Bionic leaf turns sunlight into liquid fuel

New system surpasses efficiency of photosynthesis


The days of drilling into the ground in the search for fuel may be numbered, because if Daniel Nocera has his way, it’ll just be a matter of looking for sunny skies.

Nocera, the Patterson Rockwood Professor of Energy at Harvard University, and Pamela Silver, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at Harvard Medical School, have co-created a system that uses solar energy to split water molecules and hydrogen-eating bacteria to produce liquid fuels.

The paper, whose lead authors include post-doctoral fellow Chong Liu and graduate student Brendan Colón, is described in a June 3 paper published in Science.

“This is a true artificial photosynthesis system,” Nocera said. “Before, people were using artificial photosynthesis for water-splitting, but this is a true A-to-Z system, and we’ve gone well over the efficiency of photosynthesis in nature.”

While the study shows the system can be used to generate usable fuels, its potential doesn’t end there, said Silver, who is also a Founding Core Member of the Wyss Institute at Harvard University.

“The beauty of biology is it’s the world’s greatest chemist – biology can do chemistry we can’t do easily,” she said. “In principle, we have a platform that can make any downstream carbon-based molecule. So this has the potential to be incredibly versatile.”

Dubbed “bionic leaf 2.0,” the new system builds on previous work by Nocera, Silver and others, which – though it was capable of using solar energy to make isopropanol – faced a number of challenges.

Chief among those challenges, Nocera said, was the fact that the catalyst used to produce hydrogen – a nickel-molybdenum-zinc alloy – also created reactive oxygen species, molecules that attacked and destroyed the bacteria’s DNA. To avoid that problem, researchers were forced to run the system at abnormally high voltages, resulting in reduced efficiency.

“For this paper, we designed a new cobalt-phosphorous alloy catalyst, which we showed does not make reactive oxygen species,” Nocera said. “That allowed us to lower the voltage, and that led to a dramatic increase in efficiency.”

The system can now convert solar energy to biomass with 10 percent efficiency, Nocera said, far above the one percent seen in the fastest growing plants.

In addition to increasing the efficiency, Nocera and colleagues were able to expand the portfolio of the system to include isobutanol and isopentanol. Researchers also used the system to create PHB, a bio-plastic precursor, a process first demonstrated by MIT professor Anthony Sinskey.

The new catalyst also came with another advantage – its chemical design allows it to “self-heal” – meaning it wouldn’t leech material into solution.

“This is the genius of Dan,” Silver said. “These catalysts are totally biologically compatible.”

Though there may yet be room for additional increases in efficiency, Nocera said the system is already effective enough to consider possible commercial applications but within a different model for technology translation.

“It’s an important discovery–it says we can do better than photosynthesis,” Nocera said. “But I also want to bring this technology to the developing world as well.”

Working in conjunction with the First 100 Watts program at Harvard, which helped fund the research, Nocera hopes to continue developing the technology and its applications in nations like India with the help of their scientists.

In many ways, Nocera said, the new system marks the fulfillment of the promise of his “artificial leaf” – which used solar power to split water and make hydrogen fuel.

“If you think about it, photosynthesis is amazing,” he said. “It takes sunlight, water and air–and then look at a tree. That’s exactly what we did, but we do it significantly better, because we turn all that energy into a fuel.”



81 thoughts on “Bionic leaf turns sunlight into liquid fuel

    • Norcera’s philosophy is engineer for cost first.

      contempt prior to investigation

      • Well, I find myself in agreement with Mosher…

        Both cobalt and phosphorous are cheap, as are bacteria. No process of creating the gizmo can be horridly expensive given that solar cells are the benchmark competion and they are much harder to make than catalyst beds…

        This thing ought to be fairly cheap to make in quantity.

      • It will probably be so efficient that it will suck all of the CO2 out of the atmosphere. That will end our worries about CAGW for sure.

      • Leo.
        Nuclear doesn’t scale.
        You need to build a new plant every 1.5 days …Forever.

  1. It still relies on CO2 and will generate CO2, though. Can’t be good, can it?

    These types of technologies might hold the key for world energy in a few decades… assuming we do not manage to destroy the economies required to support them chasing a fraudulent scam.

  2. If I had to bet money, I’d bet against it taking over the energy market. Lots of things have been dreamed up, and they actually worked when they were scaled up, that never became commercial for various reasons. Remember “Oil from Turkey Guts”? It actually worked at a commercial scale. The problem was that they couldn’t get the turkey guts for free. There’s always something.

    • Well the Greenpiece high speed world circumnavigating record seeker boat that got sunk accidently by being run over by a Japanese whale science research vessel, was supposed to run on liposuction fat.
      Probably is a more dependable source of liposuction fat than turkey guts, specially in California. we have fatties galore here.


    • Not to mention that the efficiency and total cost of operation have to beat just pumping pre-made Gaia juice for fuel

  3. There are some very clever people around. Of course, plants do photosynthesis using only what is in the ground around them and what falls from the sky, they have the ability to self-replicate and they can evolve.

    I’m interested in this “new cobalt-phosphorous alloy catalyst”. I suspect mother nature has not been made redundant just yet.

    • Photosynthesis using only what is in the ground around them and what falls from the sky” not forgetting the chief ingredient for photosynthesis: Carbon Dioxide !

  4. ”We need grant money, we need grant money, we need…………………! Junior, quickly run off and get us another gross of gramophone needles!”

  5. …As someone said the other day..” 10X the efficiency at 100X the cost ” is not very helpful !

  6. Well, as a 3x Harvard grad, some perspectives. H is big into CAGW. They hired Naomi Oreskes, which has resulted in no contribs to any of the three schools by me, following the Cornell West precedent concerning my daughter (also a Harvard grad). Actions have consequences.

    SAES has had despite all that my indirect support since years. They previously announced the ‘rhubarb’ organic chemistry flow battery for intermittant renewable grid storage. I called horse manure. It apparently was just a hyped Ph.D thesis. Now this. I call horse manure again. For the same reasons. And SAES loses my indirect support. Horse manure is produced by horses, and does not need supplemental alumni financial support.

  7. This is likely to be a big game changer. The big stumbling block for bio fuels is the miserable efficiency of plants in turning CO2 into sugars. Upping the efficiency to 10% on their second try is fantastic result in bio-electrochemistry. Kudos to Dan Nocera the apparent brains behind the catalyst.

    • And that’s assuming an 18% conversion efficiency for the coupled solar cell. Running it on a 40-45% triple-junction, your output efficiency would be around 20%.

      • No because he took an engineering approach and understood that cost comes first, and the way to get cost down is to be something light and build millions.

        And because he saw the energy problem as a problem of providing more energy to poor people.

      • We will find new ways to make energy. This may be one. We have decades to figure it out given our fossil fuel reserves. Plus add in Nuclear. This is one option of many. Why discount any options at this time? Well, ok, I hate wind farms because I consider them visual pollution. But some may think they look ok and they don’t care about raptors and bats. Everything has a cost. And maybe a benefit.

        Thanks for the videos Mosher.

      • Mosher:
        “is to be something light and build millions.”
        Reminds me of Sapolsky I think. “They do it with a simple set of rules and a lot of ants.” Swarms.

    • Why does he speak of humans as if he is not one? He says “you” and not “us”.

  8. Yawn! Yet another bio-process which needs arable land already have beyond proof of concept production facilities for their continuous process which directly produces drop in designer hydrocarbons (Ethanol, Diesel, Gasoline). Put waste CO2 and dirty water in at one end, get pump ready fuel at the other at yields as high 20,000 litres/acre at costs as low as 17 cents a litre all from non arable land (e.g. mountains & desert), powered by sunshine.

    They even have an EPA certificate that says their products are both green (CO2 neutral) and compatible.

    Commercial grade plants will be producing more energy by the end of this decade annually using Joule Tech than Musk will ever store/distibute using lithium battery packs and all without a single $ of tax payers money.

    The only problem is that the Russians & the Arabs own the start up, primarily because Western investors have been scared off by eco-fundie activism.

  9. One little building block in a possible future bio-based economy. 10% is pretty impressive. Interesting stuff!

    • …10% efficiency is impressive ?..Wow, you must be really blown away by the efficiency of “Fossil Fuels” and nuclear ! D’oh !

    • I… think you’re not really getting what they did here. For that particular set of reactions a 10% overall efficiency is very high. Not sure why you would make these kind of unrelated but vaguely not nice comments.

  10. “It takes sunlight, water and air–…”

    Should be-

    It takes sunlight, water and carbon dioxide-…

  11. More efficient than photosynthesis. That means it’s 4-5% efficient?
    So you would need 4 to 5 times more surface area to produce the same amount of energy as an array of solar cells.
    Gee, there already isn’t enough land to plant all the solar cells needed, now they want 5 times more?

    • 10%, and they make hydrocarbons, not electricity, so you’d need to do a full LCA study to see how it stacks up to, say, making PV electricity and running an electric car with that. Too soon to do that with just some lab results.

  12. So many claims, so little evidence and data in the abstract.
    It is mostly the language of speculative hyperbole.

    Real advances covering multiple technologies just don’t happen as one sudden leap in one paper.
    If they have actually achieved a significant technical advance, then they should give real technical detail in the abstract, not flannel. As far as I can tell, they are just claiming another method of splitting water to Hydrogen and Oxygen using sunlight. You can already buy TiO2 that does that in Home Depot or many other garden centers. And you could mix that with Ralstonia eutropha and find that it also didn’t kill the bacteria.
    Woopity doo.

    The fact that they are talking in the speculative about it being “scalable”, and then claim efficiencies without even properly defining how efficiency was calculated, sets all my BS alarms clanging. And note the use of the word “would” in their extrapolations. I expect expect higher standards from Chemists than we commonly observe from climate scientists.

    • “So many claims, so little evidence and data in the abstract.”
      that is why it is called an “abstract”

      for science

      “Abstracts of Research Articles and Reports should explain to the general reader why the research was done, what was found and why the results are important. They should start with some brief BACKGROUND information: a sentence giving a broad introduction to the field comprehensible to the general reader, and then a sentence of more detailed background specific to your study. This should be followed by an explanation of the OBJECTIVES/METHODS and then the RESULTS. The final sentence should outline the main CONCLUSIONS of the study, in terms that will be comprehensible to all our readers. The Abstract is distinct from the main body of the text, and thus should not be the only source of background information critical to understanding the manuscript. Please do not include citations or abbreviations in the Abstract. The abstract should be 125 words or less. For Perspectives and Policy Forums please include a one-sentence abstract.”

    • Their first version

      I’ll leave you to criticize the MSU, MIT, Harvard, Chemists.

      you wont.

      See. you didnt even look at his research group. you didnt look through the publications.
      you rushed to comment and just said the first thing that came to your mind.


  13. To get commercial quantities of fuel you would have to use acreage the size of Iowa. That is a lot of PV cells! Also, years and years ago, before Scientific American was taken over by eco-loons, they published an article that concluded a healthy forest is 4% efficiency in converting sunlight to sugars (also known as wood.) His 10% is 2.5x better, not 10x better.

    • “Popular choices for plant biofuels include: oil palm, soybean, castor oil, sunflower oil, safflower oil, corn ethanol, and sugar cane ethanol.
      An analysis of a proposed Hawaiian oil palm plantation claimed to yield 600 gallons of biodiesel per acre per year. That comes to 2835 watts per acre or 0.7 W/m2.[8][irrelevant citation] Typical insolation in Hawaii is around 5.5 kWh/(m2day) or 230 watts.[9] For this particular oil palm plantation, if it delivered the claimed 600 gallons of biodiesel per acre per year, would be converting 0.3% of the incident solar energy to chemical fuel. Total photosynthetic efficiency would include more than just the biodiesel oil, so this 0.3% number is something of a lower bound.
      Contrast this with a typical photovoltaic installation,[10] which would produce an average of roughly 22 W/m2 (roughly 10% of the average insolation), throughout the year. Furthermore, the photovoltaic panels would produce electricity, which is a high-quality form of energy, whereas converting the biodiesel into mechanical energy entails the loss of a large portion of the energy. On the other hand, a liquid fuel is much more convenient for a vehicle than electricity, which has to be stored in heavy, expensive batteries.
      Most crop plants store ~0.25% to 0.5% of the sunlight in the product (corn kernels, potato starch, etc.), sugar cane is exceptional in several ways to yield peak storage efficiencies of ~8%.[citation needed]
      Ethanol fuel in Brazil has a calculation that results in: “Per hectare per year, the biomass produced corresponds to 0.27 TJ. This is equivalent to 0.86 W/m2. Assuming an average insolation of 225 W/m2, the photosynthetic efficiency of sugar cane is 0.38%.”

      Numbers vary.

      • Link, please. The last paragraph “Per hectare per year, the biomass produced corresponds to 0.27 TJ.” How does the biomass “correspond” to an energy? Do they use it for heating? Do they power a fuel cell? Do they burn it in a diesel engine? You could drive a truck through this hole.

        What might Prof. Nocera’s statement “the system can now convert solar energy to biomass with 10 percent efficiency” mean?

      • GIYF. I am not your personal librarian.
        If you have problems with Nocera’s claims, write a rebuttal to Science.
        let me know how that works for you.

      • Biofuels blow chunk. Palm oil is destroying the habitat of the orangutan, known to the Indonesians in their language as the “Jungle Man.” Ethanol from corn uses as much diesel as it replaces gasoline, and has more than doubled grain prices worldwide, nice for those 3rd Worlders who need something to eat they can afford. Ethanol from sugar cane is somewhat better but banned in the USA!

      • Mosher,

        I am about to flame you in an important way.

        This is absurd, congratulations for following this clown for years, But, he has Nothing.

        PV cells convert sunlight, at sunlight’s pathetically low flux, (do you know this word, Flux?) into Current, which is then converted into Voltage, which converts Water into Hydrogen and Oxygen. And all of this takes many many acres to do in any, any, any commercially significant way.


        This so-called “Bionic Leaf” has bacteria eating the hydrogen and excreting some sort of hydrocarbons, not Gasoline, not Diesel, but something which subsequently, by some other rather expensive processes, could be converted into a useful Fuel. You must research this word, Fuel, it means something that an Engine can Use.

        And, the catalysts are horribly toxic, let’s talk about cobalt.

        I repeat my earlier comment, “Ardent but Un-Schooled.”

        But you keep it up, let us see what you come up with next…

      • What kills the efficiency of biofuels is the FARMING. Large energy inputs from diesel for production and transportation yield net negative energy balances in many cases. The beauty of this is the fuel can stay local. Like having solar panels on your roof that power your car. Folks driving Teslas powered by the grid pat their own backs ignoring 30% transmission losses through the grid.

  14. Not to be a bed wetter here but these catalytic compounds are fairly dangerous, heavy metal halides and the like. Does anybody have a plan for recovering these metals at the end of the system’s life or are we going to have another nationwide emergency like we had in the 1970s with lead halides being used to tint paint? I’ve been asking the same questions in regards to the batteries used in cars and the like too.

    It’s bad enough that we have “disposable” batteries going into land fills now. Not that I’m a big time tree hugger or anything but these metals in the forms they’re being used are big time bad news.

  15. Blah, blah, blah…..ok, how about some actual science here….as in independent replication.

    • read their first paper. they give lab instructions.
      go test it.
      The Air Force seemed happy with their first paper ( achieved 3.2%)
      but what do the defenders of freedom know.

      • The Us military know they must say yes to every dumb request from the President, otherwise they will be fired, as many Generals have already experienced. This includes wasting defense budget money to run the Fleet on biofuels at $26/gallon and even more purchasing it from a corporate crony who got tax dollars to build the plant. This while the military cannot purchase parts to repair critical equipment due to funding cuts.

  16. “The system can now convert solar energy to biomass with 10 percent efficiency, Nocera said, far above the one percent seen in the fastest growing plants… In many ways, Nocera said, the new system marks the fulfillment of the promise of his “artificial leaf” – which used solar power to split water and make hydrogen fuel.”

    This system is inferior to present solar PV and electrolyzer technologies. The most efficient PV cell has attained 46% efficiency. A rotating electrolyzer has attained 79% efficiency. Combined the overall efficiency is 36%. This is all you need to use sunlight to split water and make hydrogen fuel.

  17. I checked.Its not April 1

    we’ve had high altitude kites, space solar panels and now bionic leaves.

    since AGW is not happening, there s no real point in hugely expensive alternatives to fossil fuels, especially when we already have nuclear.

    even if these leaves produced high grade diesel at 100% efficiency, there isnt enough sunlight falling on the land that has the water to grow the food AND the fuel.

    And if the population of the world continues to grow and wants a western lifestyle, there isn’t enough energy in the sunlight arriving, in toto.

    what’s up with watts up with that?

    I don’t come here to read the National Geographic.

  18. More efficient than plants they say, since when do plants have to spend millions and years to do what they do, they do it and reproduce themselves quite easily and rapidly without any input from humans.

    I get jaded reading such things, they are at this donkeys years and still have not produced a useful product.
    Forgive me for being a little suspicious of an oversell.

    Plants are not inefficient, they use what they need not more than, more converted energy would need more water more CO2 more nutrients. If plants would work at 10%, would there be any minerals left in soil by now?

    Bleh, wake me up when they actually change something with this

  19. Interesting abstract, it sounds as if it’s worth taking to the pilot plant stage. If it turns out to be cost effective and doesn’t pollute too much, it could end up coming to the market.

    I can’t quite understand the rather negative tone of most of the comments here. The concept of producing renewable liquid fuel without wasting what would otherwise be food, and without turning forests into monocultures, seems like a worthwhile objective that is independent of what you might think about CO2 and global warming. If it ends up not being practical at commercial scales, it will fade away, without the need for scorn from the sceptical side of the fence.

    Unless of course it turns out to be uneconomical at the commercial scale but still gets enough press coverage that it’s foisted on the world by those who would tell us how to live, Save your venom for that day, please.

    Meanwhile, I think I’ll get on to reading more posts for my amusement and/or education. Nothing more to learn here.

  20. I hope this works. The comments could have been much better if we were given more numbers. For this area of light collecting surface and this much catalyst (currently costing x) we obtained so-much this, this-much that, etc per day at where. Many readers suspect the lack of numbers means the numbers are not good, for surely those good scientists record the numbers.

  21. Nocera said the system is already effective enough to consider possible commercial applications but within a different model for technology translation. Does this make sense to anyone?

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