Artificial leaves could use sunlight to produce hydrogen fuel for cars and power plants.
Image: Cherie Sinnen
In Brief
- Natural energy: Plants produce their own chemical fuel—sugar—from sunlight, air and water, without producing harmful emissions.
- Man-made leaf: Researchers are devising artificial leaves that could similarly convert sunlight and water into hydrogen fuel, which could be burned to power cars, create heat or generate electricity, ending dependence on fossil fuels.
- Nano solution: To be practical, this solar-fuel technology would have to be made cheaply in thin, flexible sheets, perhaps from silicon nanowires, and use inexpensive catalysts that help to generate hydrogen efficiently.
More In This Article
Like a fire-and-brimstone preacher, Nathan S. Lewis has been giving a lecture on the energy crisis that is both terrifying and exhilarating. To avoid potentially debilitating global warming, the chemist from the California Institute of Technology says civilization must be able to generate more than 10 trillion watts of clean, carbon-free energy by 2050. That level is three times the U.S.’s average energy demand of 3.2 trillion watts. Damming up every lake, stream and river on the planet, Lewis notes, would provide only five trillion watts of hydroelectricity. Nuclear power could manage the feat, but the world would have to build a new reactor every two days for the next 50 years.
Before Lewis’s crowds get too depressed, he tells them there is one source of salvation: the sun pours more energy onto the earth every hour than humankind uses in a year. But to be saved, Lewis says, humankind needs a radical breakthrough in solar-fuel technology: artificial leaves that will capture solar rays and churn out chemical fuel on the spot, much as plants do. We can burn the fuel, as we do oil or natural gas, to power cars, create heat or generate electricity, and we can store the fuel for use when the sun is down.
This article was originally published with the title Reinventing the Leaf.
Already a Digital subscriber? Sign-in Now
If your institution has site license access, enter here.
Rights & Permissions
See what we're tweeting about
16 Comments
Add CommentWhat was the point of this article? A suggestion that 'synthetic photosynthesis' is the answer to all our problems? There's not even any hint here of any technological approach. In the past I have read articles that refer to highly questionable approaches...
Reply | Report Abuse | Link to thisThe devil is in the details. I get tired of polyanish wish lists of 'clean and cheap' energy.
Reply | Report Abuse | Link to thisIt's a teaser. The patient will wait for their paper mag to land in the mailbox, the others will pay for the digital file.
Reply | Report Abuse | Link to thisI'm one of the patient. Being a subscriber helps...
Once upon a time, this paper had real science articles, with references to published papers and explaining actual scientific advances...
Reply | Report Abuse | Link to thisErroneous! Human technology will not save the planet from its death, only the fall cf industrial civilization will. This just a way for us the say the future will be better and do nothing about it.
Reply | Report Abuse | Link to thisactually, a piece of wood is mostly made of carbon and photon energy, therefore, if we can tap on that photon and carbon before they turn into wood, we can have some energy and reduce carbon in the air. however, as far as i know energy captured by a leaf does not have enough density, therefore we should have a lot of leaves, which might be costly to built.
Reply | Report Abuse | Link to thisPhiolpeantube, I can only point out that while we had less impact with a smaller population, the impact per capita might actually be worse without tech. As bad as cars are, imagine the impact on food supplies and manure accumulation of everyone having a horse instead. Admittedly, your drop in technology would result in untreated water systems and a loss of simple antibiotics, so the world's overpopulation problem would no longer be a problem. Sounds good unless you are the one being depopulated. It's good to have a good facetious jab at the trappings of our technological world now and again, but I see solutions as requiring more technology, not less. Think a green roof is good because it is low tech? Think again. Low tech green roofs leak.
Reply | Report Abuse | Link to thisThanks again - I missed the 'buy more' button as well as the 'supplemental material', although I can't recommend it.
Reply | Report Abuse | Link to thisCarbon dioxide works very efficiently in a laser. Using the gas to harness solar energy is easy by simply exciting the gas with sunlight, and then using the laser beam to generate electricity more efficiently.
Reply | Report Abuse | Link to thisCarbon dioxide is very transparent to infrared light except at 15 microns. The gas absorbs all light at 15 microns. The gas has no effect on climate because more carbon dioxide cannot absorb more light since all light at 15 microns is already absorbed.
Sun is past,present and future source of all energies on earth. So this may be most plausible idea of energy beyond oil age and apart from efficient nuclear energy. but the idea of artificial leaf build chemical fuel on the spot seems unrealistic and mere a imagination. Like photosynthesis stores the energy in phosphate bonds of ATP,which can be utilized by breaking the bond,a artificial battery may store energy from sun by fixing some carbon. But it is nearly impossible to bring about the degree of precision in the enzymatic and genetic control as happening in living systems.Instead what is possible is to invent high efficient solar panels which can trap the total energy falling on it.A solar tree may be imagined with solar panels in the fashion of small or big leaves to maximize the absorption. every household may have one or two such trees to be self sufficient in energy.
Reply | Report Abuse | Link to thisI like the idea of a solar-panel tree. I have often thought that if we could fill the Sahara and other deserts with solar panels, we could kill two birds with one stone. You can provide clean energy for humans, absorb and use energy which is currently just going to heat the planet, and if they were elevated like trees, provide shade to help make the ground livable in the desert again. With enough shade, maybe enough water would stick around to allow real life to enter back into the region. Sand storms would dump a lot of sand on your panels initially, more or less fighting your ability to make a profit from the energy unless you hired people to keep them clean. If these solar panel trees could grow like real trees and use a continuous network of "roots" to wire themselves in a fashion to allow people to tap into the energy, eventually the roots themselves would help stop the soil erosion that causes sandstorms in the first place. The only challenges are getting the silicon pure enough and designing the system to be self assembling without any source of water. (Incidentally, if they also grow without air too, we could use these on the moon as well.) The purity issue that is so expensive to achieve using the techniques we are now that setting up this forest would be a hugely expensive proposition. If the replication mechanism were operating at the molecular level in the first place, however, this sort of purity might come naturally. That leaves us with the challenge of figuring out how to bio-engineer a silicate based chemical processes. It falls right below carbon in the periodic table, so you would think it would lend itself to fantastically complex chemical arrangements that could mimic the function of proteins, enzymes etc. The problem is that most of our carbon-based chemical process doesn't happen unless suspended in water. I can't think of what we could suspend silicon chemistry in that would allow for complex auto-assembly, but then I'm no chemist. I suspect that whatever it is will be horribly toxic, expensive to manufacture, and strictly unavailable either in a desert or on the moon. But presuming I'm wrong about that, I see real potential in solar panel trees.
Reply | Report Abuse | Link to thisYou people are right this research is completely fake and is wasting 135 million in research grant money plus an unknown amount of venture capital. The real deal is here http://photoengineering.org where the research was stolen.
Reply | Report Abuse | Link to thisEvolution has spent billions of years perfecting the leaf. Leaves absorb CO2 in the air from fossil fuels. Pyrolyse the biomass or hydrocarbons and you get solid carbon and hydrogen. Put the carbon in landfill and so no need for CO2 CCS. Burn the hydrogen and the only waste is pure water. Let nature convert CO2 cheaply and cleanly, and let pyrolysis convert our dirty old carbon-based economy into a sustainable hydrogen-based one.
Reply | Report Abuse | Link to thisI agree with Philopeantube it is true that human technology is not enough to improve the world and it is too late to do anything to help it.
Reply | Report Abuse | Link to thisThe suggestion of a solar tree with manmade solar panelitic photosynthesis producing leaves is most stunningly creative and intriguing. I can imagine every yard having one or two that would provide all galvanic power needed for living quarters and stored in battery-like boxes for powering automobiles, trucks, etc. And if different sizes were made available how aesthetic it would look as well. Now that is a future worth thinking about.
Reply | Report Abuse | Link to thisI've always thought though that all new designed automobiles ought to have roofs made of solar panels that would convert sun energy into direct use to power mobility or stored in cells for nighttime use. The trick will be to find material that holds enough energy to last through the night, especially if one were traveling at night. And when wheeless vehicles are invented, i.e., hovercraft for popular use, solar energy would also be used. What a clean world it would be!
Wonderful thinking! I would only say that power forests as large as the Sahara would not be necessary if every residence and business had such power trees as part of its landscape. Manufacturing factories could have its own power woods on its property. Even if there is no land to speak of, these "trees" could be part of the external architecture planning where sunlight is available. Even part of the building itself or on roofs. All kinds of configurations are possible. The application would be endless. Human ingenuity is amazingly inventive. Sun power would be available until the solar system vanished. The entire idea manifested would show that humans could actually live symbiotically with nature.
Reply | Report Abuse | Link to this