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Scientists at Ames Laboratory have discovered a method for making smaller, more efficient intermetallic nanoparticles for fuel cell applications, and which also use less of the expensive precious metal platinum. The researchers succeeded by overcoming some of the technical challenges presented in the fabrication of the platinum-zinc nanoparticles with an ordered lattice structure, which function best at the small sizes in which the chemically reactive surface area is highest in proportion to the particle volume. "That surface-to-volume ratio is important in getting the most out of an intermetallic nanoparticle," said Wenyu Huang, Ames Laboratory scientist and assistant professor of Chemistry at Iowa State University. "The smaller the particle, the more surface there is, and more surface area increases the catalytic activity." But the high temperature of the annealing process necessary to form intermetallic nanoparticles often defeats the goal of achieving a small size. "High-temperature annealing can cause the particles to aggregate or clump, and produces larger sizes of particles that have less available surface and aren't as reactive. So, just the steps necessary to produce them can defeat their ultimate chemical performance," said Huang. To prevent aggregation from occurring during the heating process, Huang's research group first used carbon nanotubes as a support for the PtZn nanoparticles, and then coated them with a sacrificial mesoporous silica shell for the high-temperature annealing to form the intermetallic structures. A chemical etching process then removes the silica shell afterward. The resulting final product of uniform 3.2 nm platinum-zinc particles not only yielded twice the catalytic activity per surface site, that surface area saw ten times the catalytic activity of larger particles containing the same amount of platinum. The discovery was made possible in part by the capabilities of a new Titan scanning electron microscope at Ames Laboratory's Sensitive Instrument Facility, jointly funded by the Department of Energy and Iowa State University. "Being able to see the distributions of the material at atomic level with our new microscope has made an enormous positive impact on the Laboratory's capabilities to fine-tune materials," said Lin Zhou, associate scientist and instrument lead for the Sensitive Instrument Facility. "It's a much more immediate process, being able to collaborate directly with the fabrication scientists in-house. Based on the results and suggestions we provide, they can improve the material, we can characterize it yet again, and the discovery cycle is much faster." The research is further discussed in a paper, "Sub-4 nm PtZn Intermetallic Nanoparticles for Enhanced Mass and Specific Activities in Catalytic Electrooxidation Reaction", authored by Zhiyuan Qi, Chaoxian Xiao, Cong Liu, Tian-Wei Goh, Lin Zhou, Raghu Maligal-Ganesh, Yuchen Pei, Xinle Li, Larry A. Curtiss, and Wenyu Huang and published in the Journal of the American Chemical Society. The work was funded by the National Science Foundation, Iowa State University, Ames Laboratory Directed Research and Development (LDRD) funds, and the U.S. Department of Energy's Office of Science. Computational work was supported by the Laboratory Computing Resource Center and the Center for Nanoscale Materials, both at Argonne National Laboratory. Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.


News Article | May 10, 2017
Site: www.eurekalert.org

Iver Anderson, senior metallurgist at the U.S. Department of Energy's Ames Laboratory will be inducted into the National Inventors Hall of Fame (NIHF) on May 4, 2017. Anderson joins 14 other inductees (including 6 historical inductees) who will be honored in an illumination ceremony at the NIHF Museum in Alexandria, Va., on May 3 and then presented awards in the 45th Annual Inventors Hall of Fame Induction Ceremony on May 4. The induction ceremony will be held at the National Building Museum in Washington, D.C. "Each year, we induct a new class of industry pioneers into the National Inventors Hall of Fame who have conceived and patented innovations to further our nation, and this year's class is no exception," said NIHF CEO, Mike Oister. "This year's inductees have provided solutions to life's common problems and as a result, they've enhanced our lives." Anderson is being recognized for developing lead-free solder, an alloy of tin, silver and copper that is now used worldwide in most consumer electronic devices, such as smart phones, laptops and tablets. As a result of Anderson's discovery, well over 50,000 tons of lead per year will no longer be released into the environment, worldwide, according to the NIHF. Anderson, who is also an adjunct professor in the Materials Science and Engineering Department at Iowa State University, says he is humbled and pleased to have been chosen for this prestigious award. "Many scientists spend years working on a product they hope will one day make it into the marketplace," said Anderson. "This award is confirmation of the hard work that was put in by my team and me to the betterment of our society." Called the greatest celebration of American innovation, the NIHF was founded in 1973 in partnership with the U.S. Patent and Trademark Office and is dedicated to recognizing inventors and invention, promoting creativity, and advancing the spirit of innovation and entrepreneurship. The 2017 inductees, as part of their involvement in NIHF, will help foster the development of America's next generation of innovators by inspiring the curriculum of Camp Invention, the nation's premier summer enrichment day camp, which encourages innovation in youth and focuses on science, technology, engineering and math. Inductees will also serve as judges for the Collegiate Inventors Competition, a national platform for college and university students, showcasing their emerging ideas and technologies that will benefit our society in the future. "Iver's colleagues at Ames Laboratory and ISU salute his wonderful record of invention that has led to this award," said Adam Schwartz, Ames Laboratory director. "We look forward to seeing additional inventions from Iver over the next several years." For more information on the National Inventors Hall of Fame, go to: http://www. . Ames Laboratory is a DOE Office of Science national laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems. DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.


The researchers succeeded by overcoming some of the technical challenges presented in the fabrication of the platinum-zinc nanoparticles with an ordered lattice structure, which function best at the small sizes in which the chemically reactive surface area is highest in proportion to the particle volume. "That surface-to-volume ratio is important in getting the most out of an intermetallic nanoparticle," said Wenyu Huang, Ames Laboratory scientist and assistant professor of Chemistry at Iowa State University. "The smaller the particle, the more surface there is, and more surface area increases the catalytic activity." But the high temperature of the annealing process necessary to form intermetallic nanoparticles often defeats the goal of achieving a small size. "High-temperature annealing can cause the particles to aggregate or clump, and produces larger sizes of particles that have less available surface and aren't as reactive. So, just the steps necessary to produce them can defeat their ultimate chemical performance," said Huang. To prevent aggregation from occurring during the heating process, Huang's research group first used carbon nanotubes as a support for the PtZn nanoparticles, and then coated them with a sacrificial mesoporous silica shell for the high-temperature annealing to form the intermetallic structures. A chemical etching process then removes the silica shell afterward. The resulting final product of uniform 3.2 nm platinum-zinc particles not only yielded twice the catalytic activity per surface site, that surface area saw ten times the catalytic activity of larger particles containing the same amount of platinum. The discovery was made possible in part by the capabilities of a new Titan scanning electron microscope at Ames Laboratory's Sensitive Instrument Facility, jointly funded by the Department of Energy and Iowa State University. "Being able to see the distributions of the material at atomic level with our new microscope has made an enormous positive impact on the Laboratory's capabilities to fine-tune materials," said Lin Zhou, associate scientist and instrument lead for the Sensitive Instrument Facility. "It's a much more immediate process, being able to collaborate directly with the fabrication scientists in-house. Based on the results and suggestions we provide, they can improve the material, we can characterize it yet again, and the discovery cycle is much faster." The research is further discussed in a paper, "Sub-4 nm PtZn Intermetallic Nanoparticles for Enhanced Mass and Specific Activities in Catalytic Electrooxidation Reaction" published in the Journal of the American Chemical Society. Explore further: Heat treatment offers precise control over catalytic activity of metal sulfide nanoparticles More information: Zhiyuan Qi et al. Sub-4 nm PtZn Intermetallic Nanoparticles for Enhanced Mass and Specific Activities in Catalytic Electrooxidation Reaction, Journal of the American Chemical Society (2017). DOI: 10.1021/jacs.6b12780


« Global Bioenergies, Clariant and INEOS in €16.4M EU-funded project to demonstrate the production of isobutene derivatives from straw | Main | Karsan unveiling “Buy America” CNG bus at UTIP World Global Transport Summit » Researchers at the US Department of Energy’s (DOE’s) Ames Laboratory have discovered a method for making smaller, more efficient intermetallic nanoparticles for fuel cell applications, and which also use less of the expensive precious metal platinum. A paper on the work is published in the Journal of the American Chemical Society. The researchers succeeded by overcoming some of the technical challenges presented in the fabrication of the platinum-zinc nanoparticles with an ordered lattice structure, which function best at the small sizes in which the chemically reactive surface area is highest in proportion to the particle volume. Tremendous endeavors have been devoted to the investigation of intermetallic nanomaterials, particularly Pt‐based, as fuel cell electrocatalysts with the aim of decreasing Pt usage, increasing poisoning tolerance and improving the catalysts activities and stabilities. A great many scientific efforts have been devoted to the preparation of Pt‐based alloys and intermetallic compounds … in the electro‐oxidation of methanol or formic acid and electro‐reduction of oxygen. The surface-to-volume ratio is important in getting the most out of an intermetallic nanoparticle, said corresponding author Wenyu Huang, Ames Laboratory scientist and assistant professor of Chemistry at Iowa State University. “The smaller the particle, the more surface there is, and more surface area increases the catalytic activity.” But the high temperature of the annealing process necessary to form intermetallic nanoparticles often defeats the goal of achieving a small size. To prevent aggregation from occurring during the heating process, Huang’s research group first used carbon nanotubes as a support for the PtZn nanoparticles, and then coated them with a sacrificial mesoporous silica shell for the high-temperature annealing to form the intermetallic structures. A chemical etching process then removes the silica shell afterward. The resulting final product of uniform 3.2 nm platinum-zinc particles not only yielded twice the catalytic activity per surface site, that surface area saw ten times the catalytic activity of larger particles containing the same amount of platinum. The discovery was made possible in part by the capabilities of a new Titan scanning electron microscope at Ames Laboratory’s Sensitive Instrument Facility, jointly funded by the Department of Energy and Iowa State University. The work was funded by the National Science Foundation, Iowa State University, Ames Laboratory Directed Research and Development (LDRD) funds, and the US Department of Energy’s Office of Science. Computational work was supported by the Laboratory Computing Resource Center and the Center for Nanoscale Materials, both at Argonne National Laboratory.


News Article | April 11, 2017
Site: www.cemag.us

Researchers looking for ways to regenerate nerves can have a hard time obtaining key tools of their trade. Schwann cells are an example. They form sheaths around axons, the tail-like parts of nerve cells that carry electrical impulses. They promote regeneration of those axons. And they secrete substances that promote the health of nerve cells. In other words, they’re very useful to researchers hoping to regenerate nerve cells, specifically peripheral nerve cells, those cells outside the brain and spinal cord. But Schwann cells are hard to come by in useful numbers. So researchers have been taking readily available and noncontroversial mesenchymal stem cells (also called bone marrow stromal stem cells that can form bone, cartilage and fat cells) and using a chemical process to turn them, or as researchers say, differentiate them into Schwann cells. But it’s an arduous, step-by-step and expensive process. Researchers at Iowa State University are exploring what they hope will be a better way to transform those stem cells into Schwann-like cells. They’ve developed a nanotechnology that uses inkjet printers to print multi-layer graphene circuits and also uses lasers to treat and improve the surface structure and conductivity of those circuits. It turns out mesenchymal stem cells adhere and grow well on the treated circuit’s raised, rough and 3D nanostructures. Add small doses of electricity — 100 millivolts for 10 minutes per day over 15 days — and the stem cells become Schwann-like cells. The researchers’ findings are featured on the front cover of the scientific journal Advanced Healthcare Materials. Jonathan Claussen, an Iowa State assistant professor of mechanical engineering and an associate of the U.S. Department of Energy’s Ames Laboratory, is lead author. Suprem Das, a postdoctoral research associate in mechanical engineering and an associate of the Ames Laboratory; and Metin Uz, a postdoctoral research associate in chemical and biological engineering, are first authors. The project is supported by funds from the Roy J. Carver Charitable Trust, the U.S. Army Medical Research and Materiel Command, Iowa State’s College of Engineering, the department of mechanical engineering and the Carol Vohs Johnson Chair in Chemical and Biological Engineering held by Surya Mallapragada, an Anson Marston Distinguished Professor in Engineering, an associate of the Ames Laboratory and a paper co-author. “This technology could lead to a better way to differentiate stem cells,” Uz says. “There is huge potential here.” The electrical stimulation is very effective, differentiating 85 percent of the stem cells into Schwann-like cells compared to 75 percent by the standard chemical process, according to the research paper. The electrically differentiated cells also produced 80 nanograms per milliliter of nerve growth factor compared to 55 nanograms per milliliter for the chemically treated cells. The researchers report the results could lead to changes in how nerve injuries are treated inside the body. “These results help pave the way for in vivo peripheral nerve regeneration where the flexible graphene electrodes could conform to the injury site and provide intimate electrical stimulation for nerve cell regrowth,” the researchers wrote in a summary of their findings. The paper reports several advantages to using electrical stimulation to differentiate stem cells into Schwann-like cells: A key to making it all work is a graphene inkjet printing process developed in Claussen’s research lab. The process takes advantages of graphene’s wonder-material properties — it’s a great conductor of electricity and heat, it’s strong, stable and biocompatible — to produce low-cost, flexible and even wearable electronics. But there was a problem: once graphene electronic circuits were printed, they had to be treated to improve electrical conductivity. That usually meant high temperatures or chemicals. Either could damage flexible printing surfaces including plastic films or paper. Claussen and his research group solved the problem by developing computer-controlled laser technology that selectively irradiates inkjet-printed graphene oxide. The treatment removes ink binders and reduces graphene oxide to graphene – physically stitching together millions of tiny graphene flakes. The process makes electrical conductivity more than a thousand times better. The collaboration of Claussen’s group of nanoengineers developing printed graphene technologies and Mallapragada’s group of chemical engineers working on nerve regeneration began with some informal conversations on campus. That led to experimental attempts to grow stem cells on printed graphene and then to electrical stimulation experiments. “We knew this would be a really good platform for electrical stimulation,” Das says. “But we didn’t know it would differentiate these cells.” But now that it has, the researchers say there are new possibilities to think about. The technology, for example, could one day be used to create dissolvable or absorbable nerve regeneration materials that could be surgically placed in a person’s body and wouldn’t require a second surgery to remove.


News Article | April 25, 2017
Site: www.materialstoday.com

Iowa State University researchers (left to right: Metin Uz, Suprem Das, Surya Mallapragada and Jonathan Claussen) are developing technologies to promote nerve regrowth. The monitor shows mesenchymal stem cells (white) aligned along graphene circuits (black). Photo: Christopher Gannon/Iowa State University.Researchers looking for ways to regenerate nerves can have a hard time obtaining the key tools of their trade. Take Schwann cells, which form sheaths around axons – the tail-like parts of nerve cells that carry electrical impulses – and also promote regeneration of those axons and secrete substances that promote the health of nerve cells. In other words, they're very useful to researchers hoping to regenerate nerve cells, especially peripheral nerve cells outside the brain and spinal cord. But Schwann cells are hard to come by in useful numbers. So researchers have been taking readily-available and non-controversial mesenchymal stem cells (also known as bone marrow stromal stem cells, because they can form bone, cartilage and fat cells) and using a chemical process to turn them, or differentiate them, into Schwann cells. But it's an arduous, step-by-step and expensive process. Researchers at Iowa State University are now exploring what they hope will be a better way to transform mesenchymal stem cells into Schwann-like cells. They've developed a nanotechnology-based process that involves using inkjet printers to print multi-layer graphene circuits, and then lasers to treat and improve the surface structure and conductivity of those circuits. It turns out that mesenchymal stem cells adhere and grow well on the treated circuit's raised, rough and three-dimensional (3D) nanostructures. Add small doses of electricity – 100 millivolts for 10 minutes per day over 15 days – and the stem cells differentiate into Schwann-like cells. The researchers' findings are reported in a paper in Advanced Healthcare Materials, and are also featured on the front cover. Jonathan Claussen, an Iowa State assistant professor of mechanical engineering and an associate at the US Department of Energy's Ames Laboratory, is lead author. Suprem Das, a postdoctoral research associate in mechanical engineering and an associate of the Ames Laboratory, and Metin Uz, a postdoctoral research associate in chemical and biological engineering, are first authors. "This technology could lead to a better way to differentiate stem cells," said Uz. "There is huge potential here." The electrical stimulation is very effective, differentiating 85% of the stem cells into Schwann-like cells, compared to 75% for the standard chemical process. The electrically-differentiated cells also produced 80 nanograms per milliliter of nerve growth factor compared to 55 nanograms per milliliter for the chemically-treated cells. The researchers report that the results could lead to changes in how nerve injuries are treated inside the body. "These results help pave the way for in vivo peripheral nerve regeneration where the flexible graphene electrodes could conform to the injury site and provide intimate electrical stimulation for nerve cell regrowth," the researchers wrote in a summary of their findings. The paper reports several advantages to using electrical stimulation to differentiate stem cells into Schwann-like cells. These include: doing away with the arduous steps of chemical processing; reducing costs by eliminating the need for expensive nerve growth factors; potentially increasing control of stem cell differentiation with precise electrical stimulation; and creating a low maintenance, artificial framework for neural damage repairs. A key to making it all work is the graphene inkjet printing process developed in Claussen's research lab. This process takes advantage of graphene's wonder-material properties – it's a great conductor of electricity and heat, and is strong, stable and biocompatible – to produce low-cost, flexible and even wearable electronics. But there is a problem: once the graphene electronic circuits are printed, they have to be treated to improve their electrical conductivity. That usually means exposing them to high temperatures or chemicals, and either could damage flexible printing surfaces including plastic films or paper. Claussen and his research group solved the problem by replacing the high temperatures and chemicals with computer-controlled laser technology. This laser treatment removes ink binders and reduces graphene oxide to graphene – physically stitching together millions of tiny graphene flakes – improving the electrical conductivity more than a thousand times. This collaboration between Claussen's group of nanoengineers developing printed graphene technologies and Mallapragada's group of chemical engineers working on nerve regeneration began with some informal conversations on campus. That led to experimental attempts to grow stem cells on printed graphene and then to electrical stimulation experiments. "We knew this would be a really good platform for electrical stimulation," Das said. "But we didn't know it would differentiate these cells." But now that it has, the researchers say there are new possibilities to think about. The technology, for example, could one day be used to create dissolvable or absorbable nerve regeneration materials that could be surgically placed in a person's body and wouldn't require a second surgery to remove. This story is adapted from material from Iowa State University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.


News Article | April 20, 2017
Site: motherboard.vice.com

Apple said Wednesday it wants to stop mining the Earth entirely in pursuit of an iPhone made completely out of recyclable materials. "Can we one day stop mining the Earth altogether?," Apple asks at the top of its new Environmental Responsibility Report. It's a laudable goal, but it's currently just a platitude—no more meaningful than say, SpaceX hopes to eventually colonize Mars. If attempted in earnest, the world's largest company will surely spur innovation in mining practices and electronics recycling. But Apple has provided no roadmap of how it will begin to recycle many of the dozens of rare earth elements that scientists have thus far deemed impractical to recover. The goal of a mining-free iPhone is not only far off; at the moment, it's scientifically impossible. So, good idea, Apple. Now get to work. "It's a noble promise, and it sets a real 'stretch goal' for the company," Alex King, director of the Critical Materials Institute at the Department of Energy's Ames Laboratory, told me. Recycling aluminum is easy, but there is currently no strategy for how to recycle rare earth metals. "The current iPhone models use somewhere around 60 or 65 distinct chemical elements, most of which are not recycled at all today and only come from mines." Apple says it has created "risk profiles" for 44 elements within the iPhone and its other products, based on "environmental, social, and supply risk factors spanning the life of each material," and that it plans to "invest in research" for recycling rare Earth elements that science doesn't know how to yet. These are needed investments, but Apple has set no specific goals and has given itself no timeline other than "one day." "I don't see how they can possibly get the white color they want with 100 percent recycled material," Kyle Wiens, CEO of iFixit, which advocates for responsible recycling practices, told me. "So it's kind of an interesting goal from that perspective. It's 100 percent unattainable today, but it's a goal that lets them claim progress toward it without proving anything to the rest of us, because it's a metric that's independently unverifiable." Benjamin Sprecher, who is researching rare earth mineral recycling at the University of Leiden in the Netherlands, told me "there is no recycling infrastructure in place to produce some of these metals on the scale that Apple requires." Neodymium, for instance, which is used in the iPhone's speakers, has only been recycled in small quantities in proof-of-concept research studies at universities. "One needs to collect a large volume of waste electronics, and refine the recovered contaminated metals to the purity levels necessary for the electronics industry," Sprecher said. "This is usually more expensive than simply mining the metals." There's also no indication of where Apple would actually be able to source rare earth metals from: Recycling is not a one-to-one proposition and the vast majority of iPhones and MacBooks are not ultimately returned to Apple to be dismantled. "They will certainly not be able to make new iPhones just by recycling the materials in old iPhones," King said. "Their recycled materials will most likely come from other kinds of post-consumer scrap." Both researchers said Apple's goals will likely be possible sometime down the line, and both said that the company should be cheered for throwing its weight for trying to spur innovation in the recycling industry. At the same time, Apple artificially hampers the recycling of its own products, and has opposed right to repair legislation that would make it easier to extend the life of the products it makes today. "Technology is really complex; it is sophisticated to make it work, to ensure that you have security and privacy, [and] that somebody isn't giving you bad parts," Apple VP of Environment, Policy and Social Initiatives Lisa Jackson told VICE News about allowing independent repair of its products. So while it's definitely cool that Apple wants to reduce mining, it's certainly not doing everything it can to be green. "If Apple were sincere about the environment they would be helping their customers keep their expensive toys in service for a decade or longer in order to fully amortize the environmental costs of mining, manufacturing, and toxic damage to workers," Gay Gordon-Byrne, executive director of Repair.org, which is advocating for right to repair legislation, told me. "Everything else is putting lipstick on a pig."


Wysocki A.L.,University of Nebraska - Lincoln | Belashchenko K.D.,University of Nebraska - Lincoln | Antropov V.P.,Ames Laboratory
Nature Physics | Year: 2011

The discovery of superconductivity in LaFeAsO introduced ferropnictides as a new class of superconducting compounds with critical temperatures second only to those of the cuprates. Although the presence of iron makes the ferropnictides radically different from the cuprates, antiferromagnetism in the parent compounds suggests that superconductivity and magnetism are interrelated in both of them. However, the character of magnetic interactions and spin fluctuations in ferropnictides is not reasonably described by conventional models of magnetism. Here we show that the most puzzling features can be naturally reconciled within a rather simple effective spin model with a biquadratic interaction, which is consistent with electronic structure calculations. By going beyond the Heisenberg model, our description explains numerous experimental observations, including the peculiarities of the spin-wave spectrum, thin domain walls and crossover from a first- to second-order phase transition under doping. The model also offers insight into the occurrence of the nematic phase above the antiferromagnetic phase transition. © 2011 Macmillan Publishers Limited. All rights reserved.


King A.H.,Ames Laboratory
Scripta Materialia | Year: 2010

We assess the impact of triple lines in materials preparation and use by considering several examples of materials behavior in which they have identifiable effects. The microstructural roles of triple lines are also considered and some persistent scientific questions are raised. © 2010 Acta Materialia Inc.


Grant
Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase II | Award Amount: 741.62K | Year: 2011

Development of an energy harvesting system utilizing the magnetostrictive material, Galfenol, will be completed in this effort. The energy harvesting system will consist of Galfenol plates or sheets, magnetic circuit components, coupling structure, power conditioning electronics, sensor, and wireless transmitter. Lab testing and relevant environment testing through sea-trials will be completed on the system and compared to the predicted performance of FEA and analytical models. In addition, Galfenol wire fabrication efforts will be advanced with the primary goal of developing a Galfenol alloy and process capable of producing wire with the appropriate texture to maximize energy harvesting properties for future 1D devices.

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