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  • richardmitnick 1:50 pm on November 7, 2018 Permalink | Reply
    Tags: , Catalysis, , , , , , Researchers create most complete high-res atomic movie of photosynthesis to date, , ,   

    From SLAC National Accelerator Lab: “Researchers create most complete high-res atomic movie of photosynthesis to date” 

    From SLAC National Accelerator Lab

    November 7, 2018

    Andrew Gordon
    agordon@slac.stanford.edu
    (650) 926-2282

    In a major step forward, SLAC’s X-ray laser captures all four stable states of the process that produces the oxygen we breathe, as well as fleeting steps in between. The work opens doors to understanding the past and creating a greener future.

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    Using SLAC’s X-ray laser, researchers have captured the most complete high-res atomic movie to date of Photosystem II, a key protein complex in plants, algae and cyanobacteria responsible for splitting water and producing the oxygen we breathe. (Gregory Stewart, SLAC National Accelerator Laboratory)

    Despite its role in shaping life as we know it, many aspects of photosynthesis remain a mystery. An international collaboration between scientists at SLAC National Accelerator Laboratory, Lawrence Berkeley National Laboratory and several other institutions is working to change that. The researchers used SLAC’s Linac Coherent Light Source (LCLS) X-ray laser to capture the most complete and highest-resolution picture to date of Photosystem II, a key protein complex in plants, algae and cyanobacteria responsible for splitting water and producing the oxygen we breathe. The results were published in Nature today.

    SLAC/LCLS

    Explosion of life

    When Earth formed about 4.5 billion years ago, the planet’s landscape was almost nothing like what it is today. Junko Yano, one of the authors of the study and a senior scientist at Berkeley Lab, describes it as “hellish.” Meteors sizzled through a carbon dioxide-rich atmosphere and volcanoes flooded the surface with magmatic seas.

    Over the next 2.5 billion years, water vapor accumulating in the air started to rain down and form oceans where the very first life appeared in the form of single-celled organisms. But it wasn’t until one of those specks of life mutated and developed the ability to harness light from the sun and turn it into energy, releasing oxygen molecules from water in the process, that Earth started to evolve into the planet it is today. This process, oxygenic photosynthesis, is considered one of nature’s crown jewels and has remained relatively unchanged in the more than 2 billion years since it emerged.

    “This one reaction made us as we are, as the world. Molecule by molecule, the planet was slowly enriched until, about 540 million years ago, it exploded with life,” said co-author Uwe Bergmann, a distinguished staff scientist at SLAC. “When it comes to questions about where we come from, this is one of the biggest.”

    A greener future

    Photosystem II is the workhorse responsible for using sunlight to break water down into its atomic components, unlocking hydrogen and oxygen. Until recently, it had only been possible to measure pieces of this process at extremely low temperatures. In a previous paper, the researchers used a new method to observe two steps of this water-splitting cycle [Nature]at the temperature at which it occurs in nature.

    Now the team has imaged all four intermediate states of the process at natural temperature and the finest level of detail yet. They also captured, for the first time, transitional moments between two of the states, giving them a sequence of six images of the process.

    The goal of the project, said co-author Jan Kern, a scientist at Berkeley Lab, is to piece together an atomic movie using many frames from the entire process, including the elusive transient state at the end that bonds oxygen atoms from two water molecules to produce oxygen molecules.

    “Studying this system gives us an opportunity to see how metals and proteins work together and how light controls such kinds of reactions,” said Vittal Yachandra, one of the authors of the study and a senior scientist at Berkeley Lab who has been working on Photosystem II for more than 35 years. “In addition to opening a window on the past, a better understanding of Photosystem II could unlock the door to a greener future, providing us with inspiration for artificial photosynthetic systems that produce clean and renewable energy from sunlight and water.”

    Sample assembly line

    For their experiments, the researchers grow what Kern described as a “thick green slush” of cyanobacteria — the very same ancient organisms that first developed the ability to photosynthesize — in a large vat that is constantly illuminated. They then harvest the cells for their samples.

    At LCLS, the samples are zapped with ultrafast pulses of X-rays [Science] to collect both X-ray crystallography and spectroscopy data to map how electrons flow in the oxygen-evolving complex of photosystem II. In crystallography, researchers use the way a crystal sample scatters X-rays to map its structure; in spectroscopy, they excite the atoms in a material to uncover information about its chemistry. This approach, combined with a new assembly-line sample transportation system [Nature Methods], allowed the researchers to narrow down the proposed mechanisms put forward by the research community over the years.

    Mapping the process

    Previously, the researchers were able to determine the room-temperature structure of two of the states at a resolution of 2.25 angstroms; one angstrom is about the diameter of a hydrogen atom. This allowed them to see the position of the heavy metal atoms, but left some questions about the exact positions of the lighter atoms, like oxygen. In this paper, they were able to improve the resolution even further, to 2 angstroms, which enabled them to start seeing the position of lighter atoms more clearly, as well as draw a more detailed map of the chemical structure of the metal catalytic center in the complex where water is split.

    This center, called the oxygen-evolving complex, is a cluster of four manganese atoms and one calcium atom bridged with oxygen atoms. It cycles through the four stable oxidation states, S0-S3, when exposed to sunlight. On a baseball field, S0 would be the start of the game when a player on home base is ready to go to bat. S1-S3 would be players on first, second, and third. Every time a batter connects with a ball, or the complex absorbs a photon of sunlight, the player on the field advances one base. When the fourth ball is hit, the player slides into home, scoring a run or, in the case of Photosystem II, releasing breathable oxygen.

    The researchers were able to snap action shots of how the structure of the complex transformed at every base, which would not have been possible without their technique. A second set of data allowed them to map the exact position of the system in each image, confirming that they had in fact imaged the states they were aiming for.

    1
    In photosystem II, the water-splitting center cycles through four stable states, S0-S3. On a baseball field, S0 would be the start of the game when a batter on home base is ready to hit. S1-S3 would be players waiting on first, second, and third. The center gets bumped up to the next state every time it absorbs a photon of sunlight, just like how a player on the field advances one base every time a batter connects with a ball. When the fourth ball is hit, the player slides into home, scoring a run or, in the case of Photosystem II, releasing the oxygen we breathe. (Gregory Stewart/SLAC National Accelerator Laboratory)

    Sliding into home

    But there are many other things going on throughout this process, as well as moments between states when the player is making a break for the next base, that are a bit harder to catch. One of the most significant aspects of this paper, Yano said, is that they were able to image two moments in between S2 and S3. In upcoming experiments, the researchers hope to use the same technique to image more of these in-between states, including the mad dash for home — the transient state, or S4, where two atoms of oxygen bond together — providing information about the chemistry of the reaction that is vital to mimicking this process in artificial systems.

    “The entire cycle takes nearly two milliseconds to complete,” Kern said. “Our dream is to capture 50-microsecond steps throughout the full cycle, each of them with the highest resolution possible, to create this atomic movie of the entire process.”

    Although they still have a way to go, the researchers said that these results provide a path forward, both in unveiling the mysteries of how photosynthesis works and in offering a blueprint for artificial sources of renewable energy.

    “It’s been a learning process,” said SLAC scientist and co-author Roberto Alonso-Mori. “Over the last seven years we’ve worked with our collaborators to reinvent key aspects of our techniques. We’ve been slowly chipping away at this question and these results are a big step forward.”

    In addition to SLAC and Berkeley Lab, the collaboration includes researchers from Umeå University, Uppsala University, Humboldt University of Berlin, the University of California, Berkeley, the University of California, San Francisco and the Diamond Light Source.

    Key components of this work were carried out at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL), Berkeley Lab’s Advanced Light Source (ALS) and Argonne National Laboratory’s Advanced Photon Source (APS). LCLS, SSRL, APS, and ALS are DOE Office of Science user facilities. This work was supported by the DOE Office of Science and the National Institutes of Health, among other funding agencies.

    SLAC/SSRL

    LBNL/ALS

    ANL APS

    See the full article here .


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    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

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  • richardmitnick 11:39 am on November 7, 2018 Permalink | Reply
    Tags: Acoustic phonons, , Catalysis, , Dancing atoms in perovskite materials provide insight into how solar cells work, , , ,   

    From SLAC National Accelerator Lab: “Dancing atoms in perovskite materials provide insight into how solar cells work” 

    From SLAC National Accelerator Lab

    November 6, 2018
    Ali Sundermier

    1
    When the researchers scattered neutrons off the perovskite material (red beam) they were able to measure the energy the neutrons lost or gained (white and blue lines). Using this information, they were able to see the structure and motion of the atoms and molecules within the material (arrangement of blue and purple spheres). (Greg Stewart/SLAC National Accelerator Laboratory)

    A new study is a step forward in understanding why perovskite materials work so well in energy devices and potentially leads the way toward a theorized “hot” technology that would significantly improve the efficiency of today’s solar cells.

    A closer look at materials that make up conventional solar cells reveals a nearly rigid arrangement of atoms with little movement. But in hybrid perovskites, a promising class of solar cell materials, the arrangements are more flexible and atoms dance wildly around, an effect that impacts the performance of the solar cells but has been difficult to measure.

    In a paper published in the PNAS, an international team of researchers led by the U.S. Department of Energy’s SLAC National Accelerator Laboratory has developed a new understanding of those wild dances and how they affect the functioning of perovskite materials. The results could explain why perovskite solar cells are so efficient and aid the quest to design hot-carrier solar cells, a theorized technology that would almost double the efficiency limits of conventional solar cells by converting more sunlight into usable electrical energy.

    Piece of the puzzle

    Perovskite solar cells, which can be produced at room temperature, offer a less expensive and potentially better performing alternative to conventional solar cell materials like silicon, which have to be manufactured at extremely high temperatures to eliminate defects. But a lack of understanding about what makes perovskite materials so efficient at converting sunlight into electricity has been a major hurdle to producing even higher efficiency perovskite solar cells.

    “It’s really only been over the last five or six years that people have developed this intense interest in solar perovskite materials,” says Mike Toney, a distinguished staff scientist at SLAC’s Stanford Synchrotron Radiation Light Source (SSRL) who led the study.

    SLAC/SSRL

    “As a consequence, a lot of the foundational knowledge about what makes the materials work is missing. In this research, we provided an important piece of this puzzle by showing what sets them apart from more conventional solar cell materials. This provides us with scientific underpinnings that will allow us to start engineering these materials in a rational way.”

    Keeping it hot

    When sunlight hits a solar cell, some of the energy can be used to kick electrons in the material up to higher energy states. These higher-energy electrons are funneled out of the material, producing electricity.

    But before this happens, a majority of the sun’s energy is lost to heat with some fraction also lost during the extraction of usable energy or due to inefficient light collection. In many conventional solar cells, such as those made with silicon, acoustic phonons – a sort of sound wave that propagates through material – are the primary way that this heat is carried through the material. The energy lost by the electron as heat limits the efficiency of the solar cell.

    In this study, theorists from the United Kingdom, led by Imperial College Professor Aron Walsh and electronic structure theorists Jonathan Skelton and Jarvist Frost, provided a theoretical framework for interpreting the experimental results. They predicted that acoustic phonons traveling through perovskites would have short lifetimes as a result of the flexible arrangements of dancing atoms and molecules in the material.

    Stanford chemists Hema Karunadasa and Ian Smith were able to grow the large, specialized single crystals that were essential for this work. With the help of Peter Gehring, a physicist at the NIST Center for Neutron Research, the team scattered neutrons off these perovskite single crystals in a way that allowed them to retrace the motion of the atoms and molecules within the material. This allowed them to precisely measure the lifetime of the acoustic phonons.

    The research team found that in perovskites, acoustic phonons are incredibly short-lived, surviving for only 10 to 20 trillionths of a second. Without these phonons trucking heat through the material, the electrons might stay hot and hold onto their energy as they’re pulled out of the material. Harnessing this effect could potentially lead to hot-carrier solar cells with efficiencies that are nearly twice as high as conventional solar cells.

    In addition, this phenomenon could explain how perovskite solar cells work so well despite the material being riddled with defects that would trap electrons and dampen performance in other materials.

    “Since phonons in perovskites don’t travel very far, they end up heating the area surrounding the electrons, which might provide the boost the electrons need to escape the traps and continue on their merry way,” Toney says.

    Transforming energy production

    To follow up on this study, researchers at the Center for Hybrid Organic-Inorganic Semiconductors for Energy (CHOISE) Energy Frontier Research Center led by DOE’s National Renewable Energy Laboratory will investigate this phenomenon in more complicated perovskite materials that are shown to be more efficient in energy devices. They would like to figure out how changing the chemical make-up of the material affects acoustic phonon lifetimes.

    “We need to fundamentally transform our energy system as quickly as possible,” says Aryeh Gold-Parker, who co-led the study as a PhD student at Stanford University and SLAC. “As we move toward a low-carbon future, a very important piece is having cheap and efficient solar cells. The hope in perovskites is that they’ll lead to commercial solar panels that are more efficient and cheaper than the ones on the market today.”

    The research team also included scientists from NIST; the University of Bath and Kings College London, both in the UK; and Yonsei University in Korea.

    SSRL is a DOE Office of Science user facility. This work was supported by the DOE’s Office of Science and the Solar Energy Technologies Office; the Engineering and Physical Sciences Research Council; the Royal Society; and the Leverhulme Trust.

    See the full article here .


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    Please help promote STEM in your local schools.

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    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

     
  • richardmitnick 9:34 am on October 23, 2018 Permalink | Reply
    Tags: , Catalysis, , KAUST,   

    KAUST via Nature Magazine: “The holistic approach to catalyzing change” 

    1

    KAUST

    via

    Nature Mag
    Nature Magazine

    Rethinking industry-scale catalytic processes could slash global energy consumption and even turn carbon dioxide into a valuable commodity.

    Sep 6, 2018

    2

    Jorge Gascon
    Professor/Center Director

    Chemical catalysts don’t spring to mind as revolutionary materials, yet Jorge Gascon, director of the KAUST Catalysis Center, says catalysts have sparked some of the biggest revolutions in human history. Take the Haber Bosch process, for example. This first practical method for industrial synthetic fertilizer production, developed in the early 1900s, triggered the agricultural revolution that fuels farming today.

    Catalysis research is poised to change the world again, Gascon claims. “We are about to have another revolution in the way we use our resources and in the way we produce and store energy, and I believe catalysis will play a huge role,” he says. “We at KAUST are in an excellent position to contribute strongly to that transition.”

    Gascon’s research—and that of the Center he has led since joining KAUST in October 2017—revolves around sustainability. “The main purpose of my group is to develop and deploy sustainable technologies for the production of chemicals, energy carriers and new environmental applications. Process intensification, feedstock efficiency and reduction of energy usage are our main objectives.”

    For example, the team recently gained insights that could significantly enhance the performance of catalysts that convert methanol into major chemical feedstocks called olefins1,2. These high-demand chemicals are traditionally sourced from oil, but new catalysts—which Gascon’s work is helping to make more efficient—enable olefin production from coal and natural gas, alleviating a bottleneck in olefin supply.

    Another major area of focus in Gascon’s lab, as well as others labs in the Center, is to develop catalysts that can efficiently turn carbon dioxide into a valuable chemical feedstock. The team has developed several catalysts that can combine CO2 with hydrogen, converting the troublesome greenhouse gas into a range of useful small hydrocarbon molecules.

    At the moment, the hydrogen for the process comes from natural gas in such a way that it generates CO2. “If the situation changes and we start to use solar energy to produce hydrogen from water, then that hydrogen can be used to make very useful products out of carbon dioxide,” Gascon says. Should governments introduce a tax on carbon dioxide emissions, recycling CO2 would become even more favorable. “Our main target is to make those technologies as efficient as possible so it becomes attractive to valorize carbon dioxide.”

    The catalysts Gascon works with are typically porous crystalline solids, such as zeolites and metal-organic frameworks. “I like these materials because working with crystalline structures gives you much more control over design,” Gascon says. The structures of these materials can be tuned at the nanoscale. By making such changes and noting the effects on catalytic performance, it is possible to gain deep insights into how the catalysts function and thus they can be improved. “Being able to explain a thing you can measure at the macroscale, by the structures that you build at the nanoscale, is super nice,” Gascon says.

    The great strength of the Catalysis Center is that there are researchers focused on every aspect of catalytic reaction development and implementation, Gascon adds. “We design new active sites at the nanoscale, but we also design how the catalyst particles should look, and now we are starting to design how reactors should look,” Gascon says. “We are starting to have a holistic approach. I think the Catalysis Center is probably unique in that we are able to cover almost every relevant aspect in catalysis.”

    One of the Center’s flagship projects, which began its second phase in early 2018, is the one-step conversion of crude oil to chemicals. The project illustrates the power of the holistic approach. Today, refineries pass crude oil through cleaning steps, then separate the oil into various chemical fractions, before those fractions are catalytically processed to form chemical feedstocks and fuels. “We want to avoid all those initial steps and go directly to the processing part,” says Gascon. Cutting these steps could save a lot of energy.

    To directly make chemicals from crude oil, you need catalysts that are very robust and resistant to poisoning by contaminants in the oil. But for the process to be successful, the team needs to go far beyond the catalyst itself. “You need to think of different reactor concepts to the ones that are used at the moment,” Gascon says. “You need to redesign the whole process. This is the type of research where I believe our Center can make a difference.”

    The project is a revolutionary idea in the best tradition of catalysis research. And the unique funding structure, facilities and expertise at KAUST make the Catalysis Center the place to do it, says Gascon. “From a research point of view, this is like Disneyland,” he says. “The possibilities here are absolutely amazing. This is probably the only place in the world where you are your own limit.”

    See the full article here .

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    Stem Education Coalition

    Nature is a weekly international journal publishing the finest peer-reviewed research in all fields of science and technology on the basis of its originality, importance, interdisciplinary interest, timeliness, accessibility, elegance and surprising conclusions. Nature also provides rapid, authoritative, insightful and arresting news and interpretation of topical and coming trends affecting science, scientists and the wider public.

     
  • richardmitnick 11:38 am on September 29, 2018 Permalink | Reply
    Tags: Actinide chemistry, , , Catalysis, , Computational chemistry, , , Microsoft Quantum Development Kit, NWChem an open source high-performance computational chemistry tool funded by DOE, , Quantum Information Science   

    From Pacific Northwest National Lab: “PNNL’s capabilities in quantum information sciences get boost from DOE grant and new Microsoft partnership” 

    PNNL BLOC
    From Pacific Northwest National Lab

    September 28, 2018
    Susan Bauer, PNNL,
    susan.bauer@pnnl.gov
    (509) 372-6083

    1
    No image caption or credit

    On Monday, September 24, the U.S. Department of Energy announced $218 million in funding for dozens of research awards in the field of Quantum Information Science. Nearly $2 million was awarded to DOE’s Pacific Northwest National Laboratory for a new quantum computing chemistry project.

    “This award will be used to create novel computational chemistry tools to help solve fundamental problems in catalysis, actinide chemistry, and materials science,” said principal investigator Karol Kowalski. “By collaborating with the quantum computing experts at Lawrence Berkeley National Laboratory, Oak Ridge National Laboratory, and the University of Michigan, we believe we can help reshape the landscape of computational chemistry.”

    Kowalski’s proposal was chosen along with 84 others to further the nation’s research in QIS and lay the foundation for the next generation of computing and information processing as well as an array of other innovative technologies.

    While Kowalski’s work will take place over the next three years, computational chemists everywhere will experience a more immediate upgrade to their capabilities in computational chemistry made possible by a new PNNL-Microsoft partnership.

    “We are working with Microsoft to combine their quantum computing software stack with our expertise on high-performance computing approaches to quantum chemistry,” said Sriram Krishnamoorthy who leads PNNL’s side of this collaboration.

    Microsoft will soon release an update to the Microsoft Quantum Development Kit which will include a new chemical simulation library developed in collaboration with PNNL. The library is used in conjunction with NWChem, an open source, high-performance computational chemistry tool funded by DOE. Together, the chemistry library and NWChem will help enable quantum solutions and allow researchers and developers a higher level of study and discovery.

    “Researchers everywhere will be able to tackle chemistry challenges with an accuracy and at a scale we haven’t experienced before,” said Nathan Baker, director of PNNL’s Advanced Computing, Mathematics, and Data Division. Wendy Shaw, the lab’s division director for physical sciences, agrees with Baker. “Development and applications of quantum computing to catalysis problems has the ability to revolutionize our ability to predict robust catalysts that mimic features of naturally occurring, high-performing catalysts, like nitrogenase,” said Shaw about the application of QIS to her team’s work.

    PNNL’s aggressive focus on quantum information science is driven by a research interest in the capability and by national priorities. In September, the White House published the National Strategic Overview for Quantum Information Science and hosted a summit on the topic. Through their efforts, researchers hope to unleash quantum’s unprecedented processing power and challenge traditional limits for scaling and performance.

    In addition to the new DOE funding, PNNL is also pushing work in quantum conversion through internal investments. Researchers are determining which software architectures allow for efficient use of QIS platforms, designing QIS systems for specific technologies, imagining what scientific problems can best be solved using QIS systems, and identifying materials and properties to build quantum systems. The effort is cross-disciplinary; PNNL scientists from its computing, chemistry, physics, and applied mathematics domains are all collaborating on quantum research and pushing to apply their discoveries. “The idea for this internal investment is that PNNL scientists will take that knowledge to build capabilities impacting catalysis, computational chemistry, materials science, and many other areas,” said Krishnamoorthy.

    Krishnamoorthy wants QIS to be among the priorities that researchers think about applying to all of PNNL’s mission areas. With continued investment from the DOE and partnerships with industry leaders like Microsoft, that just might happen.

    See the full article here .

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    Pacific Northwest National Laboratory (PNNL) is one of the United States Department of Energy National Laboratories, managed by the Department of Energy’s Office of Science. The main campus of the laboratory is in Richland, Washington.

    PNNL scientists conduct basic and applied research and development to strengthen U.S. scientific foundations for fundamental research and innovation; prevent and counter acts of terrorism through applied research in information analysis, cyber security, and the nonproliferation of weapons of mass destruction; increase the U.S. energy capacity and reduce dependence on imported oil; and reduce the effects of human activity on the environment. PNNL has been operated by Battelle Memorial Institute since 1965.

    i1

     
  • richardmitnick 8:21 am on September 8, 2018 Permalink | Reply
    Tags: , , , Catalysis, , , , 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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    Please help promote STEM in your local schools.

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    U Cambridge Campus

    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 2:47 pm on August 31, 2018 Permalink | Reply
    Tags: A Tiny Protein Like This May Have Kick-Started Life On Earth, Ambidoxin, , , , Catalysis, , Computer modeling, Ferredoxins, , Peptides, , Redox catalysis, , Rutgers' Environmental Biophysics and Molecular Ecology Laboratory   

    From Rutgers University via Forbes: “A Tiny Protein Like This May Have Kick-Started Life On Earth” 

    Rutgers smaller
    Our Great Seal.

    From Rutgers University

    via

    Forbes

    Aug 31, 2018
    Fiona McMillan

    1
    Ambidoxin is a synthetic small protein that wraps around a metal core composed of iron and sulfur. Vikas Nanda/Rutgers University-New Brunswick

    Researchers have reverse engineered a simple protein that may have helped kick start life on Earth.

    Their findings, published in the Journal of the American Chemical Society, provide strong new evidence that simple protein catalysts could have contributed to the development of life.

    A few decades ago, a chemist named Günter Wächtershäuser put forward a theory that life most likely began on volcanic rocks in the ocean that were rich in iron, sulfur and a variety of other minerals and elements useful for the kind of chemistry needed for simple life forms to emerge. He and others went on to surmise that this process would have been helped along by peptides — which are short proteins — that would have been capable of functioning as catalysts.

    A catalyst is anything that can speed up or increase the likelihood of a chemical reaction. Protein catalysts, or enzymes, are able to achieve this by bringing the reactants together in close proximity, and sometimes by also bringing other factors into the mix that help the reaction along, such as a metal ion, a water molecule, or some other type of molecule that gets things moving. In this way, enzymes are like really good party hosts.

    Of course, modern enzymes are often big bulky things comprising hundreds of amino acids. There are 20 amino acids to choose from, so countless combinations are possible. These big, complex enzymes are able fold into a stunning variety of elaborate shapes, enabling them to capture and hold reactants, and carry out reactions. They’re absolutely critical to the function of both simple and complex cellular life; we literally couldn’t live without them.

    However, such complex molecules took billions of years to evolve. Wächtershäuser and others have proposed that the earliest peptides would have had much simpler structures — perhaps just 10 or 20 amino acids — with just enough chemical complexity to enable them to carry out basic primordial chemistry.

    Yet exactly what such peptides may have looked like has been a mystery.

    3
    Underwater sulfur chimneys at Northwest Eifuku volcano. Life may have begun on volcanic underwater rocks like these.Credit: Pacific Ring of Fire 2004 Expedition. NOAA Office of Ocean Exploration; Dr. Bob Embley, NOAA PMEL, Chief Scientist; Public domain image

    Now Vikas Nanda and his colleagues at Rutgers University have used computer modeling to find out just how simple a peptide can get while still retaining the ability to function as a catalyst.

    In so doing, they have designed a peptide only 12 amino acids long that is able to wrap around a cluster of iron and sulfur atoms, which closely resemble iron-sulfur clusters that would have been found in ancient oceans.

    Interestingly, the peptide, which they named ambidoxin, doesn’t need the full variety of 20 amino acids available to modern proteins — it only requires two types of amino acid. Given its simplicity, the researchers suggest such a structure could have evolved spontaneously under the right conditions.

    Importantly, ambidoxin is able to carry out simple oxidation-reduction chemistry, also known as redox catalysis. Essentially it is able to be charged and discharged without falling apart, effectively enabling it to shuttle electrons from one place to another.

    “Modern proteins called ferredoxins do this, shuttling electrons around the cell to promote metabolism,” says senior author Paul G. Falkowski, who leads Rutgers’ Environmental Biophysics and Molecular Ecology Laboratory.

    “A primordial peptide like the one we studied may have served a similar function in the origins of life,” he says.

    By shuttling electrons around, ambidoxin (or something like it) may have contributed to early metabolic cycles, and could have served as a precursor to longer, more complex enzymes.

    See the full article here .


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    Rutgers, The State University of New Jersey, is a leading national research university and the state’s preeminent, comprehensive public institution of higher education. Rutgers is dedicated to teaching that meets the highest standards of excellence; to conducting research that breaks new ground; and to providing services, solutions, and clinical care that help individuals and the local, national, and global communities where they live.

    Founded in 1766, Rutgers teaches across the full educational spectrum: preschool to precollege; undergraduate to graduate; postdoctoral fellowships to residencies; and continuing education for professional and personal advancement.

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    • stewarthoughblog 6:08 pm on August 31, 2018 Permalink | Reply

      How to get this straight? Ambidoxin is a synthetic molecule? It took intelligent designers to reverse engineer a simple protein? A totally open system of underwater volcanic rocks supposed was the source for this molecular development? Protein enzymes also had to form to “capture, hold and carry out reactions? the complex molecular enzymes took billions of years to “evolve, when evolution only occurs to living reproductive organisms that did not exist yet? Regardless of this obstacle, the 10-20 amino acids proposed to make its simpler for the formation of the molecule must be homochiral, a condition that no naturalistic process can accomplish. Which “2 amino acids?” Only the simplest can form naturalistically.

      There is no way the full article can rectify the absurd propositions in this article. This is intellectually insulting in its preposterous and nonscientific speculation.

      Like

    • richardmitnick 1:12 pm on September 1, 2018 Permalink | Reply

      • stewarthoughblog 6:42 pm on September 1, 2018 Permalink | Reply

        Thank you for the reply and illumination of astrobiology.net’s beliefs. Nothing in their article answers the questions I posed.

        I can only offer my questions to them for serious response, as the astrobiology profession is motivated to pursue any and all aspects of potential life generation from a naturalistic worldview that is motivated to posit any and all mechanisms for the potential creation, development and sustaining of life. More cynically, their paycheck and funding depends on serious investigation and support of naturalistic processes, regardless of their viability.

        The second to last para of the article reveals an ostensible reliance on “evolution” for the formation of abiotic pre-assemblages of molecules that logically advocate abiogenetic assembly results. This, despite the well established disavowal by evolutionists of any evolution within abiogenesis. The astrobiologists are not so ideologically dogmatic if some origin of life milestone can be attained through evolutionary processes.

        Thank you. Regards.

        Like

  • richardmitnick 6:54 am on August 3, 2018 Permalink | Reply
    Tags: , Catalysis, , How synthetic diamonds grow, ,   

    From SLAC Lab: “In a first, scientists precisely measure how synthetic diamonds grow” 

    From SLAC Lab

    August 2, 2018
    Glennda Chui

    1
    A SLAC-Stanford study has precisely measured for the first time how synthetic diamonds grow from diamondoid seeds, like the one at left. (Greg Stewart, SLAC National Accelerator Laboratory)

    A SLAC-Stanford study reveals exactly what it takes for diamond to crystallize around a “seed” cluster of atoms. The results apply to industrial processes and to what happens in clouds overhead.

    Natural diamond is forged by tremendous pressures and temperatures deep underground. But synthetic diamond can be grown by nucleation, where tiny bits of diamond “seed” the growth of bigger diamond crystals. The same thing happens in clouds, where particles seed the growth of ice crystals that then melt into raindrops.

    Scientists have now observed for the first time how diamonds grow from seed at an atomic level, and discovered just how big the seeds need to be to kick the crystal growing process into overdrive.

    The results, published this week in Proceedings of the National Academy of Sciences, shed light on how nucleation proceeds not just in diamonds, but in the atmosphere, in silicon crystals used for computer chips and even in proteins that clump together in neurological diseases.

    “Nucleation growth is a core tenet of materials science, and there’s a theory and a formula that describes how this happens in every textbook,” says Nicholas Melosh, a professor at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory who led the research. “It’s how we describe going from one material phase to another, for example from liquid water to ice.”

    But interestingly, he says, “despite the widespread use of this process everywhere, the theory behind it had never been tested experimentally, because observing how crystal growth starts from atomic-scale seeds is extremely difficult.”

    2
    An illustration shows how diamondoids (left), the tiniest possible specks of diamond, were used to seed the growth of nanosized diamond crystals (right). Trillions of diamondoids were attached to the surface of a silicon wafer, which was then tipped on end and exposed to a hot plasma (purple) containing carbon and hydrogen, the two elements needed to form diamond. A new study found that diamond growth really took off when seeds contained at least 26 carbon atoms. (Greg Stewart/SLAC National Accelerator Laboratory)

    The smallest possible specks

    In fact, scientists have known for a long time that the current theory often overestimates how much energy it takes to kick off the nucleation process, and by quite a bit. They’ve come up with potential ways to reconcile the theory with reality, but until now those ideas have been tested only at a relatively large scale, for instance with protein molecules, rather than at the atomic scale where nucleation begins.

    To see how it works at the smallest scale, Melosh and his team turned to diamondoids, the tiniest possible bits of diamond. The smallest ones contain just 10 carbon atoms. These specks are the focus of a DOE-funded program at SLAC and Stanford where naturally occurring diamondoids are isolated from petroleum fluids, sorted by size and shape and studied. Recent experiments suggest they could be used as Lego-like blocks for assembling nanowires or “molecular anvils” for triggering chemical reactions, among other things.

    The latest round of experiments was led by Stanford postdoctoral researcher Matthew Gebbie. He’s interested in the chemistry of interfaces – places where one phase of matter encounters another, for instance the boundary between air and water. It turns out that interfaces are incredibly important in growing diamonds with a process called CVD, or chemical vapor deposition, that’s widely used to make synthetic diamond for industry and jewelry.

    “What I’m excited about is understanding how size and shape and molecular structure influence the properties of materials that are important for emerging technologies,” Gebbie says. “That includes nanoscale diamonds for use in sensors and in quantum computing. We need to make them reliably and with consistently high quality.”

    Diamond or pencil lead?

    To grow diamond in the lab with CVD, tiny bits of crushed diamond are seeded onto a surface and exposed to a plasma – a cloud of gas heated to such high temperatures that electrons are stripped away from their atoms. The plasma contains hydrogen and carbon, the two elements needed to form a diamond.

    This plasma can either dissolve the seeds or make them grow, Gebbie says, and the competition between the two determines whether bigger crystals form. Since there are many ways to pack carbon atoms into a solid, it all has to be done under just the right conditions; otherwise you can end up with graphite, commonly known as pencil lead, instead of the sparkly stuff you were after.

    Diamondoid seeds give scientists a much finer level of control over this process. Although they’re too small to see directly, even with the most powerful microscopes, they can be precisely sorted according to the number of carbon atoms they contain and then chemically attached to the surface of a silicon wafer so they’re pinned in place while being exposed to plasma. The crystals that grow around the seeds eventually get big enough to count under a microscope, and that’s what the researchers did.

    The magic number is 26

    Although diamondoids had been used to seed the growth of diamonds before, these were the first experiments to test the effects of using seeds of various sizes. The team discovered that crystal growth really took off with seeds that contain at least 26 carbon atoms.

    Even more important, Gebbie says, they were able to directly measure the energy barrier that diamondoid particles have to overcome in order to grow into crystals.

    “It was thought that this barrier must be like a gigantic mountain that the carbon atoms should not be able to cross – and, in fact, for decades there’s been an open question of why we could even make diamonds in the first place,” he says. “What we found was more like a mild hill.”

    Gebbie adds, “This is really fundamental research, but at the end of the day, what we’re really excited about and driving for is a predictable and reliable way to make diamond nanomaterials. Now that we’ve developed the underlying scientific knowledge needed to do that, we’ll be looking for ways to put these diamond nanomaterials to practical use.”

    This research took place at SIMES, the Stanford Institute for Materials and Energy Sciences, with major funding from the DOE Office of Science. In addition to SLAC and Stanford, researchers contributing to this study came from the Institute of Physics of the Czech Academy of Sciences, University Hasselt in Belgium and the Institute of Organic Chemistry at Justus-Liebig University in Germany.

    See the full article here .


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    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.

     
  • richardmitnick 3:36 pm on December 29, 2017 Permalink | Reply
    Tags: -ray photoelectron and infrared reflection absorption spectroscopy, , , , , Catalysis, , , We are the first team to trap a noble gas in a 2D porous structure at room temperature,   

    From BNL: “Studying Argon Gas Trapped in Two-Dimensional Array of Tiny ‘Cages'” 

    Brookhaven Lab

    July 17, 2017
    Ariana Tantillo
    atantillo@bnl.gov
    (631) 344-2347

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

    Understanding how individual atoms enter and exit the nanoporous frameworks could help scientists design new materials for gas separation and nuclear waste remediation.

    1
    (Left to right) Anibal Boscoboinik, Jian-Qiang Zhong, Dario Stacchiola, Nusnin Akter, Taejin Kim, Deyu Lu, and Mengen Wang at Brookhaven Lab’s Center for Functional Nanomaterials (CFN). The team of scientists (including John Kestell and Alejandro Boscoboinik) carried out experiments at CFN, at Brookhaven’s National Synchrotron Light Source I and II, and in the Lab’s Chemistry Division to study the trapping of individual argon gas atoms (blue prop in Stacchiola’s hand) in two-dimensional (2D) nanoporous frameworks like the one Boscoboinik and Zhong are holding. They had been using these 2D frameworks as analogues to study catalysis in 3D porous materials called zeolites (structural model on the table), which speed up many important reactions such as the conversion of nitrogen-oxide emissions into nitrogen.

    Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory had just finished an experiment with a two-dimensional (2D) structure they synthesized for catalysis research when, to their surprise, they discovered that atoms of argon gas had gotten trapped inside the structure’s nanosized pores. Argon and other noble gases have previously been trapped in three-dimensional (3D) porous materials, but immobilizing them on surfaces had only been achieved by either cooling the gases to very low temperatures to condense them, or by accelerating gas ions to implant them directly into materials.

    “We are the first team to trap a noble gas in a 2D porous structure at room temperature,” said Anibal Boscoboinik, a materials scientist at Brookhaven Lab’s Center for Functional Nanomaterials (CFN), a DOE Office of Science User Facility where part of the research was conducted.

    This achievement, reported in a paper published today in Nature Communications, will enable scientists to use traditional surface-science tools—such as x-ray photoelectron and infrared reflection absorption spectroscopy—to perform detailed studies of single gas atoms in confinement. The knowledge gained from such research could inform the design, selection, and improvement of adsorbent materials and membranes for capturing gases such as radioactive krypton and xenon generated by nuclear power plants.

    The team of scientists from Brookhaven Lab, Stony Brook University, and the National University of San Luis in Argentina synthesized 2D aluminosilicate (composed of aluminum, silicon, and oxygen) films on top of a ruthenium metal surface. The scientists created this 2D model catalyst material to study the chemical processes happening in the industrially used 3D catalyst (called a zeolite), which has a cage-like structure with open pores and channels the size of small molecules. Because the catalytically active surface is enclosed within these cavities, it is difficult to probe with traditional surface-science tools. The 2D analogue material has the same chemical composition and active site as the 3D porous zeolite but its active site is exposed on a flat surface, which is easier to access with such tools.

    2
    An artistic rendering of an argon (Ar) atom trapped in a nanocage that has a silicon (Si)-oxygen (O) framework.

    To confirm that the argon atoms were trapped in these “nanocages,” the scientists exposed the 2D material to argon gas and measured the kinetic energy and number of electrons ejected from the surface after striking it with an x-ray beam. They performed these studies at the former National Synchrotron Light Source I (NSLS-I) and its successor facility, NSLS-II (both DOE Office of Science User Facilities at Brookhaven), with an instrument developed and operated by the CFN.

    BNL NSLS

    BNL NSLS-II

    BNL NSLS II

    Because the binding energies of core electrons are unique to each chemical element, the resulting spectra reveal the presence and concentration of elements on the surface. In a separate experiment conducted at the CFN, they grazed a beam of infrared light over the surface while introducing argon gas. When atoms absorb light of a specific wavelength, they undergo changes in their vibrational motions that are specific to that element’s molecular structure and chemical bonds.

    To get a better understanding of how the framework itself contributes to caging, the scientists investigated the trapping mechanism with silicate films, which are similar in structure to the aluminosilicates but contain no aluminum. In this case, they discovered that not all of the argon gets trapped in the cages—a small amount goes to the interface between the framework and ruthenium surface. This interface is too compressed in the aluminosilicate films for argon to squeeze in.

    After studying adsorption, the scientists examined the reverse process of desorption by incrementally increasing the temperature until the argon atoms completely released from the surface at 350 degrees Fahrenheit. They corroborated their experimental spectra with theoretical calculations of the amount of energy associated with argon entering and leaving the cages.

    In another infrared spectroscopy experiment conducted in Brookhaven’s Chemistry Division, they explored how the presence of argon in the cages affects the passage of carbon monoxide molecules through the framework. They found that argon restricts the number of molecules that adsorb onto the ruthenium surface.

    “In addition to trapping small atoms, the cages could be used as molecular sieves for filtering carbon monoxide and other small molecules, such as hydrogen and oxygen,” said first author Jian-Qiang Zhong, a CFN research associate.

    While their main goal going forward will be to continue investigating zeolite catalytic processes on the 2D material, the scientists are interested in learning the impact of different pore sizes on the materials’ ability to trap and filter gas molecules.

    “As we seek to better understand the material, interesting and unexpected findings keep coming up,” said Boscoboinik. “The ability to use surface-science methods to understand how a single atom of gas behaves when it is confined in a very small space opens up lots of interesting questions for researchers to answer.”

    This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility at Lawrence Berkeley National Laboratory, and was supported by Brookhaven’s Laboratory Directed Research and Development program and the National Scientific and Technical Research Council (CONICET) of Argentina.

    NERSC Cray XC40 Cori II supercomputer

    LBL NERSC Cray XC30 Edison supercomputer


    The Genepool system is a cluster dedicated to the DOE Joint Genome Institute’s computing needs. Denovo is a smaller test system for Genepool that is primarily used by NERSC staff to test new system configurations and software.

    NERSC PDSF


    PDSF is a networked distributed computing cluster designed primarily to meet the detector simulation and data analysis requirements of physics, astrophysics and nuclear science collaborations.

    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 2:16 pm on December 22, 2017 Permalink | Reply
    Tags: , , , Catalysis,   

    From ANL: “A catalytic balancing act “ 

    Argonne Lab
    News from Argonne National Laboratory

    1
    Argonne scientists and their collaborators have used a new and counterintuitive approach to balance three important factors — activity, stability and conductivity — in a new catalyst designed for splitting water. (Image by Argonne National Laboratory.)

    Balance forms the foundation for a happy life or a healthy diet. For scientists working to design new catalysts to create renewable energy, balancing different materials and their properties is equally important. (Catalysts help accelerate chemical reactions.)

    In a new study Nature Communications, researchers from the U.S. Department of Energy’s (DOE) Argonne National Laboratory, Johns Hopkins University, Drexel University and several universities in South Korea used a new and counterintuitive approach to create a better catalyst that supports one of the reactions involved in splitting water into hydrogen and oxygen. Scientists plan to use the generated hydrogen as a clean fuel.

    ______________________________________________________
    “Finding a material that works well for energy conversion or storage is like creating a happy marriage.” – Nenad Markovic, Argonne materials scientist and study author.
    ______________________________________________________

    By first creating an alloy of two of the densest naturally occurring elements and then removing one, the scientists reshaped the remaining material’s structure so that it better balanced three factors important for chemical reactions: activity, stability and conductivity.

    “Finding a material that works well for energy conversion or storage is like creating a happy marriage,” said Nenad Markovic, an Argonne materials scientist and author of the study. “In our case, we found that a dynamic partnership between two different materials helped us integrate competing concerns.”

    Scientists searching for new catalysts have scoured the periodic table to find the right elements or combinations of elements to maximize a catalyst’s activity in water-splitting reactions, as well as the durability of the active sites on its surface. Finding materials that are both stable and active, however, has been a challenge.

    “More active catalysts tend to be less stable,” Markovic said. “Those that seem to work twice as well usually work only half as long. It is becoming obvious that designing active catalysts is not enough — we need to have not only active, but also stable, materials.”

    For the new catalyst, Markovic and his colleagues turned to iridium, a metal most commonly associated with meteorites. As a thin film, iridium is catalytically active, but as it reacts over time with an electrolyte environment, iridium atoms become oxidized. During this process, some of them leave the catalyst’s surface through corrosion, increasingly impairing its performance.

    The research team worked to prevent the oxidation by reorganizing the iridium’s structure. To help stabilize and activate iridium, they alloyed it with its neighbor on the periodic table, osmium.

    Unlike iridium, osmium is neither catalytically active nor stable, but it did offer a key benefit. After alloying the osmium and iridium together, the researchers then de-alloyed the two metals, leaving behind only a reconfigured structure of three-dimensional iridium nanopores.

    “Without the osmium, the iridium would never achieve this state,” Markovic said. “We needed to introduce and then remove the osmium to get a form of iridium that was both active and stable.”

    Markovic said each nanopore’s enhanced catalytic stability is due to the small volume of electrolyte within a pore becoming quickly saturated with iridium ions so that surface atoms stop dissolving, in much the same way that it is easier to saturate a teacup of water with sugar than a 10-gallon jug.

    While the nanopore’s structure addressed the need for a stable, active catalyst, it was another facet of the iridium’s reconfiguration that helped boost the material’s electron conductivity. Under operational conditions, the porous catalyst actually forms a unique shell of less-conductive iridium oxide around its highly conductive iridium metal interior. This way, electrons can move easily through most of the catalyst to reach the surface, where the water molecule waits on electrons to initiate the water-splitting reaction.

    “Essentially, we’re trying to find a way to send electrons through on the ‘expressway,’ rather than making them take the side roads,” Markovic said. “This core-shell configuration [of the nanoporous material] allows us to do that.”

    See the full article here .

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    Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation’s first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America’s scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science. For more visit http://www.anl.gov.

    The Advanced Photon Source at Argonne National Laboratory is one of five national synchrotron radiation light sources supported by the U.S. Department of Energy’s Office of Science to carry out applied and basic research to understand, predict, and ultimately control matter and energy at the electronic, atomic, and molecular levels, provide the foundations for new energy technologies, and support DOE missions in energy, environment, and national security. To learn more about the Office of Science X-ray user facilities, visit http://science.energy.gov/user-facilities/basic-energy-sciences/.

    Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy’s Office of Science

    Argonne Lab Campus

     
  • richardmitnick 10:06 am on June 23, 2017 Permalink | Reply
    Tags: , , , Catalysis, , Improve the performance of fuel cells that run on hydrogen fuel but can be poisoned by CO, , Peking University, Taiyuan University of Technology China   

    From BNL: “New Efficient, Low-Temperature Catalyst for Converting Water and CO to Hydrogen Gas and CO2” 

    Brookhaven Lab

    June 22, 2017
    Karen McNulty Walsh
    kmcnulty@bnl.gov
    (631) 344-8350

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

    Low-temperature “water gas shift” reaction produces high levels of pure hydrogen for potential applications, including fuel cells.

    1
    Brookhaven Lab chemists Ping Liu and José Rodriguez helped to characterize structural and mechanistic details of a new low-temperature catalyst for producing high-purity hydrogen gas from water and carbon monoxide. No image credit.

    Scientists have developed a new low-temperature catalyst for producing high-purity hydrogen gas while simultaneously using up carbon monoxide (CO). The discovery—described in a paper set to publish online in the journal Science on Thursday, June 22, 2017—could improve the performance of fuel cells that run on hydrogen fuel but can be poisoned by CO.

    “This catalyst produces a purer form of hydrogen to feed into the fuel cell,” said José Rodriguez, a chemist at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory. Rodriguez and colleagues in Brookhaven’s Chemistry Division—Ping Liu and Wenqian Xu—were among the team of scientists who helped to characterize the structural and mechanistic details of the catalyst, which was synthesized and tested by collaborators at Peking University in an effort led by Chemistry Professor Ding Ma.

    Because the catalyst operates at low temperature and low pressure to convert water (H2O) and carbon monoxide (CO) to hydrogen gas (H2) and carbon dioxide (CO2), it could also lower the cost of running this so-called “water gas shift” reaction.

    “With low temperature and pressure, the energy consumption will be lower and the experimental setup will be less expensive and easier to use in small settings, like fuel cells for cars,” Rodriguez said.

    The gold-carbide connection

    The catalyst consists of clusters of gold nanoparticles layered on a molybdenum-carbide substrate. This chemical combination is quite different from the oxide-based catalysts used to power the water gas shift reaction in large-scale industrial hydrogen production facilities.

    “Carbides are more chemically reactive than oxides,” said Rodriguez, “and the gold-carbide interface has good properties for the water gas shift reaction; it interacts better with water than pure metals.”

    2
    Wenqian Xu and José Rodriguez of Brookhaven Lab and Siyu Yao, then a student at Peking University but now a postdoctoral research fellow at Brookhaven, conducted operando x-ray diffraction studies of the gold-molybdenum-carbide catalyst over a range of temperatures (423 Kelvin to 623K) at the National Synchrotron Light Source (NSLS) at Brookhaven Lab. The study revealed that at temperatures above 500K, molybdenum-carbide transforms to molybdenum oxide, with a reduction in catalytic activity. No image credit

    “The group at Peking University discovered a new synthetic method, and that was a real breakthrough,” Rodriguez said. “They found a way to get a specific phase—or configuration of the atoms—that is highly active for this reaction.”

    Brookhaven scientists played a key role in deciphering the reasons for the high catalytic activity of this configuration. Rodriguez, Wenqian Xu, and Siyu Yao (then a student at Peking University but now a postdoctoral research fellow at Brookhaven) conducted structural studies using x-ray diffraction at the National Synchrotron Light Source (NSLS) while the catalyst was operating under industrial or technical conditions.

    BNL NSLS

    These operando experiments revealed crucial details about how the structure changed under different operating conditions, including at different temperatures.

    With those structural details in hand, Zhijun Zuo, a visiting professor at Brookhaven from Taiyuan University of Technology, China, and Brookhaven chemist Ping Liu helped to develop models and a theoretical framework to explain why the catalyst works the way it does, using computational resources at Brookhaven’s Center for Functional Nanomaterials (CFN).

    “We modeled different interfaces of gold and molybdenum carbide and studied the reaction mechanism to identify exactly where the reactions take place—the active sites where atoms are binding, and how bonds are breaking and reforming,” she said.

    Additional studies at Oak Ridge National Laboratory’s Center for Nanophase Materials Sciences (CNMS), the Advanced Light Source (ALS) at Lawrence Berkeley National Laboratory, and two synchrotron research facilities in China added to the scientists’ understanding.

    “This is a multipart complex reaction,” said Liu, but she noted one essential factor: “The interaction between the gold and the carbide substrate is very important. Gold usually bonds things very weakly. With this synthesis method we get stronger adherence of gold to molybdenum carbide in a controlled way.”

    That configuration stabilizes the key intermediate that forms as the reaction proceeds, and the stability of that intermediate determines the rate of hydrogen production, she said.

    The Brookhaven team will continue to study this and other carbide catalysts with new capabilities at the National Synchrotron Light Source II (NSLS-II), a new facility that opened at Brookhaven Lab in 2014, replacing NSLS and producing x-rays that are 10,000 times brighter.

    BNL NSLS-II

    With these brighter x-rays, the scientists hope to capture more details of the chemistry in action, including details of the intermediates that form throughout the reaction process to validate the theoretical predictions made in this study.

    The work at Brookhaven Lab was funded by the U.S. DOE Office of Science.

    Additional funders for the overall research project include: the National Basic Research Program of China, the Chinese Academy of Sciences, National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities of China, and the U.S. National Science Foundation.

    NSLS, NSLS-II, CFN, CNMS, and ALS are all DOE Office of Science User Facilities.

    See the full article here .

    Please help promote STEM in your local schools.

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    BNL Campus

    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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