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Energy

Rust and light combine for a 25x boost in hydrogen production

By Loz Blain
February 27, 2020
Rust and light combine for a 25x boost in hydrogen production
A Japanese team has figured out a much more efficient way to photocatalyze the splitting of water molecules into hydrogen and oxygen using a common form of rust
A Japanese team has figured out a much more efficient way to photocatalyze the splitting of water molecules into hydrogen and oxygen using a common form of rust
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A Japanese team has figured out a much more efficient way to photocatalyze the splitting of water molecules into hydrogen and oxygen using a common form of rust
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A Japanese team has figured out a much more efficient way to photocatalyze the splitting of water molecules into hydrogen and oxygen using a common form of rust

Scientists at the Tokyo University of Science have used rust as a catalyst in light-assisted hydrogen production from organic waste, finding it produces 25 times more hydrogen than previous titanium dioxide catalysts.

Japan and Korea, in particular, see hydrogen as the clean fuel of the future, and are reorganizing themselves to make way for a zero-emissions "hydrogen economy" in which transport will mainly be driven by fuel cell vehicles and hydrogen-burning engines, which emit only water as their end product.

Economical and sustainable hydrogen production methods, however, have not really been nailed down. Electrolysis wastes a lot of energy and uses up fresh water. Gas or coal production releases large amounts of carbon at the production site, negating any perceived environmental benefits. Solar-driven photocatalytic processes invented in the 1970s produce so little hydrogen they're not worth the trouble or expense of their titanium dioxide catalysts.

Now, a team from the Tokyo University of Science believes it's found a solution for cheap, highly efficient photocatalytic hydrogen production based on a special type of rust.

Using the light from a mercury/xenon lamp, a water-methanol solution and a form of rust called α-FeOOH as the catalyst, the team found themselves producing 25 times more hydrogen than previous titanium dioxide techniques. As an added benefit, something about this particular form of rust seems to help stop the hydrogen gas from re-coupling with the oxygen in the container, allowing easier separation and heading off a potentially explosive hazard. The configuration continued producing hydrogen in a stable fashion for more than 400 hours.

The team next plans to study exactly what role oxygen plays in activating light-induced α-FeOOH reactions, because it stopped working altogether when the oxygen was removed from the reaction chamber. While this technique still requires the splitting of water – far from an infinite resource – to create hydrogen, it could be an efficient way of doing so using sunlight without requiring any expensive catalysts.

The study was published in Chemistry: A European Journal.

Source: Tokyo University of Science

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11 comments
Loz Blain
Loz Blain
Loz has been one of our most versatile contributors since 2007, and has since proven himself as a photographer, videographer, presenter, producer and podcast engineer, as well as a senior features writer. Joining the team as a motorcycle specialist, he's covered just about everything for New Atlas, concentrating lately on clean energy, AI, humanoid robotics, next-gen aircraft, and the odd bit of music and automotive. In February 2024, he stepped up to lead New Atlas as Editorial Director, and he's as curious as anyone to see how that pans out.

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11 comments
Mzungu_Mkubwa
If this technique could use seawater (rather than the "water-methanol solution") and sunlight (rather than the "light from a mercury/xenon lamp") as its primary inputs, then it could have real potential. Place a scaled-up reactor near the shoreline and use it to generate both electricity and fresh water from solar power! Pipe dream?
Douglas Rogers
Distillation energy is negligible compared to hydrogen reaction energy so fresh or salt water is irrelevant. Even fresh water has hundreds of times the availability of fuel.
bwana4swahili
"While this technique still requires the splitting of water – far from an infinite resource – to create hydrogen" Not too sure about the "far from an infinite resource" comment? Water is pretty common on Earth!!
Expanded Viewpoint
Soooo, which is it then, a common form of rust, or a special type of rust? Maybe a special common form of rust? How is it made? Are any expensive catalysts or processes used to make it?
How much energy is used to power the artificial light that is needed for this increased rate of reaction to take place? What is the cost of that portion of the system? What is the rate of amortization of it? Or do all of those extra things come cheaply because they all grow on trees found in Nature?

Randy
Grunchy
25x negligible could still be negligible, this story tells nowhere near enough information.
Hydrogen remains a diatomic gas which is both highly explosive and extremely difficult to seal, being the smallest molecule in existence. The tank has to be extremely high performance, holding thousands of PSI, as compared to tires which only hold about 30 psi. The problem of acetylene was solved by dissolving it in acetone and stabilizing it in a porous structure, but there is still no equivalent safe storage method for hydrogen. Plus no matter what you can't get past the potential of hydrogen to be misused as a bomb. I think ethanol still makes more sense, it's produced sustainably (no net contribution to atmospheric CO2) and burns with high equivalent octane and the resultant combustion is very gentle on internal combustion engines.
christopher
"water – far from an infinite resource" - what planet do you live on?
ljaques
I'm with christopher in being wary about all these million new taps sucking up the ocean. Desalination and H plants would both be salting the waters. What's a fish to do? The only people who'd like that are those who think the sea level is going to rise 39 feet this century, but they might be busy screaming about the amount of H leaked into the atmo, creating more AGWK!
meofbillions
Grunchy, it's my impression that hydrogen storage tanks can contain metal hydride salts, which hydrogen dissolves in, reducing the storage pressure..

I also agree with Expanded Viewpoint that this is a very poorly written article, and it makes me wonder about New Atlas.
nick101
Having worked on the 'hydrogen highway' (that wasn't) I find the occasional, true, claim or observation in these comments. Some are comical, (no, you can't use hydrogen to build an H-bomb without an A-bomb to ignite it!) hydrogens day will come, eventually, when everything else is gone.
Catweazle
"While this technique still requires the splitting of water – far from an infinite resource" --- Last time I looked, around three quarters of the planet's surface was covered in it to a depth of several kilometres. Added to which, when it's burned it goes back to being water again, so I don't quite understand the relevance of that comment!
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