Liquid Sponges Extract Hydrogen From Water

New submitter gaelfx writes: Researchers at Glasglow University have an interesting method for separating the hydrogen out of water: Liquid Sponges. Most methods of extracting the hydrogen involve some form electrolysis, but these generally require some pretty expensive materials. The researchers claim that they can accomplish this using less electricity, cheaper materials and 30 times faster to boot. With both Honda and Toyota promising hydrogen fuel cell cars in Japan within the next few years (other manufacturers must be considering it as well, if not as publicly), does this spell a new future for transportation technology?

Comments

Electrolysis still required, says TFA

[brambus]

The process uses a liquid that allows the hydrogen to be locked up in a liquid-based inorganic fuel. By using a liquid sponge known as a redox mediator that can soak up electrons and acid we’ve been able to create a system where hydrogen can be produced in a separate chamber without any additional energy input after the electrolysis of water takes place.

Re:Electrolysis still required, says TFA

[brambus]

It's still an interesting article. It seems they've found a way of cheaply producing ammonia from hydrogen. Not sure they meant ammonia exactly, but they mention "liquid-based inorganic fuel" and later talk about how ammonia is important for fertilizer, so I'm kinda guessing that's what they're making. Ammonia can then be used to either make fertilizer, liquid fuel substitutes and a bunch of other interesting processes.

Re:Nature

[gstoddart]

Call me a cynic, but wouldn't nature of done

Call me a cynic, but shouldn't you have learned the difference between "of" and "have" by now?

The contraction " 've" (should've) is not the same as "of", and never has been.

*sigh* My grade school English teacher would be laughing at me right now. Now get off my damned lawn!!

Another Summary: Scheduling hydrogen release...

[Anonymous Coward]

I've found this difficult to understand what has been accomplished, and I found this other summary helpful. From sciencemag.org:

Scheduling hydrogen release from water

Photosynthesis splits water to provide protons and electrons for plant growth; oxygen is a by-product. When chemists split water, they're also more interested in making fuel, and the simplest product is hydrogen (a combination of protons and electrons). One challenge is keeping the reactive hydrogen and oxygen product streams separate. Rausch et al. present a scheme that captures the protons and electrons in a molecular cluster of silico-tungstic acid. Later, they expose the cluster to platinum, coaxing the acid into releasing hydrogen. Eliminating the mixing risk increases the potential for household use.

Re:This ignores the big problem of hydrogen, leaka

[Anonymous Coward]

This discovery allows the hydrogen to be stored and created at regular atmospheric pressure, since it is stored as a liquid acid. So at least during storage and production, I think this discovery solves that.

Re:Nature

[BringsApples]

First of all your grammar just made me twitch a little bit. Replace "of" with "have", and please do it forever.

Second, Nature knows what it's doing, it's man that's got shit backwards. Nature is was able to extract the energy from oxygen, rather than hydrogen. The current biological configuration is acting on levels higher than simple materialism can afford. No need to propel biology with explosions of the type produced by hydrogen. See here for a (very basic) comparison of oxygen vs hydrogen.

What they actually accomplished

[Required Snark]

This is from the Science article summery.

The electrolysis of water using renewable energy inputs is being actively pursued as a route to sustainable hydrogen production. Here we introduce a recyclable redox mediator (silicotungstic acid) that enables the coupling of low-pressure production of oxygen via water oxidation to a separate, catalytic hydrogen production step outside the electrolyzer that requires no post-electrolysis energy input. This approach sidesteps the production of high-pressure gases inside the electrolytic cell (a major cause of membrane degradation) and essentially eliminates the hazardous issue of product gas crossover at the low current densities that characterize renewables-driven water-splitting devices. We demonstrated that a platinum-catalyzed system can produce pure hydrogen over 30 times faster than state-of-the-art proton exchange membrane electrolyzers at equivalent platinum loading.

Or in even simpler terms

Photosynthesis splits water to provide protons and electrons for plant growth; oxygen is a by-product. When chemists split water, they're also more interested in making fuel, and the simplest product is hydrogen (a combination of protons and electrons). One challenge is keeping the reactive hydrogen and oxygen product streams separate. Rausch et al. present a scheme that captures the protons and electrons in a molecular cluster of silico-tungstic acid. Later, they expose the cluster to platinum, coaxing the acid into releasing hydrogen. Eliminating the mixing risk increases the potential for household use.

Note that platinum is still required, but it works 30 times more efficiently. Also the pressure needed is much lower.

Re: Nature

[Anonymous Coward]

Promulgating the Hindenburg myth. The gas bag itself was flammable; it wouldn't have mattered what gas was in it, when it disintegrated. The burning of the released hydrogen gas caused none if the damage; it went up, and the specific heat was low. It was gone in a moment. The fire you see in the video is burning diesel fuel and oil.

Re:Is the expense of electrolysis the main inhibit

[radtea]

The next generation of attempts stores the hydrogen chemically.

I'm not sure if it qualifies as "the next generation" when it has been studied since well before my now-adult children were born.

Skepticism with respect to hydrogen exists in part because some of us have heard this tune before. Storage of hydrogen in metal sponges is nothing new, and they have some very nice theoretical properties, including reasonable volumetric energy density, which is a big problem for hydrogen.

Getting up to 1/5 the volumetric density of fossil fuels--which is the likely upper limit--would make hydrogen cars more than competitive with electric vehicles. But so far no one has managed that, despite continuous work on the problem.

For some reason TFA doesn't say anything about the long history of storing hydrogen in metal sponges, or make clear what makes this one different, although one can guess that as a liquid there are likely metal particles in suspension and that gives a huge surface area advantage.

It's almost as if the articles were written by junior staff members with no actual knowledge of hydrogen storage technology, but since we live in a "knowledge based economy" where STEM skills are in incredibly high demand there is no way reputable news organizations like the BBC would do anything like that, right?

Re:No, not really

[jdschulteis]

You still need very pure water or you poison the process. Where's that water coming from? How do you collect the gaseous hydrogen? You still need to liquify it and all the emrittlement and cryogenic issues are still there.

Even if hydrogen gas is free, it makes no sense as an energy carrier for cars.

They don't collect the gaseous hydrogen in the electrolyzer; they soak it up with a "liquid sponge" ("a recyclable redox mediator (silicotungstic acid) " according to the article's abstract. In principle at least, hydrogen could be stored and transported in this form (a liquid sponge soaked with hydrogen).; the hydrogen can be catalytically released (wrung out of the liquid sponge) when needed. Whether such a system could be built with a practical size, weight, and cost for use in vehicles is another matter.

Re:Is the expense of electrolysis the main inhibit

[Solandri]

am interpreting your first question as "Is the expense of electrolysis the main inhibitor of a hydrogen-fuel economy?" I believe the answer is "sorta, but not really." The cheapest way to get hydrogen is from natural gas. The problem is that the whole reason to move to a hydrogen economy is to become carbon-neutral. If you use natural gas mines, you defeated the purpose.

Not really. Natural gas is methane - CH4. It's about 35-85x more potent greenhouse gas than CO2. If you're converting methane to hydrogen, then converting that to CO2, you're not reducing the amount of carbon in the atmosphere, but you're still helping reduce the greenhouse effect.

All this is of course contingent on what would have happened to the methane if you weren't using it as fuel. Methane is primarily a byproduct of oil drilling. Until recently energy prices were low enough that it wasn't cost-effective to capture it, so oil companies just burned it as it came up the wells (those fires you see on top of long poles at oil fields). So since it was going to be converted to CO2 anyway, converting it to hydrogen to be used in fuel cells is actually carbon neutral. If oil production drops enough that we need to drill for methane specifically to keep up production, then it starts being carbon positive.