This may well be a very important and interesting discovery but I cringed a few times at the poor explanation of some of the science.
Example: "a million times thinner than human hair, yet more than 200 times stronger than steel" the word "yet" suggests that it is very strong in an absolute sense despite being so thin. Yet in reality the comparison is to an atom-thick sheet of steel, which is not very strong at all. This strength doesn't easily scale, as evidenced by the fact that graphite (lots of graphene layers) is not 200 times stronger that steel. (note that my explanation of the science may not be perfect but it is better than this article)
> This strength doesn't easily scale, as evidenced by the fact that graphite (lots of graphene layers) is not 200 times stronger that steel.
This is an even worse explanation of the science. On the level of saying that the strength of steel doesn't scale because I can bend pig iron with my hands.
Materials-science articles about a modest advance in surface chemistry (which is usually called "nanotechnology") are regularly being hyped into "big commercial breakthrough real soon now" articles. Nature and MIT Technology Review (which, despite the name, is a commercial company) are the big offenders. Super-battery or fuel cell articles appear frequently, but never seem to result in actual products.
Hydrogen isn't an "energy source", anyway. You have to crack it out of water or pull it out of hydrocarbons. Those processes are uphill energetically. At best, hydrogen is a storage medium.
I agree with your assessment of the materials science articles but in this case I think you missed the 'breakthrough' part.
Graphene allows positively charged hydrogen to pass through it. The thought experiment is you create a vessel with an inner porous core, you wrap it in graphene, and then you apply a vacuum. That device will pull any positively charged hydrogen out of the atmosphere (which frankly isn't much except during thunderstorms)
This behavior with graphene isn't unknown, the first example was noting that graphene made for an exceptional water filter [1].
Even if that works, it may be subject to all the usual problems, such as filter clog. This is a big problem with hydrogen fuel cells, which require extremely pure hydrogen. It's a general problem with materials whose carefully constructed surface structure has some unusual property. The surface structure may be fragile.
A good example is NeverWet, the ultrahydrophobic coating. It repels water because the surface is composed of tiny spikes, and water's surface tension keeps the water supported on the surface of the spikes. This works so well that mud will run off of shoes treated with it. The effect, though, doesn't last long; even slight wear on the surface damages the micro-spikes. Reviews of the product on Amazon agree: great at first, useless within hours to days of use: (http://www.amazon.com/Oleum-274232-Never-Multi-Purpose/produ...).
> Ten Angstroms is equivalent to a billionth of a metre.
I love completely misleading explanations for the laymen. And I bet they'd get a much more impressive figure if they comapared the ten Angstrons with a light year.
The important detail here is that ten Angstrons is several times bigger than sodium and chloride ions. The researchers want a filter that allows for desalination, but all they got is one that allows for purification.
As a tiny fix: Tech review is a separate, non-profit company, but it's owned by MIT -- to the point where the version delivered (freely) to alums has an extra section for alum news. But yes - it's a little breathless about the OMG amazing discovery ... that turns out to not quite make it. :)
"Find a material with novel properties and then search out uses for it". For most industries, this is cart before the horse, but for the Materials Science industry, they have made a living out of it for well over a century. It is the reason why you can buy sandpaper, carwash soap, sticky notes, and bullet-proof vests from the same company (in this example, 3M, but there are dozens of successful Materials Science megacorps).
When you see stuff like this coming out of Academia, it is usually no different than the bajillions of articles out there about some novel new way to fight cancer. Someone found something interesting, and they are trying to sell the IP.
The article goes on about the idea of collecting hydrogen from the atmosphere using a graphene filter. There is no appreciable amount of hydrogen in the atmosphere.
Using air humidity? Say we have 10 grams of water per cubic meter of air (so about 1% of the total air mass), so about 1 gram of hydrogen.
At about 140 kJ/kg, and assuming a 10% reduction efficiency, and 100 watts per square meter solar panel, it should be able to reduce 0,071 grams per second or 260 grams per hour.
Assuming 10% of air moisture can be extracted, the wind passing through the system to keep the water flow would need to be about 0,7 m/s. It's almost always as windy as that.
... and some way to store and transport hydrogen. We can make hydrogen quite cheaply right now (it is kindergarten technology), but once you try to store and/or transport it then this is where things get really, really difficult [1].
No, I assumed (in hindsight could have mentioned it) that you could use the hydrogen locally to generate electricity. The thing is connected to the the electricity network.
But I realized that is roughly the momentary day power of the panel. The real yearly average production is maybe 15% of that.
Example: "a million times thinner than human hair, yet more than 200 times stronger than steel" the word "yet" suggests that it is very strong in an absolute sense despite being so thin. Yet in reality the comparison is to an atom-thick sheet of steel, which is not very strong at all. This strength doesn't easily scale, as evidenced by the fact that graphite (lots of graphene layers) is not 200 times stronger that steel. (note that my explanation of the science may not be perfect but it is better than this article)