

MIT’s ‘Artificial leaf’ makes fuel from sunlight - audionerd
http://web.mit.edu/newsoffice/2011/artificial-leaf-0930.html

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krosaen
Cool, also saw Professor Maldonado talk about this on "Saturday Morning
Physics":

[http://www.lsa.umich.edu/vgn-ext-
templating/v/index.jsp?vgne...](http://www.lsa.umich.edu/vgn-ext-
templating/v/index.jsp?vgnextoid=4a609c8d35bbe210VgnVCM10000055b1d38dRCRD)

video:

[http://lecb.physics.lsa.umich.edu/wl/umich/phys/satmorn/2010...](http://lecb.physics.lsa.umich.edu/wl/umich/phys/satmorn/2010/winter/20100410-umwlcd0011-103200/flash.html)

his research lab:

<http://www.umich.edu/~mgroup/research.html>

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jacobolus
Thanks, that was a really great talk for non-specialists. I’ll definitely pass
it along to family and friends.

The one bit that was sort of unconvincing was when he argued that if we create
an exponentially growing photovoltaic industry it will (implication:
indefinitely) take more energy to build than it provides. But it’s silly to
assume the exponential growth to be unbounded: the whole idea is that once we
build enough capacity, we can stop making more of the things and after a few
years we get energy coming out without so much further (energy/money)
investment. He made it sound like building photovoltaics at scale would be
overall detrimental.

Other than that though, really excellent introductory background to put papers
like this current one in context.

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antimora
Found a comparison graph of efficiency of various solar cell technologies.

[http://upload.wikimedia.org/wikipedia/commons/1/16/PVeff%28r...](http://upload.wikimedia.org/wikipedia/commons/1/16/PVeff%28rev110901%29.jpg)

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HaloZero
I wish there was an efficiency vs cost of components chart here... Gives a bit
more perspective on what technologies are just achieving better rates with
just better components.

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DenisM
2.5% to 4.7% efficiency, depending on configuration.

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antimora
Just to transfer solar energy to hydrogen, but there will be additional loss
when converting to electricity, so it's way less efficient than conventional
solar cells.

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tsotha
Assuming what you want to do is convert it back into electricity. There are a
lot of industrial processes that require hydrogen as an input.

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learc83
Hydrogen lighting as well. I've heard it's very efficient for for UV grow
lights.

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drallison
Not new news.... <http://news.ycombinator.com/item?id=2380760>
<http://news.ycombinator.com/item?id=2381709>
<http://news.ycombinator.com/item?id=1726170>

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mikexstudios
While it is not new news in the sense that the artificial leaf has been
mentioned before, this MIT press release is based off of a new Science paper
from the Nocera lab where, in contrast to the previous papers, this "leaf"
does both hydrogen and oxygen generation in the same device. So the
breakthrough here is that a tandem PV was used (to supply the necessary
voltage for splitting water) and both hydrogen and oxygen evolution catalysts
were integrated with the PV.

The previous news had early versions of the device that used only a single
junction PV. Thus, some external potential had to be applied for catalysis.
Also, the device only had the oxygen evolving catalyst and relied on a buffer
solution to supply the H+ ions. Therefore, the earlier versions of the device
could not split water by itself when dropped into water.

This new device can.

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qjz
This reminds me of Vonnegut's _Ice-nine_ , but in the inverse. Drop one in the
ocean and watch it disappear in a puff of gas.

"Science is magic that _works_." -- obligatory quote from _Cat's Cradle_

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wcoenen
Then you might be interesting in reading about this synthetic biology project
to engineer an organism that can be used to inhibit or stimulate the freezing
of water:

<http://2011.igem.org/Team:KULeuven>

<http://2011.igem.org/Team:KULeuven/Project>

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johngalt
Neat packaging for electrolysis, but I'm trying to imagine where/how this
would get used. Not as elegant once you add all the apparatus to capture and
store the hydrogen.

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baq
everywhere where you need hydrogen for electricity generation and have some
water and sunlight. combine it with a fuel cell and you've got a closed cycle,
self-sufficient, localized power generation.

looking a bit further into the future, you might have a variant of this device
produce petroleum or similar fuel for your car, with an added bonus of
reducing the amount of carbon in the atmosphere.

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Sniffnoy
Huh. This makes fuel cells seem like not a bad idea after all.

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MichaelApproved
When considering all the extra equipment that would be required to make this
work, could it really be a better solution than traditional solar cells?

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rorrr
More like "makes bomb from sunlight".

H2+O2 mixture is very unstable, and explodes violently.

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zizee
Implodes

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rorrr
It actually explodes, but then leaves vacuum and water vapor behind.

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EREFUNDO
Even if this becomes successful it will never be sustainable. What will happen
when the Sun runs out of Hydrogen to burn? (in 5 billion years) We may have to
find another star. Actually that is even less of a problem to worry about
because the Sun will start burning Helium. Once it does the pressure pushing
outwards from all the nuclear explosions (helium fusion is more efficient in
converting mass to energy) at the core will be greater than the gravity
pulling everything in, causing the star to expand into a red giant. The Earth
will receive far more energy than it really needs and burn into ashes. So
either way we are screwed!.....LOL

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pyre
I'll take a 5 billion year lifetime on my fuel supply over a couple hundred
years. Just sayin'.

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EREFUNDO
I agree. Of course I am being Facetious. With the right technology I can
imagine a future where every home has solar panels and all cars are electric.
We will use nothing but solar power to run our homes and fuel our cars. I did
the math and this is all possible.

