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MIT's 'Artificial Leaf' Makes Fuel From Sunlight
New submitter nfn writes "MIT has published a new paper (abstract), along with a video of a working prototype, of what they're describing as an 'Artificial Leaf' that separates water into oxygen and hydrogen using cheap, non-exotic materials. 'The artificial leaf — a silicon solar cell with different catalytic materials bonded onto its two sides — needs no external wires or control circuits to operate. Simply placed in a container of water and exposed to sunlight, it quickly begins to generate streams of bubbles: oxygen bubbles from one side and hydrogen bubbles from the other. If placed in a container that has a barrier to separate the two sides, the two streams of bubbles can be collected and stored, and used later to deliver power: for example, by feeding them into a fuel cell that combines them once again into water while delivering an electric current.' No word on the arrival of 'Artificial Salads,' or when any of their other alchemy projects will bear artificial fruit."
This was already posted on slashdot
OPEC assassins will strike and this will be nothing more than a small pile of mysterious rubble and ash in Cambridge, Massachusetts.
A feeling of having made the same mistake before: Deja Foobar
Perhaps some of these New Submitter's need to do some look-ups before trying to post new information, AKA News.
I think all this hydrogen tech is very dangerous, we will start burning hydrogen and more of it will leak and escape from the earth since it is so light and before too long we will run out of water. Oh we will have plenty of oxygen, but the oceans will dry up and all life will die except the giant sandworms... At least we will have spice.
Tsukasa: All I really want, is to be left alone...
The energy crisis is solved for the 6th or 7th time this year.
What do I know, I'm just an idiot, right?
Now they just need to do that with CO2. Release the O2 and sequester the carbon to make graphite, graphene, and/or diamond.
So, dirty water and sunlight go in, hydrogen and oxygen go out.
Then the hydrogen and oxygen go into a fuel cell, and electricity and pure water come out.
Efficiency isn't anywhere near perfect, but the benefits to a cycle that turns sunlight and dirty water into electricity and pure water are pretty obvious.
Now they just need to do that with CO2. Release the O2 and sequester the carbon to make graphite, graphene, and/or diamond.
The artificial leaf epithet would seem to be a better fit for binding up carbon and producing O2.
From the article: "The new device is not yet ready for commercial production, since systems to collect, store and use the gases remain to be developed."
Yeah, right. This would be in commercial production right now, if only there were compressors and hydrogen tanks.
The reason why this is not in production is obvious. The energy capturing efficiency (and hence cost effectiveness) of the solar cell is reduced by 75 %. (Then another 50 % will be lost if the hydrogen is converted back to electricity.)
You're talking about this slashdot entry from 5 months ago: http://hardware.slashdot.org/story/11/03/28/239212/artificial-leaf-could-provide-cheap-energy
Not exactly a dup; they link to different articles.
This one's article has a video showing the prototype in operation, which is kind of cool.
The old one's article has no video, but they basically make the same points in text.
I think you mean Texans....
Yes because texans have no interest in hydrogen production and distribution ... oh wait ... http://www.texash2coalition.com/
Things like wind and solar that have extreme peaks and valleys in their generation curve could use this (or any other means of hydrolysis) to produce a steady 24/7 stream of power. They simply need to run a small electrolysis plant and a gas compressor on the supply side, And then burn the hydrogen to run a steam turbine/generator. Yes, there is some loss of efficiency in doing it, but so what? It gives you a 24/7 smooth continuous supply.
Use these to separate hydrogen and oxygen in a covered, transparent tank, let the off-gas float up a large hill through tubes, burn/redox the hydrogen for power generation, cool the exhaust, store the water at the top of the hill, let it return to the bottom of the hill at night to smooth out energy production...
Besides the debate as to whether this is a duplicate story, electrolysis has been around since the 19th century. The only thing here is that they are using solar cells to generate the power. Seems to me like saying a Reese's Peanut Butter Cup is a new discovery because they mixed chocolate with peanut butter.
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What I would like to know is if this device can produces net energy over its lifetime after the total energy to produce and maintain it is taken into account. If there is a net loss then it is in effect just a battery for storing energy with less then 100% efficiency.
Back in high school I used to do this with a beaker of H2O, a bit of acid to improve conductivity, a battery, and a couple of wires. Nice to know that in the succeeding 40 years or so they've improved the process so greatly by replacing the battery with a solar cell.
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This answers it once and for all, robots will be vegetarians!
"Ahh! I see you're in that indeterminate Schrodinger state where - oh, uh
This story is running over and over for quite some time. Each instance it is publicized as a new story. I have seen in in the past year at least two other times.
In what way is this different that replacing the D-cell on my 4th grade science project with a solar cell?
PS.
Fun science project that one was
Ze Atomic Device! It iz Ztolen!
Put it in sunlight and it gives off hydrogen and oxygen, in stoichiometric ratio, from the two sides.
So, if you take this thing and put it in a two-gallon zip bag with a cup of water, in a short time, you have a bomb.
Hydrogen-Oxygen explosions are no joke. This invention sounds like a way for someone to get hurt, by accident. Presumably one would like to have the fuel and oxidizer come off in disjoint, non-connected spaces.
Disclaimer: Note that any descriptions of hypothetical events are metaphorical in nature, and do not intend to portend, suggest, incite, or reflect any overt act, present or future, whatsoever.
Don't take life too seriously; it isn't permanent.
Water vapor is the number 1 green house gas, far exceeding CO2. So, as we move to these "clean" energy sources we are in fact moving toward a much greater green house effect. What are the alternatives? You can use Boron which has a much higher energy density, is safe to transport, and when burnt forms a powder that you can take with you. The result is that when you burn your fuel, your vehicle's fuel tank will end up being heavier!
...And it runs on WATER, man!
Not to be a technology pessimist but how is this better than natural photosynthesis? Can we realistically hope to achieve better efficiency in storing energy in carbon based structures than with the technique that nature provides us? Well, maybe in a reeealy long perspective. We will probably have synthesised life a couple of times in different forms before then.
Sounds like a plain old Solar Cell, rather than deliver it's power via wire to a water electrolysis unit, the electrolysis occurs at the location of the cell??
So.....
The solar cel now needs to be in water and then you have to capture the hydrogen, while trying not to cover up or submerge the cel?
Silly.
(If at first you don't succeed, do it different next time!)
TFA says that the efficiency is under 5% for the 'wired' version and something like 2.5% for the 'unwired'. That's 10x less efficient than electricity-producing solar cells that manage about 25%. But if these have to be submerged in water, we might assume that a good amount of sunlight would be reflected away before it reaches the cell - so maybe the numbers are even worse.
But if you actually need the hydrogen, then you'd have to compare it to a 25%-efficient solar cell plus a 50%-efficient electrolysis unit. So this system is at least 5x less efficient than just sticking some solar panels up and using the electricity to split the water molecules.
The question then is price.
There are plenty of things in the world that contains materials that can kill you if ingested in any significant amount.
Thermometers, various lightbulbs, etc.
The question is: how easily is somebody exposed to said materials for ingestion, and will you be easily exposed to it by other methods (inhalation, touch, etc).
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Hydrogen is difficult to store and leaks out of everything. If we can make methane, propane, ethanol, or some other hydrocarbon fuel directly from sunlight that would be better and compatible with the existing infrastructure. There is some work in this area but it is still very difficult and expensive.
wherein [insert solar collector here (e.g. algae)] is used to output [lipids, hydrocarbons, hydrogen, or electricity], but has a net negative energy return and won't scale worth a crap even if it was energy positive.
Can we algorithmically ban these stories? Hey, just askin.
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If only small amounts are stored, they could be used directly to drive internal combustion engines and generate electricity etc. This could save complexity and cost. You could pass the gasses through a fine metal sieve to protect against flashbacks.
Here's what Wikipedia says about the efficiency of conventional electrolysis:
The energy efficiency of water electrolysis is a measure of what fraction of electrical energy used is actually contained within the hydrogen. Some of the electrical energy is converted to heat, an almost useless byproduct. Some reports quote efficiencies between 50% and 70%.
How can you possibly get "20 times" more efficient than that?
That that is is that that that that is not is not.
...let the off-gas float up a large hill through tubes, burn/redox the hydrogen for power generation, cool the exhaust, store the water at the top of the hill, let it return to the bottom of the hill at night to smooth out energy production...
The gravitational energy from pumping the water up the hill is several orders of magnitude less than the energy of separating the water into hydrogen and oxygen.
If you really want to use sunlight to pump hydro, just evaporate the water at the bottom of the hill and condense it at the top.
Same applies to the proposal by the comment author for using it to purify water. Sure, if you are already cracking the water and burning the stored gasses already you can also use the purified "exhaust" water for drinking supplies. But if all you want is to purify water, solar-powered distillation works quite well enough and you'll get a LOT more purified water.
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How can you possibly get "20 times" more efficient than that?
By not believing wikipedia? LOL Also note wikipedia says "some reports", not that conventional electrolysis (whatever that is) is 70% efficient. Finally, perhaps by 20 times more inefficient, they mean that they waste 1/20 of the energy, meaning it goes from 30% loss to 1.5% loss. Use your imagination, fool! :-)
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My memory of highschool physics tells me that if one side is taking hydrogen out of water, then oxygen must be left... why doesn't that oxygen bubble up as well like the hydrogen does? Or does the split off Oxygen somehow make it to the other side?
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I read it that it could produce at 1000% efficiency. ;)
Just bought a new quantum computer, but I'm uncertain how it works.
What are you burning, think about that for a second. There is a measure of loss in this equation. The hydrogen burned is not destroyed, but it doesn't come back as water. The only thing that is coming back as water is any excess H2O left by the process that wasn't burned.
So, even though the parent post was joking about us running out of water, he's actually right. It's just a matter of many eons in the future instead of a few hundred years with fossil fuels. There are three disasters with using up our water; people living inland are going to burn up potable water which is already scarce (Lake Michigan for example is vanishing as we speak, this is because geothermal pressure is pushing the land upwards and thereby cutting off inlet streams that keep the lake from shedding large volumes), the second is that we will eventually create a desolate water-less earth given enough time, and the third is that as you burn this water in your car for example you have to eject the vapor somewhere which means straight out the back. There are a few problems with that last one, for one, imagine what will happen in the winter it isn't pretty. The other problem? Moisture levels will rise unnaturally which combined with the rising heats of summers will create miserable humid conditions we haven't even witnessed yet as a species.
I say all this, having been a very strong fan of the concept of extracting hydrogen from water. It really would be a boon to us technologically and it would meet or exceed our energy requirements for thousands of years. The problem is, give humanity surplus and we've shown we can greedily consume hundreds of times more than we need per person. Heck, we consume more than we can sustain when there is scarcity. I guess my point is, we wouldn't be using it responsibly, which would bring about the end even faster. For example, referring to Lake Michigan, I could see it vanishes within the lifetimes of many people alive today if we were turning it into energy as greedily as we could. Industrial and chemical manufacturing companies would probably be the largest culprits, especially since they could get energy credits for showing how environmentally friendly they are by burning water and not oil. They'd burn it faster than even homes could, and they'd set their plant right on the lake to do it. It'd go pretty fast, it'd be kind of shocking to most people to see a lake dry up. It's going to dry up eventually, though, even without our help. We should probably see what we can do about fixing that, that'd be a better project than this one.
That's my two cents.
Yes, Nocera holds lectures telling everyone about this super invention, which is simply a material to do electolysis with, which is not more or less efficient than other materials, but it mimics nature. to get the watersplitting going he uses a silicon solar cell, like any one we normally see on rooftops, and of course if that cell creates a potential you get bubbles. I can do that in my appartment anny day. This is how small knowledges can captivate many minds with crap..It only leads to distractions and delays..
Cobalt catalysts are also an attempt to do something tha