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Power Technology

MIT's 'Artificial Leaf' Makes Fuel From Sunlight 158

Posted by Soulskill from the do-you-think-energy-just-falls-off-trees dept.
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."
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MIT's 'Artificial Leaf' Makes Fuel From Sunlight More

MIT's 'Artificial Leaf' Makes Fuel From Sunlight

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  • This was already posted on slashdot
    • ya it's a dupe I'm pretty sure we saw this at least a few weeks if not a couple months ago.
    • 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 [slashdot.org]
      Not exactly a dup; they link to different articles.
      This one's article [mit.edu] has a video showing the prototype in operation, which is kind of cool.
      The old one's article [sciencemag.org] has no video, but they basically make the same points in text.
    • 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.

      • Re:Duplicate (from the 19th century) (Score:4, Funny)

        by GrumpySteen ( 1250194 ) on Friday September 30, 2011 @12:51PM (#37569794)

        > Seems to me like saying a Reese's Peanut Butter Cup is a new discovery because they mixed chocolate with peanut butter.

        That's fucking incredible!! When did they do that?!?! Why wasn't I told????

      • Re: (Score:2, Interesting)

        by Anonymous Coward

        This is, in fact, a revolutionary new catalyst potentially worth billions. It does the same thing as conventional electrolysis, but is more than 20 times as efficient as just sticking two wires into a bucket. When I saw Nocera present this research at the Spring ACS conference, my jaw was just about on the floor.

        • 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?

          • 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! :-)

      • Seems to me like saying a Reese's Peanut Butter Cup is a new discovery because they mixed chocolate with peanut butter.

        Please, I think we all know that they mixed peanut butter with chocolate.

        • Seems to me like saying a Reese's Peanut Butter Cup is a new discovery because they mixed chocolate with peanut butter.

          Please, I think we all know that they mixed peanut butter with chocolate.

          I'm thoroughly convinced they just mixed sugar with both.

    • No, one of Nocera's previous papers was posted [slashdot.org], not the one published yesterday. This one is a lot more in-depth synthetically and has much stronger characterization and shows that it actually works as a full system - the earlier paper was just a communication saying, "Look, we did this first!"

  • Any minute now... (Score:3)

    by ackthpt ( 218170 ) on Friday September 30, 2011 @12:09PM (#37569196) Homepage Journal

    OPEC assassins will strike and this will be nothing more than a small pile of mysterious rubble and ash in Cambridge, Massachusetts.

    • The world of Syndicate doesn't happen until 2069, so calm down.

    • Re: (Score:2)

      by mevets ( 322601 )

      I think you mean Texans....

      • No most people in Texas don't have anything to do with oil. Some of us do work for the oil companies but we don't have any love of them.

      • I think you mean Texans....

        Yes because texans have no interest in hydrogen production and distribution ... oh wait ... http://www.texash2coalition.com/ [texash2coalition.com]

        • Re: (Score:2)

          by mevets ( 322601 )

          No offense to Texans; really meant Texan politicians.

          • No offense to Texans; really meant Texan politicians.

            FWIW the state government is involved. I'd wager there are quite a few texas politicians that are all for developing new in-state energy sources, state infrastructure, products to export to other states, etc.

            • Re: (Score:2)

              by mevets ( 322601 )

              and also FWIW there have been quite a few texas politicians that have chosen extremely violent attacks to maintain their position in the petroleum market. Sorry they come from your neck of the woods; shouldn't reflect badly on you. Maybe next time you see some psychopath with rising popularity coming out of the oil families you could do us all a favour by treating him to a 'texas suicide'. It worked well for the Enron whistleblower; I think it could be more widely applied.

              • Not my neck of the woods, I'm in California. I'm not defending Texas, I'm just correcting uninformed politically biased statements. Apologies if you find this offensive.

    • Re: (Score:2, Flamebait)

      by Archangel Michael ( 180766 )

      No Worries for the Greens, The government will give a couple billion dollars to prop up yet another failing "solar" company that cannot make it without a handout.

      People who act like the (R) are better than the (D) and visa versa are just fooling themselves and or worse, useful idiots.

      • Re: (Score:3, Insightful)

        by fnj ( 64210 )

        Yes; the (R) and (D) for the most part is just a big conspiracy to block any meaningful change. Of course you only mentioned one "side" which is no better than the other. In truth both "sides" are evil.

        The real battle is between the establishment and the outsiders - people who actually have independent critical thought.

        • Of course you only mentioned one "side" which is no better than the other.

          Someone does not understand the meaning of "vice versa" (even if he did spell it wrong).

          • Re: (Score:2)

            by fnj ( 64210 )

            Adversus solem ne loquitor.
            Kleine Siege gefeiert werden sollte.
            Good point. I new that abortion of a clause was in there for a reason.

        • Re: (Score:3)

          by ewieling ( 90662 )
          It seems to me (R) generally want to deregulate business and regulate our personal lives. The (D) generally want to regulate business and deregulate our personal lives. This is the real difference.

          • It seems to me (R) generally want to deregulate business and regulate our personal lives. The (D) generally want to regulate business and deregulate our personal lives. This is the real difference.

            Those are just the talking points. The (D)s want to regulate your personal life, they just use environmentalism, egalitarianism, and "compassion" as their excuses, rather than religion and traditional morality. The (R)s want to regulate business to pick the winners.

          • Re: (Score:3)

            by lgw ( 121541 )

            The (D) want to regulate my video games, my shower, my toilet, my trash, my building materials, my car, my power sources, my energy consumption, my ...

            The (R) only seem to want to regulate my sex life.

      • No Worries for the Greens, The government will give a couple billion dollars to prop up yet another failing "solar" company that cannot make it without a handout.

        As opposed to the trillions of dollars in 'handouts' to Saudi Arabia and the rest of the Middle East to keep the oil flowing? Or did you think we like to support backwards misogynist despots because they're just like us? (A reasonable supposition, I suppose).

        • Or did you think we like to support backwards misogynist despots because they're just like us?

          I think it's because their hands are so soft [slate.com]

        • Re: (Score:2)

          by lgw ( 121541 )

          You're just making up numbers, which doesn't help your point any. Anyhow, don't we only get some trivial % of oil from the Middle East, with most of it coming from much closer (hello, Canada)?

          • Anyhow, don't we only get some trivial % of oil from the Middle East, with most of it coming from much closer (hello, Canada)?

            That's like saying you don't buy electricity from the power company because of the fact that the electrons that arrive at your house aren't the same ones that left the power station.

            Oil is a fungible commodity. If they stopped producing it in the Middle East, then the countries closer to them would start buying up the Canadian and South American oil we now consume, driving up the price we pay by hundreds of dollars per barrel. That's why we prop up Middle East producers.

            • Re: (Score:2)

              by lgw ( 121541 )

              Sure, sure, but is there any reason we should care who controls those countries? Whoever is in charge, they're going to sell that oil (or we'll see the first non-greedy government in history which would be something!), and it's not likr we're getting a special deal or anything. I don't get the rational here.

      • The government props up the oil industry, too. And judging from their profits, they most decidedly could make it without the handout.

        So it's not clear to me that money diverted to green energy is any worse spent than money diverted to black gold.

        • But Oil Companies pay a shit load of taxes, and the government gets its share on every gallon of gas sold. The real sad thing is that the government makes more on every gallon of gas than do the oil companies. A shit load worth. Green Companies like GE don't pay any taxes or get BILLIONS in loan guarantees only to go belly up four months later.

          I'm not a big Corporation fan, in fact, I would establish a bunch of rules for corporations that would prevent them from affecting politics at all (no PAC, No Lobby,

    • Re: (Score:3)

      by elrous0 ( 869638 ) *

      No, they'll just wait and see if it's even practical to manufacture large scale. If it is, they'll either swoop in and buy up all the companies/patents involved or have their government lapdogs in Congress bury it under volumes of obstructive laws and regulations (you see they DO believe in govt regulation, just as long as it effects competitors but not themselves).

      • Exactly. It will be seen as a "National Security" measure to bury it...

      • Re: (Score:2)

        by tsotha ( 720379 )

        you see they DO believe in govt regulation, just as long as it effects competitors but not themselves

        Of course big companies believe in government regulation. The more the better, since the overhead of lawyers and government regulation specialists is trivial to the Exxon's of the world but enough to put small competitors out of business. It's even better when they can throw a bunch of money around in Washington and capture regulatory agencies.

    • Comment removed based on user account deletion

    • Re: (Score:2)

      by sjames ( 1099 )

      Actually a hit squad from Monsanto's legal department will claim that unless it dies when you spray it with roundup, they own it now.

  • Perhaps some of these New Submitter's need to do some look-ups before trying to post new information, AKA News.

  • Losing Hydrogen (Score:5, Funny)

    by jameskojiro ( 705701 ) on Friday September 30, 2011 @12:14PM (#37569274) Journal

    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.

    • I wonder how much of a risk this REALLY is. Would human use of H2 and the resulting loss to space from leaks even outweigh the influx of H2 from accretion? Of what leaks, what makes it into space?

      And don't worry, so long as you take care of your stillsuit, it will take care of you.

      --PM

      • Re: (Score:2)

        by fnj ( 64210 )

        I assume you're joking. Do you have any idea of the amount of energy locked up in surface water in the form of hydrogen-water bonds? Compared to annual energy usage by humans, times, say, one million?

        • Not joking. This is obviously not a short-term problem, I'm wondering just how long-term of a problem it really is, and if any possible human-caused additional leakage could ever be significant compared to the natural loss rate.

          I.e., does it take only a million years for the effects to be noticeable, or does it take 10 billion? If it's less than the expected habitable lifetime of the planet, then it's an interesting question.

          --PM

      • Re:Losing Hydrogen (Score:4, Informative)

        by wagnerrp ( 1305589 ) on Friday September 30, 2011 @01:12PM (#37570120)
        Hydrogen is reactive. It will react with something on the way up through the atmosphere, that makes it sufficiently heavy to stick around. The problem with helium is that it is inert. It's perfectly content on its own, so it will simply float to the top of the atmosphere and exist in trace densities not economical to capture.
        • This is true, unfortunately there is another highly reactive oxidizer [wikipedia.org] very high up in the atmosphere that any escaping hydrogen will react with so I wouldn't be too worried about it leaving the planet entirely, but we might have other problems.
    • When you burn the hydrogen it becomes water again.

    • Don't worry, we will put our cities under gigantic glass domes.

    • Well this tech could be used in a stationary power plant. Just pure dihydrogen monoxide comes back out, it's just a very complicated form of solar power.

      Which means it will probably be less efficient than PV or solar-thermal :-(

      If it's a lot cheaper it could still be useful.

    • 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.

      With rising oceans this might turn out to be a good thing...

  • Oh boy (Score:3, Funny)

    by JustAnotherIdiot ( 1980292 ) on Friday September 30, 2011 @12:15PM (#37569282)
    The energy crisis is solved for the 6th or 7th time this year.

    • Re: (Score:2)

      by jovius ( 974690 )

      It seems that there's a whole lot of great development and innovation happening in the field.

      • Re: (Score:2)

        by lgw ( 121541 )

        The solution to high commodity prices is high commodity prices - amazing how that works.

  • Now they just need to do that with CO2. Release the O2 [yale.edu] and sequester the carbon to make graphite, graphene, and/or diamond [wired.com].
    • Or just make food, like plants

    • Now they just need to do that with CO2. Release the O2 [yale.edu] and sequester the carbon to make graphite, graphene, and/or diamond [wired.com].

      The artificial leaf epithet would seem to be a better fit for binding up carbon and producing O2.

    • Re:Now do it for CO2 (Score:4, Informative)

      by Attila Dimedici ( 1036002 ) on Friday September 30, 2011 @12:39PM (#37569626)
      Actually, you bring up a decent point. Hydrogen is not very energy dense. This system would be great if we had a practical fusion reactor, but we don't. A much superior system would be one which takes sunlight, CO2 and water and produces a complex hydrocarbon that could then be used as fuel.

      • It's called "plants".

      • Re: (Score:3)

        by h4rr4r ( 612664 )

        Once you have hydrogen and a source of CO/CO2 like a coal power plant you can make whatever hydrocarbons you want.

        • I was thinking along the lines of something that gets the energy to do this from sunlight. Actually, there are things which do so and are being used to create biofuel. It would just be nice if we could stick something like these "leaves" in a water and CO2 bath in the sun and get complex hydrocarbons. On the other hand, the methods they have for doing that already are actually pretty good.

  • Clean water? (Score:3, Interesting)

    by Anonymous Coward on Friday September 30, 2011 @12:25PM (#37569422)

    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.

  • 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.)

    • 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.)

      Physical efficiency may not be a big deal here. If you are using inexpensive materials and can get the device built reasonably cheaply and it has long term stability (several largish engineering 'ifs' here) then overall energy conversion rates aren't too critical. There is lots of sunlight and lots of water so you can trade off efficiency for square footage (to some degree, it can't be terribly bad at conversion).

      The devil will be in the details and as TFA states, there is a lot of engineering work to be

    • 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.)

      Hey, it's not like this process is in competition with some more efficient process for that sunbeam. This device would be capturing otherwise unharvested sunlight, so it's closest competition is producing Zero energy in comparison.

      • Re: (Score:2)

        by lgw ( 121541 )

        The device has a fixed cost to produce, and thus needs to produce power valued in excess of that fixed cost in its lifetime or it's a net loss. That's unlikely with 2.5% efficiency.

  • Perfect solution for lumpy power sources. (Score:1)

    by Anonymous Coward

    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.

  • 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.

    • Re: (Score:3)

      by Bengie ( 1121981 )

      The real question is if it is more efficient than just charging a better with a solar panel. Since that Hydrogen is just a storage medium for "energy".

    • Re:Back in High School (Score:5, Informative)

      by Dr_Barnowl ( 709838 ) on Friday September 30, 2011 @01:09PM (#37570082)

      The innovative bit is the cobalt catalyst. A lot of other designs use toxic electrolytes (as you mention) or expensive rare metal catalysts. This one has the advantage that all the raw materials are relatively cheap, for a solar panel design - no expensive platinum, gadolinium, etc.

  • 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

    • Re: (Score:3)

      by nomel ( 244635 )

      Having a non corroding electrode, not requiring lots of electrolytes, and doing it all with cheap materials, is what makes it very interesting.

      This is an interesting electrolysis problem more than a "power something with a solar cell" problem.

  • 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

    • "Hydrogen-Oxygen explosions are no joke." - Yes they are!

      Few fuels contain as little energy per unit volume as hydrogen at atmospheric pressure. Two gallons of H2 is less than the fuel in a cigarette lighter.

      My high school chemistry teacher used to fill balloons with H2 and O2 at stoichiometric ratio and hold them over a bunsen burner (on a 1 meter stick). They make a large pop of course, but the effect is not much larger than when the balloon is filled with pure O2 and the only fuel is the balloon itself.

  • 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.

  • 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?

    • Did your high school physics include the concept of an anode and a cathode, with the negative/positive ions bubbling up from each, and the necessity of the divider referred to in the summary?

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