Posted on 11/27/2014 12:46:55 AM PST by 2ndDivisionVet
A weak spot found in otherwise ultra-strong graphene -- the thinnest, strongest and least permeable material known to science -- could in fact be a boon and could lead to a revolution in fuel cell technology, researchers say.
Research at Britain's Manchester University led by Andre Geim -- who shared a Nobel Prize for the discovery of graphene -- has shown that the material is not quite as impermeable as previously though and will, in fact, allow protons to easily pass through it.
This quality could be utilized in the future to create graphene membranes that could "sieve" hydrogen gas directly out of the air to be used to generate electricity, the researchers say.
"We are very excited about this result because it opens a whole new area of promising applications for graphene in clean energy harvesting and hydrogen-based technologies," says a co-researcher in Geim's study, Marcelo Lozada-Hidalgo.
Graphene, at a carbon atom thick, is 200 times as strong weight-for-weight as steel.
Its impermeability to atoms of any gas or liquid has made it a candidate for use in impermeable packaging and corrosion-proof coating.
Although even the smallest atoms cannot pass through graphene, Geim and his researchers suspected that protons -- hydrogen atoms that have been stripped of their electrons -- might find a way through.
Confirming that they could in fact do so means graphene could be used as proton-conducting membranes, considered a vital component in developing fuel cells, the researchers said in a report of their study published in the journal Nature.
Fuel cells and other hydrogen-based technologies require a barrier that only allow hydrogen protons to pass through, they point out.
A significant problem with existing fuel cells is that the fuels that allow them to convert chemical energy into electricity leak across their membranes, reducing the cell's efficiency by "poisoning" the chemical processes -- something the researchers say can be solved using graphene.
"When you know how it should work, it is a very simple setup," Lozada-Hidalgo says. "You put a hydrogen-containing gas on one side, apply small electric current and collect pure hydrogen on the other side. This hydrogen can then be burned in a fuel cell."
Although the scientists worked with very small membranes yielding tiny flows of hydrogen, the technology to make large graphene sheets exists, notes researcher Sheng Hu.
"Because graphene can be produced these days in square meter sheets, we hope that it will find its way to commercial fuel cells sooner rather than later," Hu says.
Seems like this may work better in ultra pure water rather than air.
Disassociation of hydrogen ions from water happens in pure water naturally.
This would make free hydrogen available for the graphene to pickup.
“Fuel cells and other hydrogen-based technologies require a barrier that only allow hydrogen protons to pass through, they point out.”
Weakly written... A proton is a proton. There’s no difference between a hydrogen proton and any other proton.
And furthermore, there are a lot of membranes that H2 will go through... Not just the proton, but the molecule with two protons and two electrons.
Palladium comes to mind...
True, but hydrogen is the only element that is a single proton. Strip the electron, and you have a very small item indeed.
well, since water vapor is a much more powerful ‘greenhouse gas’, and since burning hydrogen produces water vapor as the main by-product, look for the democrip regime to ban this technology as soon as their retarded regulators/czars are taught the particulars.
“True, but hydrogen is the only element that is a single proton.”
And that is true, BUT, Hydrogen is diatomic. Atomic hydrogen (h1) is extremely rare. So rare that you might say that it doesn’t exist in nature.
Lightning strikes can make it, but even then it’s short lived.
Hydrogen exists on earth as H2 which is a molecule not an atom. H2, BTW is significantly larger than the helium atom even though it’s weight is less.
Helium will defuse through a membrane at a rate orders of magnitude faster than H2.
A proton going through a membrane very easily because of it’s size even though it’s mass is only slightly less than atomic hydrogen. But the big factor in that regard is that the proton isn’t restricted by Dalton’s law of partial pressures. (which would be the key to this scheme being of any value at all)
But were still left with the lack oh H1 in the atmosphere and the fact that it takes a lot of energy to make it.
I’m thinking hey this would be great if you could just gather hydrogen out of air or water byo really tiny osmosis. It would be a net energy positive way of producing hydrogen compared to say electrolysis.
The significance of collecting hydrodgen in net positive energy way would not be just a little litte thing. It would be a big big big thing.
But cripy. I have don’t have the sort of scientific background it takes to evaluate this discovery with my own tools.
Except to say that the guy who announces this finding is also the guy who discovered the material in the first place. So its reasonable to think that he knows what he’s talking about.
Are either of you guys sufficiently comfortable with the science behind this to evaluate whether this is discovery is a significant advance. Or is this one of those things that is incremental and maybe another 15 or 20 years out when scientist have all their ducks in a row—something will come of it.
There is an abundance of hydrogen to be sure on this planet. However almost all of it has already been oxidized and exists along with oxygen in the form of water.
It’s kind of like the folks that want to split water into hydrogen and oxygen and use it for a fuel. Of course do this very easily, but not without putting in more energy than burning it would yield. The only way to reduce it in a net positive way energy wise, would be with magic.
It’s even worse for atomic hydrogen... First you’ve got to get the hydrogen in the form of H2, then you have to reduce it further to H1 by adding even more energy.
That’s not to say that graphene wouldn’t be useful as a membrane in a fuel cell, it very well might, but your not going to get hydrogen in any useful amounts out of the air with it. There just isn’t enough H2 in the air to begin with, and there’s almost no H1.
First you’ve got to get the hydrogen in the form of H2, then you have to reduce it further to H1 by adding even more energy.
.......................
So there would have to be a large membrane surface area—something like a big house sized dome with a concave side into the wind— and plenty of wind to collect hydrogen passively in any quantities from the atmosphere. (Presumably that would not cost any energy except for the cost of building and maintaining the structure.)
However, the downside here is that the hydrogen you collect would be in the form of H2. Because almost all the hydrogen in the atmosphere is in the form of H2. Is that correct. To burn the hydrogen you’d need to convert it to H1. Is that correct?
The article does say that the membranes are small enough to allow only one proton through. That would be H1.
How much energy does it take to convert H2 to H1. Byo comparison I think electrolysis gives you something like .4 cents worth of power for every dollar you put in.
The atmosphere is only about 50 parts per million H2 by volume. It would take a real large membrane to get anything interesting at all (and then not very interesting). So if you had a 200,000 square foot membrane you would get a cubic foot of hydrogen (that would be on the high side since most of the 200,000 cubic feet of air wouldn’t be in contact with the membrane) and that would be at standard pressure 14.7 psi.
Of course the hydrogen in the air is H2, so you’d probably get none. You could get a membrane that H2 would go through but then you have to deal with the partial pressure problem. Helium for instance will pass through the rubber in a balloon. That’s why the balloon no longer floats after a while. A Helium atom is much smaller than a H2 molecule and roughly the same size (just a little bit bigger) than a H1 atom.
I think the person who wrote the article (not the scientists) made some stuff up...
Not a scientist. I'd say it's most likely an incremental advance. Of course, everything helps.
As babygene said earlier, water is the most abundant source of hydrogen, but it takes a fair amount of energy to crack it. You can do it with solar, but with anything solar (PV), you're looking at another incremental thing, because of efficientcy issues.
Of course, if you add up a bunch of incremental things, someday you've got something that is pretty revolutionary considering where you started. I'm sure folks will find lots of uses over time for graphene, which has really only been around in a material sense since fairly recently. It's just too cool a material not to at least look at potential applications.
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