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  • richardmitnick 8:21 am on September 8, 2018 Permalink | Reply
    Tags: , Artificial photosynthesis, , , , , , Hydrogenase is an enzyme present in algae that is capable of reducing protons into hydrogen, Natural photosynthesis, , Scientists pioneer a new way to turn sunlight into fuel, Solar energy conversion, St. Johns College at Cambridge,   

    From University of Cambridge: “Scientists pioneer a new way to turn sunlight into fuel” 

    U Cambridge bloc

    From University of Cambridge

    03 Sep 2018
    No writer credit

    The quest to find new ways to harness solar power has taken a step forward after researchers successfully split water into hydrogen and oxygen by altering the photosynthetic machinery in plants.

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    Experimental two-electrode setup showing the photoelectrochemical cell illuminated with simulated solar light. Credit: Katarzyna Sokół

    Photosynthesis is the process plants use to convert sunlight into energy. Oxygen is produced as a by-product of photosynthesis when the water absorbed by plants is ‘split’. It is one of the most important reactions on the planet because it is the source of nearly all of the world’s oxygen. Hydrogen which is produced when the water is split could potentially be a green and unlimited source of renewable energy.

    A new study led by academics at the University of Cambridge, used semi-artificial photosynthesis to explore new ways to produce and store solar energy. They used natural sunlight to convert water into hydrogen and oxygen using a mixture of biological components and manmade technologies.

    The research could now be used to revolutionise the systems used for renewable energy production. A new paper, published in [Nature Energy], outlines how academics at the Reisner Laboratory in Cambridge’s Department of Chemistry developed their platform to achieve unassisted solar-driven water-splitting.

    Their method also managed to absorb more solar light than natural photosynthesis.

    Katarzyna Sokół, first author and PhD student at St John’s College, said: “Natural photosynthesis is not efficient because it has evolved merely to survive so it makes the bare minimum amount of energy needed – around 1-2 per cent of what it could potentially convert and store.”

    Artificial photosynthesis has been around for decades but it has not yet been successfully used to create renewable energy because it relies on the use of catalysts, which are often expensive and toxic. This means it can’t yet be used to scale up findings to an industrial level.

    The Cambridge research is part of the emerging field of semi-artificial photosynthesis which aims to overcome the limitations of fully artificial photosynthesis by using enzymes to create the desired reaction.

    Sokół and the team of researchers not only improved on the amount of energy produced and stored, they managed to reactivate a process in the algae that has been dormant for millennia.

    She explained: “Hydrogenase is an enzyme present in algae that is capable of reducing protons into hydrogen. During evolution, this process has been deactivated because it wasn’t necessary for survival but we successfully managed to bypass the inactivity to achieve the reaction we wanted – splitting water into hydrogen and oxygen.”

    Sokół hopes the findings will enable new innovative model systems for solar energy conversion to be developed.

    She added: “It’s exciting that we can selectively choose the processes we want, and achieve the reaction we want which is inaccessible in nature. This could be a great platform for developing solar technologies. The approach could be used to couple other reactions together to see what can be done, learn from these reactions and then build synthetic, more robust pieces of solar energy technology.”

    This model is the first to successfully use hydrogenase and photosystem II to create semi-artificial photosynthesis driven purely by solar power.

    Dr Erwin Reisner, Head of the Reisner Laboratory, a Fellow of St John’s College, University of Cambridge, and one of the paper’s authors described the research as a ‘milestone’.

    He explained: “This work overcomes many difficult challenges associated with the integration of biological and organic components into inorganic materials for the assembly of semi-artificial devices and opens up a toolbox for developing future systems for solar energy conversion.”

    See the full article here .

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    The University of Cambridge (abbreviated as Cantab in post-nominal letters) is a collegiate public research university in Cambridge, England. Founded in 1209, Cambridge is the second-oldest university in the English-speaking world and the world’s fourth-oldest surviving university. It grew out of an association of scholars who left the University of Oxford after a dispute with townsfolk. The two ancient universities share many common features and are often jointly referred to as “Oxbridge”.

    Cambridge is formed from a variety of institutions which include 31 constituent colleges and over 100 academic departments organised into six schools. The university occupies buildings throughout the town, many of which are of historical importance. The colleges are self-governing institutions founded as integral parts of the university. In the year ended 31 July 2014, the university had a total income of £1.51 billion, of which £371 million was from research grants and contracts. The central university and colleges have a combined endowment of around £4.9 billion, the largest of any university outside the United States. Cambridge is a member of many associations and forms part of the “golden triangle” of leading English universities and Cambridge University Health Partners, an academic health science centre. The university is closely linked with the development of the high-tech business cluster known as “Silicon Fen”.

     
  • richardmitnick 12:50 pm on July 18, 2018 Permalink | Reply
    Tags: , Artificial photosynthesis, Francesca Toma, Johanna Eichhorn, , , Splitting Water: Nanoscale Imaging Yields Key Insights,   

    From Lawrence Berkeley National Lab: Women in STEM- “Splitting Water: Nanoscale Imaging Yields Key Insights” Francesca Toma and Johanna Eichhorn 

    Berkeley Logo

    From Lawrence Berkeley National Lab

    July 18, 2018
    Julie Chao
    JHChao@lbl.gov
    (510) 486-6491

    1
    Berkeley Lab researchers Francesca Toma (left) and Johanna Eichhorn used a photoconductive atomic force microscope to better understand materials for artificial photosynthesis. (Credit: Marilyn Chung/Berkeley Lab)

    In the quest to realize artificial photosynthesis to convert sunlight, water, and carbon dioxide into fuel – just as plants do – researchers need to not only identify materials to efficiently perform photoelectrochemical water splitting, but also to understand why a certain material may or may not work. Now scientists at Lawrence Berkeley National Laboratory (Berkeley Lab) have pioneered a technique that uses nanoscale imaging to understand how local, nanoscale properties can affect a material’s macroscopic performance.

    Their study, Nanoscale Imaging of Charge Carrier Transport in Water Splitting Anodes, has just been published in Nature Communications. The lead researchers were Johanna Eichhorn and Francesca Toma of Berkeley Lab’s Chemical Sciences Division.

    “This technique correlates the material’s morphology to its functionality, and gives insights on the charge transport mechanism, or how the charges move inside the material, at the nanoscale,” said Toma, who is also a researcher in the Joint Center for Artificial Photosynthesis, a Department of Energy Innovation Hub.

    Artificial photosynthesis seeks to produce energy-dense fuel using only sunlight, water, and carbon dioxide as inputs. The advantage of such an approach is that it does not compete against food stocks and would produce no or low greenhouse gas emissions. A photoelectrochemical water splitting system requires specialized semiconductors that use sunlight to split water molecules into hydrogen and oxygen.

    Bismuth vanadate has been identified as a promising material for a photoanode, which provides charges to oxidize water in a photoelectrochemical cell. “This material is a case example in which efficiency should be theoretically good, but in experimental tests you actually observe very poor efficiency,” Eichhorn said. “The reasons for that are not completely understood.”

    The researchers used photoconductive atomic force microscopy to map the current at every point of the sample with high spatial resolution. This technique has already been used to analyze local charge transport and optoelectronic properties of solar cell materials but is not known to have been used to understand the charge carrier transport limitations at the nanoscale in photoelectrochemical materials.

    Eichhorn and Toma worked with scientists at the Molecular Foundry, a nanoscale science research facility at Berkeley Lab, on these measurements through the Foundry’s user program. They found that there were differences in performance related to the nanoscale morphology of the material.

    “We discovered that the way charges are utilized is not homogeneous over the whole sample, but rather, there’s heterogeneity,” Eichhorn said. “Those differences in performance may account for its macroscopic performance – the overall output of the sample – when we perform water splitting.”

    To understand this characterization, Toma gives the example of a solar panel. “Let’s say the panel has 22 percent efficiency,” she said. “But can you tell at the nanoscale, at each point in the panel, that it will give you 22 percent efficiency? This technique enables you to say, yes or no, specifically for photoelectrochemical materials. If the answer is no, it means there are less active spots on your material. In the best case it just decreases your total efficiency, but if there are more complex processes, your efficiency can be decreased by a lot.”

    The improved understanding of how the bismuth vanadate is working will also allow researchers to synthesize new materials that may be able to drive the same reaction more efficiently. This study builds on previous research by Toma and others, in which she was able to analyze and predict the mechanism that defines (photo)chemical stability of a photoelectrochemical material.

    Toma said these results put scientists much closer to achieving efficient artificial photosynthesis. “Now we know how to measure local photocurrent in these materials, which have very low conductivity,” she said. “The next step is to put all of this in a liquid electrolyte and do exactly the same thing. We have the tools. Now we know how to interpret the results, and how to analyze them, which is an important first step for moving forward.”

    Other co-authors of the study were Christoph Kastl, Jason Cooper, Adam Schwartzberg, and Ian Sharp (now at the Technical University of Munich) of Berkeley Lab; and Dominik Ziegler of Scuba Probe Technologies, a startup company and Molecular Foundry user. The research was funded by Berkeley Lab’s Laboratory Directed Research and Development program (LDRD). The Molecular Foundry is a Department of Energy Office of Science User Facility.

    See the full article here .


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  • richardmitnick 4:20 pm on October 6, 2017 Permalink | Reply
    Tags: , Artificial photosynthesis, , , The end goal is to break out those molecular building blocks—the protons and electrons—to make fuels such as hydrogen   

    From BNL: “New Efficient Catalyst for Key Step in Artificial Photosynthesis” 

    Brookhaven Lab

    October 3, 2017
    Karen McNulty Walsh
    kmcnulty@bnl.gov
    (631) 344-8350

    Peter Genzer,
    genzer@bnl.gov
    (631) 344-3174

    Process sets free protons and electrons that can be used to make fuels.

    1
    Research team leader Javier Concepcion (standing, left) with Yan Xie, David Shaffer, and David Szalda

    Chemists at the U.S. Department of Energy’s Brookhaven National Laboratory have designed a new catalyst that speeds up the rate of a key step in “artificial photosynthesis”—an effort to mimic how plants, algae, and some bacteria harness sunlight to convert water and carbon dioxide into energy-rich fuels. This step—called water oxidation—releases protons and electrons from water molecules, producing oxygen as a byproduct.

    This “single-site” catalyst—meaning the entire reaction sequence takes place on a single catalytic site of one molecule—is the first to match the efficiency of the catalytic sites that drive this reaction in nature. The single-site design and high efficiency greatly improve the potential for making efficient solar-to-fuel conversion devices.

    “The end goal is to break out those molecular building blocks—the protons and electrons—to make fuels such as hydrogen,” said David Shaffer, a Brookhaven research associate and lead author on a paper describing the work in the Journal of the American Chemical Society. “The more efficient the water oxidation cycle is, the more energy we can store.”

    But breaking apart water molecules isn’t easy.

    “Water is very stable,” said Brookhaven chemist Javier Concepcion, who led the research team. “Water can undergo many boiling/condensing cycles and it stays as H2O. To get the protons and electrons out, we need to make the water molecules react with each other.”

    The catalyst acts as a chemical handler, shuffling around the water molecules’ assets—electrons, hydrogen ions (protons), and oxygen atoms—to get the reaction to happen.


    Bubbles indicate the rapid production of oxygen (O2) when the catalyst is added to the solution. For each O2 molecule produced, four protons (H+) and four electrons are released—enough to make two hydrogen (H2) molecules. No video credit.

    The new catalyst design builds on one the group developed last year, led by graduate student Yan Xie, which was also a single-site catalyst, with all the components needed for the reaction on a single molecule. This approach is attractive because the scientists can optimize how the various parts are arranged so that reacting molecules come together in just the right way. Such catalysts don’t depend on the free diffusion of molecules in a solution to achieve reactions, so they tend to continue functioning even when fixed to a surface, as they would be in real-world devices.

    “We used computer modeling to study the reactions at the theoretical level to help us design our molecules,” Concepcion said. “From the calculations we have an idea of what will work or not, which saves time before we get into the lab.”

    In both Xie’s design and the new improvement, there’s a metal at the core of the molecule, surrounded by other components the scientists can choose to give the catalyst particular properties. The reaction starts by oxidizing the metal, which pulls electrons away from the oxygen on a water molecule. That leaves behind a “positively charged,” or “activated,” oxygen and two positively charged hydrogens (protons).

    “Taking electrons away makes the protons easier to release. But you need those protons to go somewhere. And it’s more efficient if you remove the electrons and protons at the same time to prevent the build-up of excess charges,” Concepcion said. “So Xie added phosphonate groups as ligands on the metal to act as a base that would accept those protons,” he explained. Those phosphonate groups also made it easier to oxidize the metal to remove the electrons in the first place.

    But there was still a problem. In order to activate the H2O molecule, you first need it to bind to the metal atom at the center of the catalyst.

    In the first design, the phosphonate groups were so strongly bound to the metal that they were preventing the water molecule from binding to the catalyst early enough to keep the process running smoothly. That slowed the catalytic cycle down.

    So the team made a substitution. They kept one phosphonate group to act as the base, but swapped out the other for a less-tightly-bound carboxylate.

    “The carboxylate group can more easily adjust its coordination to the metal center to allow the water molecule to come in and react at an earlier stage,” Shaffer said.

    “When we are trying to design better catalysts, we first try to figure out what is the slowest step. Then we redesign the catalyst to make that step faster,” he said. “Yan’s work made one step faster, and that made one of the other steps end up being the slowest step. So in the current work we accelerated that second step while keeping the first one fast.”

    The improvement transformed a catalyst that created two or three oxygen molecules per second to one that produces more than 100 per second—with a corresponding increase in the production of protons and electrons that can be used to create hydrogen fuel.

    2
    The new catalyst has a ruthenium (Ru) atom at its core, a “pendant” phosphonate group to act as a base that accepts protons (H+) from water, and a more flexible, or “labile,” carboxylate group that facilitates the interaction of the catalyst with water. No image credit.

    “That’s a rate that is comparable to the rate of this reaction in natural photosynthesis, per catalytic site,” Concepcion said. “The natural photosynthesis catalyst has four metal centers and ours only has one,” he explained. “But the natural system is very complex with thousands and thousands of atoms. It would be extremely hard to replicate something like that in the lab. This is a single molecule and it does the same function as that very complex system.”

    The next step is to test the new catalyst in devices incorporating electrodes and other components for converting the protons and electrons to hydrogen fuel—and then later, with light-absorbing compounds to provide energy to drive the whole reaction.

    “We have now systems that are working quite well, so we are very hopeful,” Concepcion said.

    This work was supported by the DOE Office of Science.

    Scientific paper: Lability and Basicity of Bipyridine-Carboxylate-Phosphonate Ligand Accelerate Single-Site Water Oxidation by Ruthenium-Based Molecular Catalysts JACS

    See the full article here .

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    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
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  • richardmitnick 5:43 pm on June 2, 2016 Permalink | Reply
    Tags: , Artificial photosynthesis, Bionic Leaf Makes Fuel from Sunlight Water and Air,   

    From SA: “Bionic Leaf Makes Fuel from Sunlight, Water and Air” 

    Scientific American

    Scientific American

    June 2, 2016
    David Biello

    A new device that combines chemistry and synthetic biology could prove key to renewable fuels and even chemicals—and combating climate change.

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    The device uses solar electricity from a photovoltaic panel to power the chemistry that splits water into oxygen and hydrogen, then adds pre-starved microbes to feed on the hydrogen and convert CO2 in the air into alcohol fuels. Credit: Des_Callaghan via Wikimedia Commons

    A tree’s leaf, a blade of grass, a single algal cell: all make fuel from the simple combination of water, sunlight and carbon dioxide through the miracle of photosynthesis. Now scientists say they have replicated—and improved—that trick by combining chemistry and biology in a “bionic leaf.”

    Chemist Daniel Nocera of Harvard University and his team joined forces with synthetic biologist Pamela Silver of Harvard Medical School and her team to craft a kind of living battery, which they call a bionic leaf for its melding of biology and technology. The device uses solar electricity from a photovoltaic panel to power the chemistry that splits water into oxygen and hydrogen, then adds pre-starved microbes to feed on the hydrogen and convert CO2 in the air into alcohol fuels. The team’s first artificial photosynthesis device appeared in 2015—pumping out 216 milligrams of alcohol fuel per liter of water—but the nickel-molybdenum-zinc catalyst that made its water-splitting chemistry possible had the unfortunate side effect of poisoning the microbes.

    So the team set out in search of a better catalyst, one that would play well with living organisms while effectively splitting water. As the team reports* in Science on June 2, they found it in an alloy of cobalt and phosphorus, an amalgam already in use as an anti-corrosion coating for plastic and metal parts found in everything from faucets to circuit boards. With a little charge this new catalyst can assemble itself out of a solution of regular water, cobalt and phosphate—and phosphate in water actually is good for living things like the Ralstonia eutropha bacteria that make up the back half of the bionic leaf. Run an electric current from a photovoltaic device through this solution at a high enough voltage and it splits water. That voltage is also higher than what is needed to induce the cobalt to precipitate out of the solution and form the cobalt phosphide catalyst, which means when the bionic leaf is running there are always enough electrons around to induce the catalyst’s formation—and therefore no excess metal left to poison the microbes or bring the bionic leaf’s water-splitting to a halt. “The catalyst can never die as it’s functioning,” Nocera says, noting that the new artificial leaf has been able to run for up to 16 days at a stretch.

    The new cobalt catalyst also splits water into hydrogen and oxygen without creating the kind of reactive oxygen molecules that can damage DNA or other processes essential to continuing life. “I don’t know why yet,” Nocera says. “That will be fun to figure out.”

    With this new catalyst in the bionic leaf, the team boosted version 2.0’s efficiency at producing alcohol fuels like isopropanol and isobutanol to roughly 10 percent. In other words, for every kilowatt-hour of electricity used the microbes could scrub 130 grams of CO2 out of 230,000 liters of air to make 60 grams of isopropanol fuel. That is better than the efficiency of natural photosynthesis at converting water, sunlight and air into stored energy.

    And there is no reason to think that the R. eutropha could not be made to generate other products—perhaps complex hydrocarbon molecules like those found in fossil fuels, or even the whole range of chemicals currently synthesized from polluting resources, such as fertilizers. “You have bugs that eat hydrogen as their only food source, and the hydrogen came from solar energy water splitting. So you have renewable bugs and the synthetic biology to make them do anything,” Nocera says. “You can start thinking about a renewable chemicals industry.” The hybrid team reports in the paper in Science that they have already induced R. eutropha to make a molecule that can ultimately be transformed into plastics.

    The fundamental idea is to reverse combustion and use a remnant of fossil fuel burning—the CO2 piling up in the atmosphere—to build renewable fuels, just as plants do. But the bionic leaf will not compete on price at any time soon with the fossil fuels dug out of the ground, especially since the microbes do not yet make a lot of fuel quickly. The largest bionic leaf to date is in a one-liter pot, though the team has not discovered any limits to making it bigger.

    By knitting fuels out of the excess CO2 in the air, this new bioreactor could help mitigate planet-warming pollution problems while bringing cleaner fuels to people who do not currently have access to modern energy. “This science you can do in your backyard. You don’t need a multi-billion dollar massive infrastructure,” Nocera says.

    “By integrating the technology of biology and organic chemistry there is a very powerful path forward where you take the best of both worlds,” he adds. “I took air plus sunlight plus water and I made stuff out of it, and I did it 10 times better than nature. That makes me feel good.”

    *Science paper:
    Water splitting–biosynthetic system with CO2 reduction efficiencies exceeding photosynthesis

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  • richardmitnick 2:28 pm on August 27, 2015 Permalink | Reply
    Tags: , Artificial photosynthesis,   

    From Caltech: “Artificial Leaf Harnesses Sunlight for Efficient Fuel Production” 

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    Caltech

    08/27/2015
    Jessica Stoller-Conrad

    1
    (From left to right): Chengxiang Xiang and Erik Verlage assemble a monolithically integrated III-V device, protected by a TiO2 stabilization layer, which performs unassisted solar water splitting with collection of hydrogen fuel and oxygen.
    Credit: Lance Hayashida/Caltech

    A highly efficient photoelectrochemical (PEC) device uses the power of the sun to split water into hydrogen and oxygen. The stand-alone prototype includes two chambers separated by a semi-permeable membrane that allows collection of both gas products.
    Credit: Lance Hayashida/Caltech
    3
    Illustration of an efficient, robust and integrated solar-driven prototype featuring protected photoelectrochemical assembly coupled with oxygen and hydrogen evolution reaction catalysts. [View full size]
    Credit: Image provided courtesy of Joint Center for Artificial Photosynthesis; artwork by Darius Siwek

    Generating and storing renewable energy, such as solar or wind power, is a key barrier to a clean-energy economy. When the Joint Center for Artificial Photosynthesis (JCAP) was established at Caltech and its partnering institutions in 2010, the U.S. Department of Energy (DOE) Energy Innovation Hub had one main goal: a cost-effective method of producing fuels using only sunlight, water, and carbon dioxide, mimicking the natural process of photosynthesis in plants and storing energy in the form of chemical fuels for use on demand. Over the past five years, researchers at JCAP have made major advances toward this goal, and they now report the development of the first complete, efficient, safe, integrated solar-driven system for splitting water to create hydrogen fuels.

    “This result was a stretch project milestone for the entire five years of JCAP as a whole, and not only have we achieved this goal, we also achieved it on time and on budget,” says Caltech’s Nate Lewis, George L. Argyros Professor and professor of chemistry, and the JCAP scientific director.

    The new solar fuel generation system, or artificial leaf, is described in the August 27 online issue of the journal Energy and Environmental Science. The work was done by researchers in the laboratories of Lewis and Harry Atwater, director of JCAP and Howard Hughes Professor of Applied Physics and Materials Science.

    “This accomplishment drew on the knowledge, insights and capabilities of JCAP, which illustrates what can be achieved in a Hub-scale effort by an integrated team,” Atwater says. “The device reported here grew out of a multi-year, large-scale effort to define the design and materials components needed for an integrated solar fuels generator.”

    The new system consists of three main components: two electrodes—one photoanode and one photocathode—and a membrane. The photoanode uses sunlight to oxidize water molecules, generating protons and electrons as well as oxygen gas. The photocathode recombines the protons and electrons to form hydrogen gas. A key part of the JCAP design is the plastic membrane, which keeps the oxygen and hydrogen gases separate. If the two gases are allowed to mix and are accidentally ignited, an explosion can occur; the membrane lets the hydrogen fuel be separately collected under pressure and safely pushed into a pipeline.

    Semiconductors such as silicon or gallium arsenide absorb light efficiently and are therefore used in solar panels. However, these materials also oxidize (or rust) on the surface when exposed to water, so cannot be used to directly generate fuel. A major advance that allowed the integrated system to be developed was previous work in Lewis’s laboratory, which showed that adding a nanometers-thick layer of titanium dioxide (TiO2)—a material found in white paint and many toothpastes and sunscreens—onto the electrodes could prevent them from corroding while still allowing light and electrons to pass through. The new complete solar fuel generation system developed by Lewis and colleagues uses such a 62.5-nanometer-thick TiO2 layer to effectively prevent corrosion and improve the stability of a gallium arsenide–based photoelectrode.

    Another key advance is the use of active, inexpensive catalysts for fuel production. The photoanode requires a catalyst to drive the essential water-splitting reaction. Rare and expensive metals such as platinum can serve as effective catalysts, but in its work the team discovered that it could create a much cheaper, active catalyst by adding a 2-nanometer-thick layer of nickel to the surface of the TiO2. This catalyst is among the most active known catalysts for splitting water molecules into oxygen, protons, and electrons and is a key to the high efficiency displayed by the device.

    The photoanode was grown onto a photocathode, which also contains a highly active, inexpensive, nickel-molybdenum catalyst, to create a fully integrated single material that serves as a complete solar-driven water-splitting system.

    A critical component that contributes to the efficiency and safety of the new system is the special plastic membrane that separates the gases and prevents the possibility of an explosion, while still allowing the ions to flow seamlessly to complete the electrical circuit in the cell. All of the components are stable under the same conditions and work together to produce a high-performance, fully integrated system. The demonstration system is approximately one square centimeter in area, converts 10 percent of the energy in sunlight into stored energy in the chemical fuel, and can operate for more than 40 hours continuously.

    “This new system shatters all of the combined safety, performance, and stability records for artificial leaf technology by factors of 5 to 10 or more ,” Lewis says.

    “Our work shows that it is indeed possible to produce fuels from sunlight safely and efficiently in an integrated system with inexpensive components,” Lewis adds, “Of course, we still have work to do to extend the lifetime of the system and to develop methods for cost-effectively manufacturing full systems, both of which are in progress.”

    Because the work assembled various components that were developed by multiple teams within JCAP, coauthor Chengxiang Xiang, who is co-leader of the JCAP prototyping and scale-up project, says that the successful end result was a collaborative effort. “JCAP’s research and development in device design, simulation, and materials discovery and integration all funneled into the demonstration of this new device,” Xiang says.

    These results are published in a paper titled A monolithically integrated, intrinsically safe, 10% efficient, solar-driven water-splitting system based on active, stable earth-abundant electrocatalysts in conjunction with tandem III-V light absorbers protected by amorphous TiO2 films. In addition to Lewis, Atwater, and Xiang, other Caltech coauthors include graduate student Erik Verlage, postdoctoral scholars Shu Hu and Ke Sun, material processing and integration research engineer Rui Liu, and JCAP mechanical engineer Ryan Jones. Funding was provided by the Office of Science at the U.S. Department of Energy, and the Gordon and Betty Moore Foundation.

    See the full article here.

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    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”
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  • richardmitnick 7:19 am on August 25, 2015 Permalink | Reply
    Tags: , Artificial photosynthesis,   

    From LBL: “News Center Major Advance in Artificial Photosynthesis Poses Win/Win for the Environment” 

    Berkeley Logo

    Berkeley Lab

    April 16, 2015
    Lynn Yarris (510) 486-5375

    Berkeley Lab Researchers Perform Solar-powered Green Chemistry with Captured CO2

    1
    A major advance in artificial photosynthesis poses win/win for the environment – using sequestered CO2 for green chemistry, including renewable fuel production. (Photo by Caitlin Givens)

    A potentially game-changing breakthrough in artificial photosynthesis has been achieved with the development of a system that can capture carbon dioxide emissions before they are vented into the atmosphere and then, powered by solar energy, convert that carbon dioxide into valuable chemical products, including biodegradable plastics, pharmaceutical drugs and even liquid fuels.

    Scientists with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have created a hybrid system of semiconducting nanowires and bacteria that mimics the natural photosynthetic process by which plants use the energy in sunlight to synthesize carbohydrates from carbon dioxide and water. However, this new artificial photosynthetic system synthesizes the combination of carbon dioxide and water into acetate, the most common building block today for biosynthesis.

    “We believe our system is a revolutionary leap forward in the field of artificial photosynthesis,” says Peidong Yang, a chemist with Berkeley Lab’s Materials Sciences Division and one of the leaders of this study. “Our system has the potential to fundamentally change the chemical and oil industry in that we can produce chemicals and fuels in a totally renewable way, rather than extracting them from deep below the ground.”

    2
    This break-through artificial photosynthesis system has four general components: (1) harvesting solar energy, (2) generating reducing equivalents, (3) reducing CO2 to biosynthetic intermediates, and (4) producing value-added chemicals. No image credit.

    Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoSciences Institute (Kavli-ENSI) at Berkeley, is one of three corresponding authors of a paper describing this research in the journal Nano Letters. The paper is titled Nanowire-bacteria hybrids for unassisted solar carbon dioxide fixation to value-added chemicals. The other corresponding authors and leaders of this research are chemists Christopher Chang and Michelle Chang. Both also hold joint appointments with Berkeley Lab and UC Berkeley. In addition, Chris Chang is a Howard Hughes Medical Institute (HHMI) investigator. (See below for a full list of the paper’s authors.)

    The more carbon dioxide that is released into the atmosphere the warmer the atmosphere becomes. Atmospheric carbon dioxide is now at its highest level in at least three million years, primarily as a result of the burning of fossil fuels. Yet fossil fuels, especially coal, will remain a significant source of energy to meet human needs for the foreseeable future. Technologies for sequestering carbon before it escapes into the atmosphere are being pursued but all require the captured carbon to be stored, a requirement that comes with its own environmental challenges.

    3
    (From left) Peidong Yang, Christopher Chang and Michelle Chang led the development of an artificial photosynthesis system that can convert CO2 into valuable chemical products using only water and sunlight. (Photo by Roy Kaltschmidt)

    The artificial photosynthetic technique developed by the Berkeley researchers solves the storage problem by putting the captured carbon dioxide to good use.

    “In natural photosynthesis, leaves harvest solar energy and carbon dioxide is reduced and combined with water for the synthesis of molecular products that form biomass,” says Chris Chang, an expert in catalysts for carbon-neutral energy conversions. “In our system, nanowires harvest solar energy and deliver electrons to bacteria, where carbon dioxide is reduced and combined with water for the synthesis of a variety of targeted, value-added chemical products.”

    By combining biocompatible light-capturing nanowire arrays with select bacterial populations, the new artificial photosynthesis system offers a win/win situation for the environment: solar-powered green chemistry using sequestered carbon dioxide.

    “Our system represents an emerging alliance between the fields of materials sciences and biology, where opportunities to make new functional devices can mix and match components of each discipline,” says Michelle Chang, an expert in biosynthesis. “For example, the morphology of the nanowire array protects the bacteria like Easter eggs buried in tall grass so that these usually-oxygen sensitive organisms can survive in environmental carbon-dioxide sources such as flue gases.”

    The system starts with an “artificial forest” of nanowire heterostructures, consisting of silicon and titanium oxide nanowires, developed earlier by Yang and his research group.

    “Our artificial forest is similar to the chloroplasts in green plants,” Yang says. “When sunlight is absorbed, photo-excited electron−hole pairs are generated in the silicon and titanium oxide nanowires, which absorb different regions of the solar spectrum. The photo-generated electrons in the silicon will be passed onto bacteria for the CO2 reduction while the photo-generated holes in the titanium oxide split water molecules to make oxygen.”

    4
    Cross-sectional SEM image of the nanowire/bacteria hybrid array used in a revolutionary new artificial photosynthesis system. No image credit

    Once the forest of nanowire arrays is established, it is populated with microbial populations that produce enzymes known to selectively catalyze the reduction of carbon dioxide. For this study, the Berkeley team used Sporomusa ovata, an anaerobic bacterium that readily accepts electrons directly from the surrounding environment and uses them to reduce carbon dioxide.

    “S. ovata is a great carbon dioxide catalyst as it makes acetate, a versatile chemical intermediate that can be used to manufacture a diverse array of useful chemicals,” says Michelle Chang. “We were able to uniformly populate our nanowire array with S. ovata using buffered brackish water with trace vitamins as the only organic component.”

    Once the carbon dioxide has been reduced by S. ovata to acetate (or some other biosynthetic intermediate), genetically engineered E.coli are used to synthesize targeted chemical products. To improve the yields of targeted chemical products, the S. ovata and E.coli were kept separate for this study. In the future, these two activities – catalyzing and synthesizing – could be combined into a single step process.

    A key to the success of their artificial photosynthesis system is the separation of the demanding requirements for light-capture efficiency and catalytic activity that is made possible by the nanowire/bacteria hybrid technology. With this approach, the Berkeley team achieved a solar energy conversion efficiency of up to 0.38-percent for about 200 hours under simulated sunlight, which is about the same as that of a leaf.

    The yields of target chemical molecules produced from the acetate were also encouraging – as high as 26-percent for butanol, a fuel comparable to gasoline, 25-percent for amorphadiene, a precursor to the antimaleria drug artemisinin, and 52-percent for the renewable and biodegradable plastic PHB. Improved performances are anticipated with further refinements of the technology.

    “We are currently working on our second generation system which has a solar-to-chemical conversion efficiency of three-percent,” Yang says. “Once we can reach a conversion efficiency of 10-percent in a cost effective manner, the technology should be commercially viable.”

    In addition to the corresponding authors, other co-authors of the Nano Letters paper describing this research were Chong Liu, Joseph Gallagher, Kelsey Sakimoto and Eva Nichols.

    This research was primarily funded by the DOE Office of Science.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    A U.S. Department of Energy National Laboratory Operated by the University of California

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  • richardmitnick 3:48 pm on April 16, 2015 Permalink | Reply
    Tags: , Artificial photosynthesis, ,   

    From LBL: “News Center Major Advance in Artificial Photosynthesis Poses Win/Win for the Environment” 

    Berkeley Logo

    Berkeley Lab

    April 16, 2015
    Lynn Yarris (510) 486-5375

    1
    A major advance in artificial photosynthesis poses win/win for the environment – using sequestered CO2 for green chemistry, including renewable fuel production. (Photo by Caitlin Givens)

    A potentially game-changing breakthrough in artificial photosynthesis has been achieved with the development of a system that can capture carbon dioxide emissions before they are vented into the atmosphere and then, powered by solar energy, convert that carbon dioxide into valuable chemical products, including biodegradable plastics, pharmaceutical drugs and even liquid fuels.

    Scientists with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have created a hybrid system of semiconducting nanowires and bacteria that mimics the natural photosynthetic process by which plants use the energy in sunlight to synthesize carbohydrates from carbon dioxide and water. However, this new artificial photosynthetic system synthesizes the combination of carbon dioxide and water into acetate, the most common building block today for biosynthesis.

    “We believe our system is a revolutionary leap forward in the field of artificial photosynthesis,” says Peidong Yang, a chemist with Berkeley Lab’s Materials Sciences Division and one of the leaders of this study. “Our system has the potential to fundamentally change the chemical and oil industry in that we can produce chemicals and fuels in a totally renewable way, rather than extracting them from deep below the ground.”

    2
    This break-through artificial photosynthesis system has four general components: (1) harvesting solar energy, (2) generating reducing equivalents, (3) reducing CO2 to biosynthetic intermediates, and (4) producing value-added chemicals.

    Yang, who also holds appointments with UC Berkeley and the Kavli Energy NanoSciences Institute (Kavli-ENSI) at Berkeley, is one of three corresponding authors of a paper describing this research in the journal Nano Letters. The paper is titled Nanowire-bacteria hybrids for unassisted solar carbon dioxide fixation to value-added chemicals. The other corresponding authors and leaders of this research are chemists Christopher Chang and Michelle Chang. Both also hold joint appointments with Berkeley Lab and UC Berkeley. In addition, Chris Chang is a Howard Hughes Medical Institute (HHMI) investigator. (See below for a full list of the paper’s authors.)

    The more carbon dioxide that is released into the atmosphere the warmer the atmosphere becomes. Atmospheric carbon dioxide is now at its highest level in at least three million years, primarily as a result of the burning of fossil fuels. Yet fossil fuels, especially coal, will remain a significant source of energy to meet human needs for the foreseeable future. Technologies for sequestering carbon before it escapes into the atmosphere are being pursued but all require the captured carbon to be stored, a requirement that comes with its own environmental challenges.

    3
    (From left) Peidong Yang, Christopher Chang and Michelle Chang led the development of an artificial photosynthesis system that can convert CO2 into valuable chemical products using only water and sunlight. (Photo by Roy Kaltschmidt)

    The artificial photosynthetic technique developed by the Berkeley researchers solves the storage problem by putting the captured carbon dioxide to good use.

    “In natural photosynthesis, leaves harvest solar energy and carbon dioxide is reduced and combined with water for the synthesis of molecular products that form biomass,” says Chris Chang, an expert in catalysts for carbon-neutral energy conversions. “In our system, nanowires harvest solar energy and deliver electrons to bacteria, where carbon dioxide is reduced and combined with water for the synthesis of a variety of targeted, value-added chemical products.”

    By combining biocompatible light-capturing nanowire arrays with select bacterial populations, the new artificial photosynthesis system offers a win/win situation for the environment: solar-powered green chemistry using sequestered carbon dioxide.

    “Our system represents an emerging alliance between the fields of materials sciences and biology, where opportunities to make new functional devices can mix and match components of each discipline,” says Michelle Chang, an expert in biosynthesis. “For example, the morphology of the nanowire array protects the bacteria like Easter eggs buried in tall grass so that these usually-oxygen sensitive organisms can survive in environmental carbon-dioxide sources such as flue gases.”

    The system starts with an “artificial forest” of nanowire heterostructures, consisting of silicon and titanium oxide nanowires, developed earlier by Yang and his research group.

    “Our artificial forest is similar to the chloroplasts in green plants,” Yang says. “When sunlight is absorbed, photo-excited electron−hole pairs are generated in the silicon and titanium oxide nanowires, which absorb different regions of the solar spectrum. The photo-generated electrons in the silicon will be passed onto bacteria for the CO2 reduction while the photo-generated holes in the titanium oxide split water molecules to make oxygen.”

    3
    Cross-sectional SEM image of the nanowire/bacteria hybrid array used in a revolutionary new artificial photosynthesis system.

    Once the forest of nanowire arrays is established, it is populated with microbial populations that produce enzymes known to selectively catalyze the reduction of carbon dioxide. For this study, the Berkeley team used Sporomusa ovata, an anaerobic bacterium that readily accepts electrons directly from the surrounding environment and uses them to reduce carbon dioxide.

    “S. ovata is a great carbon dioxide catalyst as it makes acetate, a versatile chemical intermediate that can be used to manufacture a diverse array of useful chemicals,” says Michelle Chang. “We were able to uniformly populate our nanowire array with S. ovata using buffered brackish water with trace vitamins as the only organic component.”

    Once the carbon dioxide has been reduced by S. ovata to acetate (or some other biosynthetic intermediate), genetically engineered E.coli are used to synthesize targeted chemical products. To improve the yields of targeted chemical products, the S. ovata and E.coli were kept separate for this study. In the future, these two activities – catalyzing and synthesizing – could be combined into a single step process.

    A key to the success of their artificial photosynthesis system is the separation of the demanding requirements for light-capture efficiency and catalytic activity that is made possible by the nanowire/bacteria hybrid technology. With this approach, the Berkeley team achieved a solar energy conversion efficiency of up to 0.38-percent for about 200 hours under simulated sunlight, which is about the same as that of a leaf.

    The yields of target chemical molecules produced from the acetate were also encouraging – as high as 26-percent for butanol, a fuel comparable to gasoline, 25-percent for amorphadiene, a precursor to the antimaleria drug artemisinin, and 52-percent for the renewable and biodegradable plastic PHB. Improved performances are anticipated with further refinements of the technology.

    “We are currently working on our second generation system which has a solar-to-chemical conversion efficiency of three-percent,” Yang says. “Once we can reach a conversion efficiency of 10-percent in a cost effective manner, the technology should be commercially viable.”

    In addition to the corresponding authors, other co-authors of the Nano Letters paper describing this research were Chong Liu, Joseph Gallagher, Kelsey Sakimoto and Eva Nichols.

    This research was primarily funded by the DOE Office of Science.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    A U.S. Department of Energy National Laboratory Operated by the University of California

    University of California Seal

    DOE Seal

     
  • richardmitnick 3:52 pm on March 9, 2015 Permalink | Reply
    Tags: , Artificial photosynthesis, , ,   

    From Caltech: “One Step Closer to Artificial Photosynthesis and “Solar Fuels” 

    Caltech Logo
    Caltech

    03/09/2015
    Ker Than

    1
    Ke Sun, a Caltech postdoc in the lab of George L. Argyros Professor and Professor of Chemistry Nate Lewis, peers into a sample of a new, protective film that he has helped develop to aid in the process of harnessing sunlight to generate fuels.
    Credit: Lance Hayashida/Caltech Marcomm

    Caltech scientists, inspired by a chemical process found in leaves, have developed an electrically conductive film that could help pave the way for devices capable of harnessing sunlight to split water into hydrogen fuel.

    When applied to semiconducting materials such as silicon, the nickel oxide film prevents rust buildup and facilitates an important chemical process in the solar-driven production of fuels such as methane or hydrogen.

    “We have developed a new type of protective coating that enables a key process in the solar-driven production of fuels to be performed with record efficiency, stability, and effectiveness, and in a system that is intrinsically safe and does not produce explosive mixtures of hydrogen and oxygen,” says Nate Lewis, the George L. Argyros Professor and professor of chemistry at Caltech and a coauthor of a new study, published the week of March 9 in the online issue of the journal the Proceedings of the National Academy of Sciences, that describes the film.

    The development could help lead to safe, efficient artificial photosynthetic systems—also called solar-fuel generators or “artificial leaves”—that replicate the natural process of photosynthesis that plants use to convert sunlight, water, and carbon dioxide into oxygen and fuel in the form of carbohydrates, or sugars.

    The artificial leaf that Lewis’ team is developing in part at Caltech’s Joint Center for Artificial Photosynthesis (JCAP) consists of three main components: two electrodes—a photoanode and a photocathode—and a membrane. The photoanode uses sunlight to oxidize water molecules to generate oxygen gas, protons, and electrons, while the photocathode recombines the protons and electrons to form hydrogen gas. The membrane, which is typically made of plastic, keeps the two gases separate in order to eliminate any possibility of an explosion, and lets the gas be collected under pressure to safely push it into a pipeline.

    Scientists have tried building the electrodes out of common semiconductors such as silicon or gallium arsenide—which absorb light and are also used in solar panels—but a major problem is that these materials develop an oxide layer (that is, rust) when exposed to water.

    Lewis and other scientists have experimented with creating protective coatings for the electrodes, but all previous attempts have failed for various reasons. “You want the coating to be many things: chemically compatible with the semiconductor it’s trying to protect, impermeable to water, electrically conductive, highly transparent to incoming light, and highly catalytic for the reaction to make oxygen and fuels,” says Lewis, who is also JCAP’s scientific director. “Creating a protective layer that displayed any one of these attributes would be a significant leap forward, but what we’ve now discovered is a material that can do all of these things at once.”

    The team has shown that its nickel oxide film is compatible with many different kinds of semiconductor materials, including silicon, indium phosphide, and cadmium telluride. When applied to photoanodes, the nickel oxide film far exceeded the performance of other similar films—including one that Lewis’s group created just last year. That film was more complicated—it consisted of two layers versus one and used as its main ingredient titanium dioxide (TiO2, also known as titania), a naturally occurring compound that is also used to make sunscreens, toothpastes, and white paint.

    “After watching the photoanodes run at record performance without any noticeable degradation for 24 hours, and then 100 hours, and then 500 hours, I knew we had done what scientists had failed to do before,” says Ke Sun, a postdoc in Lewis’s lab and the first author of the new study.

    Lewis’s team developed a technique for creating the nickel oxide film that involves smashing atoms of argon into a pellet of nickel atoms at high speeds, in an oxygen-rich environment. “The nickel fragments that sputter off of the pellet react with the oxygen atoms to produce an oxidized form of nickel that gets deposited onto the semiconductor,” Lewis says.

    Crucially, the team’s nickel oxide film works well in conjunction with the membrane that separates the photoanode from the photocathode and staggers the production of hydrogen and oxygen gases.

    “Without a membrane, the photoanode and photocathode are close enough to each other to conduct electricity, and if you also have bubbles of highly reactive hydrogen and oxygen gases being produced in the same place at the same time, that is a recipe for disaster,” Lewis says. “With our film, you can build a safe device that will not explode, and that lasts and is efficient, all at once.”

    Lewis cautions that scientists are still a long way off from developing a commercial product that can convert sunlight into fuel. Other components of the system, such as the photocathode, will also need to be perfected.

    “Our team is also working on a photocathode,” Lewis says. “What we have to do is combine both of these elements together and show that the entire system works. That will not be easy, but we now have one of the missing key pieces that has eluded the field for the past half-century.”

    Along with Lewis and Sun, additional authors on the paper, “Stable solar-driven oxidation of water by semiconducting photoanodes protected by transparent catalytic nickel oxide films,” include Caltech graduate students Fadl Saadi, Michael Lichterman, Xinghao Zhou, Noah Plymale, and Stefan Omelchenko; William Hale, from the University of Southampton; Hsin-Ping Wang and Jr-Hau He, from King Abdullah University in Saudi Arabia; Kimberly Papadantonakis, a scientific research manager at Caltech; and Bruce Brunschwig, the director of the Molecular Materials Research Center at Caltech. Funding was provided by the Office of Science at the U.S. Department of Energy, the National Science Foundation, the Beckman Institute, and the Gordon and Betty Moore Foundation.

    See the full article here.

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    The California Institute of Technology (commonly referred to as Caltech) is a private research university located in Pasadena, California, United States. Caltech has six academic divisions with strong emphases on science and engineering. Its 124-acre (50 ha) primary campus is located approximately 11 mi (18 km) northeast of downtown Los Angeles. “The mission of the California Institute of Technology is to expand human knowledge and benefit society through research integrated with education. We investigate the most challenging, fundamental problems in science and technology in a singularly collegial, interdisciplinary atmosphere, while educating outstanding students to become creative members of society.”
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  • richardmitnick 4:49 pm on March 4, 2014 Permalink | Reply
    Tags: , Artificial photosynthesis, ,   

    From Berkeley Lab: “… Berkeley Lab Researchers Identify Key Intermediate Steps in Artificial Photosynthesis Reaction” 


    Berkeley Lab

    March 03, 2014
    Lynn Yarris (510) 486-5375 lcyarris@lbl.gov

    Artificial photosynthesis, in which we emulate the process used by nature to capture energy from the sun and convert it into electrochemical energy, is expected to be a major asset in any sustainable energy portfolio for the future. Artificial photosynthesis offers the promise of producing liquid fuels that are renewable and can be used without exacerbating global climate change. A key to realizing commercial-scale artificial photosynthesis technology is the development of electrocatalysts that can efficiently and economically carry out water oxidation reaction that is critical to the process. Heinz Frei, a chemist with Berkeley Lab’s Physical Biosciences Division, has been at the forefront of this research effort. His latest results represent an important step forward.

    tube
    Nano-sized crystals of cobalt oxide, an Earth-abundant catalyst, have been shown to be able to effectively carry out the critical photosynthetic reaction of splitting water molecules. (Photo by Roy Kaltschmidt)

    “The oxidation of water to molecular oxygen is a four-electron process involving multiple steps,” Frei says. “We’ve obtained the first direct, temporally resolved observation of two intermediate steps in water oxidation using an Earth-abundant solid catalyst, cobalt oxide, that allowed us to identify the kinetic bottlenecks. With this knowledge, we can devise and design improvements on the cobalt oxide catalyst and its support environment to partially or completely remove these bottlenecks and improve the efficiency of water oxidation.”

    two
    Berkeley Lab’s Heinz Frei and Miao Zhang obtained the first direct temporally resolved observations of intermediate steps in water oxidation using the Earth-abundant catalyst cobalt oxide. (Photo by Roy Kaltschmidt)

    In an artificial photosynthetic system, the oxidation of water molecules into oxygen, electrons and protons (hydrogen ions) provides the electrons needed to produce liquid fuels from carbon dioxide and water. This requires a catalyst that is both efficient in its use of solar photons and fast enough to keep up with solar flux in order to avoid wasting those photons. It should also be robust and affordable on a large-scale. Five years ago, a study led by Frei identified cobalt oxide in the form of single crystal nanoparticles as an excellent candidate for meeting the challenge. However, realizing the full catalytic potential of cobalt oxide nanocrystals requires a better understanding of the individual events in the four-electron cycle of water oxidation.

    To provide this understanding, Frei, working with Miao Zhang and Moreno de Respinis, used a spectroscopic technique known as rapid-scan Fourier transform infrared (FTIR) spectroscopy.

    “Prior to our study, it was not known whether the catalysis, which takes place on the surface of the cobalt oxide crystallites, happens at every cobalt center on the surface at the same speed, or whether a subset of cobalt sites does most of the work while other subsets are slow or merely spectators, Frei says. “Our results show that there is a subset of fast sites where a considerable fraction of the catalysis takes place, and a subset of sites where the catalysis proceeds considerably more slowly. This discovery of these fast and slow sites and the proposed structural difference between two provides the basis for designing cobalt oxide surfaces with higher concentrations of fast sites.”

    Frei, Zhang and de Respinis have reported their findings in the journal Nature Chemistry in a paper titled Time-resolved observations of water oxidation intermediates on a cobalt oxide nanoparticle catalyst.

    This research was supported by the U.S. Department of Energy’s Office of Science.

    See the full article here.

    A U.S. Department of Energy National Laboratory Operated by the University of California

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