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Power Earth Science

Mimicking Photosynthesis To Split Water 257

plantsdoitsocanwe writes "An international team of researchers led by Monash University has used chemicals found in plants to replicate a key process in photosynthesis, paving the way to a new approach that uses sunlight to split water into hydrogen and oxygen. The breakthrough could revolutionize the renewable energy industry by making hydrogen — touted as the clean, green fuel of the future — cheaper and easier to produce on a commercial scale." This was a laboratory demonstration only and the researchers say they need to bring up the efficiency.
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Mimicking Photosynthesis To Split Water

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  • by pchan- ( 118053 ) on Sunday August 17, 2008 @09:27PM (#24640021) Journal

    This was a laboratory demonstration only and the researchers say they need to bring up the efficiency.

    Shame on you, submitter. This is Slashdot, you're supposed to write a sensational story and let the comments tell us why it actually won't work. If you're going to write things that make sense and treat us like adults, you're missing the entire point.

  • by StefanJ ( 88986 ) on Sunday August 17, 2008 @09:28PM (#24640037) Homepage Journal

    We are in a phase similar to the Cambrian Explosion, when all sorts of lifeforms with weird body plans gave it a shot . . . but which were winnowed down to a few by the time things started to crawl on land. Chances are just a few of the many alternative energy techniques being fooled about with will pan out commercially . . . but this is a necessary process.

    Now, cue the cranky "Gee, Slashdot posts stories about dramatic advances in solar energy all the time; why doesn't my car run on solar cells yet?" posts.

    • by BlueParrot ( 965239 ) on Sunday August 17, 2008 @09:41PM (#24640121)

      It is easy to get a breakthrough in one criteria if you shaft the other ones.

      As an example, you could very well produce hydrogen very efficiently from sunlight without any fancy tech by simply focusing enough sunlight to raise the temperature to 2500 C, at which point water spontaneously separates into hydrogen and oxygen through thermolysis. This would be possible completely without moving parts, no toxic materials, and no new technology.

      Problem? It would be much more expensive than making hydrogen from natural gas.

      This is why these vapourware stories are so useless. There will be a vast number of ways to convert solar energy into hydrogen or electricity, I could start listing various ways to do it in all kinds of elabourate manners, but it does not mean any of them are good, nor does it mean any one of them is likely to be more efficient than simply using a conventional steam turbine and solar concentrators.

      Seriously, what you are attempting to beat is something which, depending on temperature achieved, can have up to 40% conversion efficiency, economies of scale, and uses well tested technology. When you can beat solar thermal then you can start trying to have a go at nuclear or coal, which have a number of other advantages. Simply finding yet another way to convert solar energy into useful work is quite a different thing from solving our energy problems.

      • by MikeUW ( 999162 ) on Sunday August 17, 2008 @10:13PM (#24640365)

        This sounds like a bit of a red herring to me.

        Are you saying that we should abandon any new idea or technology if, in its infancy, it isn't better than what we already have? I think that would put an end to a great deal of innovation that we could benefit from in the future.

        • How about we let them work out the bugs before posting to slashdot?

          Seems a lot of the stories get posted to get into "the media" without having the required science/adverse analysis/hostile counterpoint process done.

        • by BlueParrot ( 965239 ) on Sunday August 17, 2008 @11:35PM (#24640867)

          No, I'm merely saying that the fact that you can invent many different ways of doing soemthing is in no way an indication that fundamental problems with it will suddenly vanish. It is not rational to expect solar to suddenly become a silver bullet merely because there is a lot of proposed ways to make solar cells.

          Perhaps an analogy is in order. There are LOADS of ways to convert nuclear energy into electricity. There's turbines, direct electrostatic conversion, magnetohydrodynamics, thermoelectric solid state devices, sterling engines, brayton cycles, thermochemical hydrogen production, high temperature electrolysis, etc etc...

          Now despite of this you don't see people randomly assuming the price of nuclear is going to drop by a factor of ten within "a few years", because people know that with nuclear, as with solar, and as with coal, the most efficient ( in watts/dollar terms ) generation scheme is to heat one side of a turbine and cool the other one. The other techniques, while interesting from a scientific perspective, are simply inferior in one way or another. They may be inefficient, fragile, may not scale, may involve expensive materials / maintainence etc...

          What gets on my nerves with the way these solar technologies are described as major breakthroughs is that they ALWAYS, without exception, are described as something which will revolutionise the energy situation, without as much as a shed of proof that they will even be economical, durable, efficient... They are always along the lines of "Here is yet another way to use solar energy, IF it turns out to be cheap ( which we have no evidence suggesting it will be ) THEN it will change the world.".

          That's not a breakthrough, it's speculation of greener grass with no evidence to back it up.

          • by TapeCutter ( 624760 ) * on Monday August 18, 2008 @02:47AM (#24641889) Journal
            They are not claiming a breakthrough in energy production, they claim to have made a breakthrough in artificial photosynthisis, no small feat IMHO. Also the CSIRO are not in the habit of making unsubstantiated claims and their evidence has been published in a peer-reviewed journal.

            It's pretty obvious you are looking for a different breakthrough and it's a certainty you won't find it if you are unwilling to entertain NEW knowledge that MAY be relevant.
            • So far as I understand TFA, the claims of artificial photosynthesis aren't well founded - what they have actually done is to use manganese as a catalyst to improve the efficiency of electrolytic hydrogen generation.

              That's good, but the fact that they used manganese doesn't mean it's photosynthesis just because chlorophyll also happens to have manganese in it.

              It's just a fancy catalyst in this implementation.

              • Re: (Score:3, Insightful)

                by TapeCutter ( 624760 ) *
                "It's just a fancy catalyst in this implementation."

                Hmmm, they invented a novel polymer membrane that mimics "a key process in psynth", wasn't it a novel kind of membrane that made fuel cells possible? IANA Industrial Chemist, their contact details are all over the article.

                "That's good"

                That's the point! It helps 'self-educated' geeks tell the difference between science, psudeo-science, and hype outside their sphere of expertise (or lack therof), OTOH there maybe no hope for those like the troll who
                • by Rei ( 128717 ) on Monday August 18, 2008 @12:19PM (#24646731) Homepage

                  No, they're starting with the exact same (expensive) membrane used in fuel cells -- nafion [wikipedia.org]. They've just taken this membrane and added a manganese-based catalyst to it.

                  I'm amazed that most people never point out the huge, glaring flaw in this notion of setting up big solar electrolysis plants in the sunny desert southwest. Let's ignore the problems of how corrosive the released hydrogen is to your system, which usually makes solar electrolysis have short lifespans. Let's do the same with the free oxygen. And the water. And let's ignore algae growth, which is a problem in most systems that mess with water. And let's ignore hydrogen embrittlement when it comes to raising storage and transportation costs. And let's ignore how huge hydrogen storage tanks have to be due to its very low density, a fact that makes the prior issue even worse. And let's ignore that it has a ridiculously low ignition energy, burns in almost any fuel-air mix, readily evolves deflagrations to detonations, pools under overhangs, enters pipes and follows them to their destinations, burns clear and vigorously, and so on. And let's ignore that leaked hydrogen destroys ozone. And let's ignore that fuel cell stacks are quite inefficient, and that a fuel cell stack strong enough to power a car will cost you hundreds of thousands of dollars. We're talking about *consuming lots of water in a desert* -- enough to power vehicles around the world. What the heck kind of plan is that?

                  Electricity is our common energy storage and usage medium. Why are we talking about "very low" efficiency, in-the-lab, probably horrible lifespan and very costly hydrogen-solar cells when we could put photovoltaic cells or solar thermal on the same land, get much better effiency from a much cheaper system, transmit the electricity efficiently (92.8% average in the US), rectify it efficiently (~93% charger efficiency), charge/discharge it efficiencly (96%-99.9% in li-ion), and convert that to kinetic energy efficiently (85-90% typical electric motor efficiency in a normal drivecycle), in a vehicle that uses batteries that cost *literally* an order of magnitude less than said fuel cells, can level-3 charge in as little as 5-15 minutes (depending on the type), and have longer lifespans to boot?

                  The "hydrogen economy" is just a silly concept; nothing about it makes sense in comparison to an EV economy with modern automotive li-ion batteries.

          • by Jeppe Salvesen ( 101622 ) on Monday August 18, 2008 @03:53AM (#24642187)

            Good luck raising cash for investment while being extremely sober in your analysis!

      • Re: (Score:2, Funny)

        by ksd1337 ( 1029386 )

        As an example, you could very well produce hydrogen very efficiently from sunlight without any fancy tech by simply focusing enough sunlight to raise the temperature to 2500 C, at which point water spontaneously separates into hydrogen and oxygen through thermolysis.

        This is why these vapourware stories are so useless.

        According to your first point, these stories would be called gasware stories instead of vaporware stories.

      • Re: (Score:2, Insightful)

        Correct me if I'm wrong, but isn't the idea to be able to store solar energy this way? Even with solar-driven steam turbines, you can't generate any power at night and afaik, there's no effective way of storing energy. Making hydrogen to run fuel cells at night or when extra power is needed wouldn't really compete with any power source, only supplement them.
        • Re: (Score:3, Informative)

          by rcw-home ( 122017 )

          Even with solar-driven steam turbines, you can't generate any power at night and afaik, there's no effective way of storing energy.

          Yes [sandia.gov], there [treehugger.com] is [pesn.com].

          Not saying this discovery wouldn't be useful, though.

      • Re: (Score:2, Interesting)

        I think focusing sunlight to thermolyse water in that way might violate thermodynamics. I think you'd need to get closer to the sun. Maybe someone can give us hard numbers...
        • by BlueParrot ( 965239 ) on Sunday August 17, 2008 @11:40PM (#24640903)

          I think focusing sunlight to thermolyse water in that way might violate thermodynamics. I think you'd need to get closer to the sun. Maybe someone can give us hard numbers...

          The sun's surface temperature is more than 5000 C , so the laws of thermodynamics certainly don't prevent you from reaching 2500 C using the light emitted from it.

      • by ceoyoyo ( 59147 )

        The difference is that the technique you're describing, while it would work, would be very difficult to improve the efficiency of. The technique described in the article has a pre-existing example of a high efficiency implementation.

      • The problem is that you're actually talking about two different things. One is a power plant, one is a fuel source.

        I submit that if you could use this process to economically produce hydrogen and oxygen, you could create power plants that use these as fuel, and possibly create electrical energy better than nuclear or coal. Better due to greatly reduced environmental impact.

        And fuel cell cars are known to be feasible right now, the main problem with them is finding an economical, non-fossil fuel source for

        • Re: (Score:3, Informative)

          by Ihlosi ( 895663 )

          Another use for this technology would be a sort of energy pack that goes on the roof. A water line goes in, hydrogen comes out and is stored in a fuel cell which powers the house.

          Fuel cells don't store hydrogen - they use it as fuel. Hydrogen storage is a can of worms entirely separate from the fuel cell that has its own challenges.

          Problem is what to do with all the waste oxygen.

          Um, what problem ? You either store it, too, and use it when your fuel cell generates electricity, or you just release it into t

      • Re: (Score:3, Insightful)

        by Bombula ( 670389 )

        No offense, but the MIT is un doubtedly fmailiar with all of the points you raise. The reason why this technological development is interesting is not because it is revolutionary, but because it is cheap as well as efficient.

        If your read the article, you'll see that whole point is that they've found a way to electrolyze water at room temperature with inexpensive materials. Previously, electrolysis required high temperatures and/or expensive catalysts like platinum for the annodes. Well, that's a pretty

    • Re: (Score:3, Interesting)

      I agree with you. How about these guys?

      http://web.mit.edu/chemistry/dgn/www/research/e_conversion.html [mit.edu]

      They bounced into the news a few weeks ago.

    • Yessss, Oil is black and sweet. (Aaaahh the Sun! We hates it, my precious! We hates it!)

      On a slightly less silly note, I like this development. And wierd body plans suit the laboratory environment quite well.

      I imagine we could move away from the great black poison in the dirt eventually, if our good wierdly-planned bodies in the laboratory keep up the good work.

    • by QuantumRiff ( 120817 ) on Sunday August 17, 2008 @10:05PM (#24640305)

      Actually, your answer to why your car doesn't run on solar yet is rather simple. Because we haven't needed solar power to win a war yet. Nuclear got everything it needed to get off the ground, working, demonstrated, and dropped. It was needed to fight a war. Radio, space ships, etc? Same things. The US Military is just starting to come to the conclusion that half their vehicles exist solely to deliver fuel and supplies to the other half(the fighting half) and that there is a huge risk in running tankers full of Diesel and gas to forward areas, as they become very easy targets. Destroy the supply lines, and those 70Ton M1A tanks become very large, immobile targets. Add to that, the skyrocketing cost of fuel the military has to buy. (not to mention, the huge costs of keeping 50% of your peopled tied up in support roles).

      THat is why the military is starting to look at things like solar, small nuclear plants, etc. They are looking at hybrid vehicles that work like a train, the whole powertrain is electric, powered by a generator. Some of these vehicles are pretty cool, they could sit there and idle at the forward CP, and you just plug all your radios and equipment into the truck. No need to lug a generator with you.

      I have a feeling things are going to improve quite quickly over the next few years. Nothing improves technology like fat government contracts!

      • by budgenator ( 254554 ) on Sunday August 17, 2008 @10:23PM (#24640433) Journal

        Gas as in gasoline is rarer the hen's teeth in the US Army, the only place I remember it being used is in the mess for running stoves, ovens, and water heaters; and I retired back in 1985. I wouldn't be surprised if there weren't new stoves that ran on JP4, military jet fuel and or water-clear kerosene by now. Gasoline is just nasty dangerously flamable stuff especially around bombs and bullets.

        • by dbIII ( 701233 ) on Sunday August 17, 2008 @11:45PM (#24640951)

          I wouldn't be surprised if there weren't new stoves that ran on JP4, military jet fuel and or water-clear kerosene by now

          In the late 1980s a mountaineering stove came out that could run on those fuels - the whisperlight international. Admittedly one of the first of them was hurled into a crevasse on Mt Erebus in Antarctica by a critic. However the later ones were better and there have been lot of other multi-fuel stoves since then.

        • by n3tcat ( 664243 ) on Monday August 18, 2008 @01:22AM (#24641467)

          We still use JP for our mil vehicles, but we use a lot of NTVs (non tactical vehicles) now which are from I have seen over the last few years a fairly even mixture of gas and diesel.

          The stoves, heaters, and yes, we have a/c now in even the training tents, all run off electricity which comes from generators that are fueled by something brought in by contracted companies. Diesel? Gas? I don't know because I haven't seen the paperwork for the contracts. It all depends on who we contract out for the generators and what kind of generators they bring in for us.

          I think that was the biggest change in Army ideology over the last 20 years or so... they've shifted a huge portion of the green suiters' work onto civvie companies and contractors.

    • by Ihmhi ( 1206036 )

      More importantly, why doesn't my solar cell have wheels on it yet?

    • by Opportunist ( 166417 ) on Sunday August 17, 2008 @11:43PM (#24640935)

      You know what a joke during the early times of the Newcomen steam engine was? You need three mines to run a steam engine. One mine where you apply it, one coal mine to fire it and one silver mine to pay for it.

      Know what? It changed.

      If people would've taken the position you have now and ignore Newcomen's development, the industrial revolution would not have happened, at least not in the way we know it. Yes, the steam engine was horribly inefficient and in most cases uneconomical until Watt made his improvements. After that, though... well, you know history I'm sure.

      What we have here is not even yet the equivalent of a Newcomen machine. This has a long, long way to go, give it a decade and good funding and this can go a long way.

    • That is very much how the motor car industry started out - you had well over 3000 startup companies all across North America and Europe, experimenting with the combustion engine, and inventing different improvements (carburettor, cooling fan, 2-stroke, 4-stroke and 8-stroke engines). Eventually, over time they merged together to form larger companies and eventually forming a handful of corporations.

      How many solar panels would they need on a car to have a completedly closed system (solar panels to generate

      • Re: (Score:3, Informative)

        by lgw ( 121541 )

        You can't really run a car with solar panels on the car, for a thousand obvious reasons. You can, however, run a car with solar panels covering the parking space you have at home and at work (at most lattitudes, anyway) if you can store that power densly and safely, and transfer it quickly. Plus you'd get covered parking.

        The total area of parking spaces in America, if covered with the best existing technology solar cells, would on average cover all of our elecitrical needs, or the needs of the daily commu

  • Not new (Score:5, Informative)

    by BhaKi ( 1316335 ) on Sunday August 17, 2008 @09:34PM (#24640081)

    This was a laboratory demonstration only and the researchers say they need to bring up the efficiency.

    There have been numerous such laboratory demonstrations on different ways to produce hydrogen easily. But the attempts to bring up efficiency are just what failed.

    • Re: (Score:3, Informative)

      by wrp103 ( 583277 )
      Is this a dup of this story [slashdot.org] from July 31?
      • Re:Not new (Score:5, Informative)

        by quantumred ( 1311571 ) on Sunday August 17, 2008 @10:23PM (#24640431)

        I don't think so, although I initially thought the same thing.

        The MIT process (from July 31 /.):
        "..catalyst is made from cobalt, phosphate and an electrode that produces oxygen from water by using 90 percent less electricity than current methods, which use the costly metal platinum."

        The Monash team (todays /.):
        "..using just sunlight, an electrical potential of 1.2 volts and the very chemical that nature has selected for this purpose". The chemical seems to be "a form of manganese".

    • What I'm wondering is, is it any more efficient than using the 1.2 volt potential to just electrolyze the water?

  • by the eric conspiracy ( 20178 ) on Sunday August 17, 2008 @09:42PM (#24640125)

    Why not just put in a solar panel? 3x the efficiency of the best plants and none of those messy chemicals, plus much better applicability.

    • Re: (Score:3, Informative)

      by sokoban ( 142301 )

      Because normal electrolysis of water isn't very efficient at producing hydrogen.

      This is a system for generating Hydrogen which can then be stored and used as a fuel either in an internal combustion way or with a fuel cell.

      Solar panels are a way to generate electricity which then must be stored and used. Storage of electricity is generally a pretty big inefficiency, and solar panels only really work when the sun is out, so they necessitate storage or supplemental energy generation systems.

      • The normal electrolysis of water efficiencies usually reported includes the losses that go into generation of electricity. If you don't have that step (like with a solar cell that is generating electricity) the efficiency is pretty good (50-80%).

        • Re: (Score:3, Interesting)

          by ceoyoyo ( 59147 )

          I've got sunlight and I want hydrogen. Whoops, the inefficiency in the solar cell is still part of the process.

    • In order to match the best application, with the best method, you often times have to make a trade off. For example, a satellite gets some power from solar cells because it's more efficient than bringing all the fuel it would need with it, or running a really long power cord.

      I imagine that this new method might find applications where there is plenty of both sunlight and water. Perhaps large ocean liners, and offshore drilling rigs.
    • Re: (Score:2, Funny)

      by felipekk ( 1007591 )

      Because you are only truly green if you do it like the plants!

  • by the_povinator ( 936048 ) on Sunday August 17, 2008 @10:17PM (#24640387) Homepage
    TFA says that a voltage of 1.2V is required, along with sunlight. The theoretical voltage required to split water is 1.23V. The energy supplied by the electrodes at 1.2V is obviously way more than you could practically retrieve from the H2 (which maxes out at 1.23V but you have to factor in efficiency). So this device is of no practical value even if scaled up. Online I see that as far back as 1981 (ahref=http://prola.aps.org/abstract/PRL/v46/i17/p1153_1rel=url2html-26843 [slashdot.org]http://prola.aps.org/abstract/PRL/v46/i17/p1153_1>) a method was published that used sunlight and an electrode potential of 0.65V to split water. So I don't understand the fuss about the current paper.
  • by notgm ( 1069012 ) on Sunday August 17, 2008 @10:17PM (#24640391)

    they must be working up to the atom. this means war! bomb the crap out of those planty bastards.

  • by Anonymous Coward

    There are three crucially important characteristics here:

    (1) stored energy,
    (2) direct from sunlight, and
    (3) zero carbon footprint.

    (1) Is important because:
    (a) stored energy can be used as a fuel (in this case, it IS a fuel), and
    (b) stored energy can be used at times when the primary source is not available (an energy buffer).

    (2) is important because:
    (a) only one process is involved. There is no "convert to electricity, then electrolyse water" type of two-step process. Improve one efficiency, and the whole p

  • by Doc Ruby ( 173196 ) on Monday August 18, 2008 @12:34AM (#24641207) Homepage Journal

    Photosynthesis has a maximum theoretical efficiency [fao.org] of about 11% from sunlight into energy stored in biomass (eg. the plant). But in the wild, it's only 3-6% efficient.

    Familiar PV cells already get 15-25% efficiency; experimental concentration cells get over 45%. And the PV outputs electric current, not just biomass to burn inefficiently.

    Those cells cost a lot more energy to make than plants do, but they last over 30 years, while most plants don't.

    I'm not so sure that mimicking photosynthesis is such a great way to go.

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Familiar PV cells already get 15-25% efficiency; experimental concentration cells get over 45%. And the PV outputs electric current, not just biomass to burn inefficiently.

      Those cells cost a lot more energy to make than plants do, but they last over 30 years, while most plants don't.

      I'm not so sure that mimicking photosynthesis is such a great way to go.


      On a mobile vehicle, if you want to use the energy from sunlight utilising PV cells, then you must (a) have the PV cells on the car, and (b) only use t

    • Re: (Score:2, Insightful)

      by Omegium ( 576650 )
      The cost of the device is also important. A low efficiency is not a problem if the device is very cheap. If it is cheap enough to for example cover your whole roof with it, you can live with the lower efficiency.
  • Carbs (Score:3, Interesting)

    by soundguy ( 415780 ) on Monday August 18, 2008 @12:48AM (#24641287) Homepage

    FTFA: This process of "oxidizing" water generates protons and electrons, which can be converted into hydrogen gas instead of carbohydrates as in plants.

    Well, hydrogen is nice and all, but I can see an equally compelling reason to work on generating carbohydrates (preferably edible) with this method instead. Especially in places with no plants where having a food source would be awesome - places like long-range manned space flights, as-yet-un-terraformed planets like Mars, and god-forsaken hell-holes like the middle east and the Sahara.

    "Soylent green is...well, it's sunlight and carbon dioxide...and 1.2 volts"

  • They say they need to bring up the efficiency, but I didn't see where they are at. Are they at .1%, 1%... what's up? I think a plant is 10% while a photovoltaic cell commercially available is around 10-20%. Just wonder how far they have to go.

  • Lisa: Dad, look what I made for the science fair!

    Homer: What good is that? It just keeps spinning and spinning.

    My version of hydrogen fuel- all spin, no substance. (of course Lisa had invented a perpetual motion maching)

"Conversion, fastidious Goddess, loves blood better than brick, and feasts most subtly on the human will." -- Virginia Woolf, "Mrs. Dalloway"