However, the early signs are that this is another method that has a lot of potential for hydrogen fuel production.

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

The research has been published in Applied Nano Materials.

Via Science Alert, written by David Nield 31 August 2022