From Berkeley Lab: “…Black Nanoparticles Could Play Key Role in Clean Energy Photocatalysis”

Berkeley Lab

“A unique atomic-scale engineering technique for turning low-efficiency photocatalytic “white” nanoparticles of titanium dioxide into high-efficiency “black” nanoparticles could be the key to clean energy technologies based on hydrogen.

Samuel Mao, a scientist who holds joint appointments with Berkeley Lab’s Environmental Energy Technologies Division and the University of California at Berkeley, leads the development of a technique for engineering disorder into the nanocrystalline structure of the semiconductor titanium dioxide. This turns the naturally white crystals black in color, a sign that the crystals are now able to absorb infrared as well as visible and ultraviolet light. The expanded absorption spectrum substantially improves the efficiency with which black titanium dioxide can use sunlight to split water molecules for the production of hydrogen.

Berkeley Lab’s Samuel Mao used disorder engineering to transform titanium nanocrystals into highly efficient solar hydrogen photocatalysts, a transformation marked by turning the crystals from white to black. (Photo by Roy Kaltschmidt)

‘We have demonstrated that black titanium dioxide nanoparticles are capable of generating hydrogen through solar-driven photocatalytic reactions with a record-high efficiency,’ Mao said in a talk at the American Chemical Society (ACS)’s national meeting in New Orleans.

‘The synthesis of black titanium dioxide nanoparticles was based on a hydrogenation process in which white titanium dioxide nanocrystals were subjected to high pressure hydrogen gas,’ said Mao. ‘The unique disordered structure creates a photocatalyst that is both durable and efficient, and gives titanium dioxide, one of the most-studied of all oxide materials, a renewed potential.’”

See the full article here.

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

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From PPPL Lab: “US ITER is a strong contributor in plan to enhance international sharing of prime ITER real estate”

March 28, 2013
Lynne Degitz

“When the ITER experimental fusion reactor begins operation in the 2020s, over 40 diagnostic tools will provide essential data to researchers seeking to understand plasma behavior and optimize fusion performance. But before the ITER tokamak is built, researchers need to determine an efficient way of fitting all of these tools into a limited number of shielded ports that will protect the delicate diagnostic hardware and other parts of the machine from neutron flux and intense heat. A port plug integration proposal developed with the US ITER diagnostics team has helped the international ITER collaboration arrive at a clever solution for safely housing all of the tokamak diagnostic devices.

‘Before horizontal or vertical modules were proposed, diagnostic teams were not constrained to any particular design space. When we started working on this, we suggested that there be some type of modular approach,’ said Russ Feder, a US ITER diagnostics contributor and Senior Mechanical Engineer at Princeton Plasma Physics Laboratory. ‘Originally, we proposed four horizontal drawers for each port plug. But then analysis of electromagnetic forces on these horizontal modules showed that forces were too high and the project switched to the three vertical modules.’”

The proposal has been formalized by two ITER procurement agreements in late 2012 between US ITER, based at Oak Ridge National Laboratory, and the ITER Organization; other ITER partners are expected to make similar agreements this year.”

PPPL’s Russell Feder, left, and David Johnson developed key features for a modular approach to housing the extensive diagnostic systems that will be installed on the ITER tokamak. (Photo credit: Elle Starkman/PPPL Office of Communications)

See the full article here.

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

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From M.I.T.: “New solar-cell design based on dots and wires”

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MIT researchers improve efficiency of quantum-dot photovoltaic system by adding a forest of nanowires.

March 25, 2013
David L. Chandler

“Using exotic particles called quantum dots as the basis for a photovoltaic cell is not a new idea, but attempts to make such devices have not yet achieved sufficiently high efficiency in converting sunlight to power. A new wrinkle added by a team of researchers at MIT — embedding the quantum dots within a forest of nanowires — promises to provide a significant boost.”

Scanning Electron Microscope images show an array of zinc-oxide nanowires (top) and a cross-section of a photovoltaic cell made from the nano wires, interspersed with quantum dots made of lead sulfide (dark areas). A layer of gold at the top (light band) and a layer of indium-tin-oxide at the bottom (lighter area) form the two electrodes of the solar cell.
Images courtesy of Jean, et al/Advanced Materials

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From Berkeley Lab: “Berkeley Lab Researchers Use Metamaterials to Observe Giant Photonic Spin Hall Effect”

Berkeley Lab

March 21, 2013
Lynn Yarris

“Researchers with the U.S. Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have once again demonstrated the incredible capabilities of metamaterials – artificial nanoconstructs whose optical properties arise from their physical structure rather than their chemical composition. Engineering a unique two-dimensional sheet of gold nanoantennas, the researchers were able to obtain the strongest signal yet of the photonic spin Hall effect, an optical phenomenon of quantum mechanics that could play a prominent role in the future of computing.

Light propagating through a metamaterial follows a curved trajectory that drags light with different circular polarization in opposite transverse directions to produce a giant photonic Spin Hall effect.

‘With metamaterial, we were able to greatly enhance a naturally weak effect to the point where it was directly observable with simple detection techniques,’ said Xiang Zhang, a faculty scientist with Berkeley Lab’s Materials Sciences Division who led this research. ‘We also demonstrated that metamaterials not only allow us to control the propagation of light but also allows control of circular polarization. This could have profound consequences for information encoding and processing.’

Zhang is the corresponding author of a paper describing this work in the journal Science. The paper is titled Photonic Spin Hall Effect at Metasurfaces. Co-authors are Xiaobo Yin, Ziliang Ye, Jun Sun Rho and Yuan Wang.

Metamaterials have garnered a lot of attention in recent years because their unique structure affords electromagnetic properties unattainable in nature. For example, a metamaterial can have a negative index of refraction, the ability to bend light backwards, unlike all materials found in nature, which bend light forward. Zhang, who holds the Ernest S. Kuh Endowed Chair Professor of Mechanical Engineering at the University of California (UC) Berkeley, where he also directs the National Science Foundation’s Nano-scale Science and Engineering Center, has been at the forefront of metamaterials research.

See the full article here.

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

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From SLAC: “Materials Scientists Make Solar Energy Chip 100 Times More Efficient”

March 19, 2013
Mike Ross

“Scientists working at the Stanford Institute for Materials and Energy Sciences (SIMES) have improved an innovative solar-energy device to be about 100 times more efficient than its previous design in converting the sun’s light and heat into electricity.

‘This is a major step toward making practical devices based on our technique for harnessing both the light and heat energy provided by the sun,’ said Nicholas Melosh, associate professor of materials science and engineering at Stanford and a researcher with SIMES, a joint SLAC/Stanford institute.

Nick Melosh (left), associate professor of materials science and engineering at Stanford and a researcher with SIMES, and graduate student Jared Schwede. (Credit: Brad Plummer / SLAC)

The new device is based on the photon-enhanced thermionic emission (PETE) process first demonstrated in 2010 by a group led by Melosh and SIMES colleague Zhi-Xun Shen, who is SLAC’s advisor for science and technology. In a report last week in Nature Communications, the group described how they improved the device’s efficiency from a few hundredths of a percent to nearly 2 percent, and said they expect to achieve at least another 10-fold gain in the future.”

Part of a 2-inch-diameter gallium-arsenide wafer used as a base for photon-enhanced thermionic emission chips. (Credit: Brad Plummer / SLAC)

This is exciting news for Clean Energy. See the full article here.

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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From SLAC Lab: “Breakthrough Research Shows Chemical Reaction in Real Time”

March 14, 2013
No Writer Credit

“The ultrafast, ultrabright X-ray pulses of the Linac Coherent Light Source (LCLS) have enabled unprecedented views of a catalyst in action, an important step in the effort to develop cleaner and more efficient energy sources.

How LCLS views surface chemistry (Credit: Hirohito Ogasawara / SLAC National Accelerator Laboratory)

Scientists at the U.S. Department of Energy’s (DOE) SLAC National Accelerator Laboratory used LCLS, together with computerized simulations, to reveal surprising details of a short-lived early state in a chemical reaction occurring at the surface of a catalyst sample. The study offers important clues about how catalysts work and launches a new era in probing surface chemistry as it happens.

‘To study a reaction like this in real time is a chemist’s dream,’ said Anders Nilsson, deputy director for the Stanford and SLAC SUNCAT Center for Interface Science and Catalysis and a leading author in the research, published March 15 in Science. ‘We are really jumping into the unknown.’”

See the full article here.

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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From PPPL: “Rajesh Maingi adds a new strategic dimension to fusion and plasma physics research”

March 14, 2013
John Greenwald

“Physicist Rajesh Maingi remembers nearly everything. Results of experiments he did 20 years ago play back instantly in his mind, as do his credit card and bank account numbers.

Rajesh Maingi. (Photo credit: Elle Starkman )

Maingi brings his expertise to the new position of manager of edge physics and plasma-facing components at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL). The recently created post calls for coordinating all Laboratory research on the volatile edge of the plasma, which must be carefully controlled for fusion to take place, and on the crucial boundary between the plasma and the interior surfaces of a tokamak.

Tokamak

At PPPL

The strategic position adds a new dimension to research at PPPL. ‘We’ve decided to pull all our activities in this area together and plan how to use them to make an impact in the fusion community and the world,’ said Michael Zarnstorff, deputy director for research at the Laboratory. ‘Rajesh is well-known around the world, particularly in tokamak physics. He has experience and perspective and strategic vision, and we see him as a great opportunity for the Lab.’”

See the full article here.

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

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FRom PPPL: "A fast new method for measuring hard-to-diagnose 3D plasmas in fusion facilities"

March 12, 2013
John Greenwald

“Scientists at the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) and the National Institute for Fusion Science (NIFS) in Japan have developed a rapid method for meeting a key challenge for fusion science. The challenge has been to simulate the diagnostic measurement of plasmas produced by twisting, or 3D, magnetic fields in fusion facilities. While such fields characterize facilities called stellarators, otherwise symmetric, or 2D, facilities such as tokamaks also can benefit from 3D fields.

A cutaway view of the ITER Project Tokamak reactor.

Researchers led by PPPL physicist Sam Lazerson have now created a computer code that simulates the required diagnostics, and have validated the code on the Large Helical Device stellarator in Japan. Called ‘Diagno v2.0,’ the new program utilizes information from previous codes that simulate 3D plasmas without the diagnostic measurements. The addition of this new capability could, with further refinement, enable physicists to predict the outcome of 3D plasma experiments with a high degree of accuracy.

A simulated plasma in the Large Helical Device showing the thin blue saddle coils that researchers used to make diagnostic measurements with the new computer code. (Photo credit: Graphic by Sam Lazerson)

Lazerson and co-authors Satoru Sakakibara and Yasuhiro Suzuki of NIFS have published their paper online in the February issue of Plasma Physics and Controlled Fusion http://dx.doi.org/10.1088/0741-3335/55/2/025014. The journal also is using a Lazerson graphic of a simulated plasma on the cover of its print edition. “

See the full article here.

Princeton Plasma Physics Laboratory is a U.S. Department of Energy national laboratory managed by Princeton University.

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From SLAC: “Unexpected Allies Help Bacteria Clean Uranium From Groundwater”

March 7, 2013
Lori Ann White

“Since 2009, SLAC scientist John Bargar has led a team using synchrotron-based X-ray techniques to study bacteria that help clean uranium from groundwater in a process called bioremediation. Their initial goal was to discover how the bacteria do it and determine the best way to help, but during the course of their research the team made an even more important discovery: Nature thinks bigger than that.

From left to right: Sam Webb, John Bargar and Juan Lezama-Pacheco used X-rays from the Stanford Synchrotron Radiation Lightsource to discover Nature’s housecleaning secrets. Since the housecleaning involves uranium, their curiosity may have important benefits. (Credit: Matt Beardsley)

The researchers discovered that bacteria don’t necessarily go straight for the uranium, as was often thought to be the case. The bacteria make their own, even tinier allies – nanoparticles of a common mineral called iron sulfide. Then, working together, the bacteria and the iron sulfide grab molecules of a highly soluble form of uranium known as U(VI), or hexavalent uranium, and transform them into U(IV), a less-soluble form that’s much less likely to spread through the water table. According to Barger, this newly discovered partnership may be the basis of a global geochemical process that forms deposits of uranium ore.

And it’s all done using one of the most basic types of chemical reactions known: oxidation and reduction, commonly known as ‘redox.’ Redox reactions can be thought of as the transfer of electrons from donor atoms to atoms that are hungry for electrons, and they are a primary source of chemical energy for both living and non-living processes. Photosynthesis involves redox reactions, as does cell respiration. Iron oxidizes to form rust; batteries depend on redox reactions to store and release energy.

‘Redox transitions are a very fundamental process,’ Bargar said. ‘It’s the stuff of life. It’s how you breathe.’”

The study, published Monday in the Proceeding of the National Academy of Sciences, was conducted at the Old Rifle site on the Colorado River, a former uranium ore processing site in the town of Rifle, Colo. The aquifer at the site is contaminated with uranium and is the focus of bioremediation field studies conducted by a larger team of scientists at Lawrence Berkeley National Laboratory and funded by the Department of Energy’s Office of Biological and Environmental Research. As part of their study, the LBNL team added acetate – essentially vinegar – to the aquifer in a series of injection wells to “feed the bugs,” as Bargar put it, allowing acetate to flow throughout the aquifer around the wells.

See the full article here.

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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From Livermore Lab: “National Academies recommend high priority for work on Lawrence Livermore’s National Ignition Facility”

Lawrence Livermore National Laboratory

02/21/2013
Breanna Bishop

“ A report issued by the National Research Council highlights the significant impact of successful development of inertial fusion energy (IFE), and recommends priorities for future research in this area.

A view from the bottom of the chamber. Pulses from NIF’s high-powered lasers race toward the Target Bay at the speed of light. They arrive at the center of the target chamber within a few trillionths of a second of each other, aligned to the accuracy of the diameter of a human hair.

As noted in this National Academies’ report, ‘The potential benefits of inertial confinement fusion energy (abundant fuel, minimal greenhouse gas emissions, limited high-level radioactive waste requiring long-term disposal) provide a compelling rationale for establishing inertial fusion energy R&D as part of the long-term U.S. energy R&D portfolio.’

Research into IFE is a key objective of Lawrence Livermore National Laboratory’s National Ignition Facility (NIF) — the world’s premier research facility in this area of science and technology. The NIF was built by the National Nuclear Security Administration (NNSA) primarily to provide data in support of its defense programs, but also has broad applications in basic science and fusion energy.

The National Academies state that ‘The National Ignition Facility, designed for stockpile stewardship applications, also is of great potential importance for advancing the technical basis for inertial fusion energy (IFE) research,’ and that the target physics programs on the NIF (and related facilities) ‘should receive continued high priority.’”

See the full article here.

Operated by Lawrence Livermore National Security, LLC, for the Department of Energy’s National Nuclear Security
Administration

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