Rice University scientists have achieved a pivotal breakthrough in the development of a cable that will make an efficient electric grid of the future possible.
Armchair quantum wire (AQW) will be a weave of metallic nanotubes that can carry electricity with negligible loss over long distances. It will be an ideal replacement for the nation's copper-based grid, which leaks electricity at an estimated 5 percent per 100 miles of transmission, said Rice chemist Andrew R. Barron, author of a paper about the latest step forward published online by the American Chemical Society journal Nano Letters.
A prime technical hurdle in the development of this "miracle cable," Barron said, is the manufacture of massive amounts of metallic single-walled carbon nanotubes, dubbed armchairs for their unique shape. Armchairs are best for carrying current, but can't yet be made alone. They grow in batches with other kinds of nanotubes and have to be separated out, which is a difficult process given that a human hair is 50,000 times larger than a single nanotube.
Barron's lab demonstrated a way to take small batches of individual nanotubes and make them dramatically longer. Ideally, long armchair nanotubes could be cut, re-seeded with catalyst and re-grown indefinitely.
The paper was written by graduate student and first author Alvin Orbaek, undergraduate student Andrew Owens and Barron, the Charles W. Duncan Jr.-Welch Professor of Chemistry and a professor of materials science.
Amplification of nanotubes was seen as a key step toward the practical manufacture of AQW by the late Rice professor, nanotechnology pioneer and Nobel laureate Richard Smalley, who worked closely with Barron and Rice chemist James Tour, the T.T. and W.F. Chao Chair in Chemistry as well as a professor of mechanical engineering and materials science and of computer science, to lay out a path for its development.
Barron charged Orbaek with the task of following through when he joined the lab five years ago. "When I first heard about Rice University, it was because of Rick Smalley and carbon nanotubes," said Orbaek, a native of Ireland. "He had a large global presence with regard to nanotechnology, and that reached me.
"So I was delighted to come here and find I'd be working on nanotube growth that was related to Smalley's work."
Orbaek said he hasn't strayed far from Barron's original direction, which involved chemically attaching an iron/cobalt catalyst to the ends of nanotubes and then fine-tuning the temperature and environment in which amplification could occur.
"My group, with Smalley and Tour's group, demonstrated you could do this -- but in the first demonstration, we got only one tube to grow out of hundreds or thousands," Barron said. Subsequent experiments raised the yield, but tube growth was minimal. In other attempts, the catalyst would literally eat -- or "etch" -- the nanotubes, he said.
Refining the process has taken years, but the payoff is clear because up to 90 percent of the nanotubes in a batch can now be amplified to significant lengths, Barron said. The latest experiments focused on single-walled carbon nanotubes of various chiralities, but the researchers feel the results would be as great, and probably even better, with a batch of pristine armchairs.
The key was finding the right balance of temperatures, pressures, reaction times and catalyst ratios to promote growth and retard etching, Barron said. While initial growth took place at 1,000 degrees Celsius, the researchers found the amplification step required lowering the temperature by 200 degrees, in addition to adjusting the chemistry to maximize the yield.
"What we're getting to is that sweet spot where most of the nanotubes grow and none of them etch," Barron said.
Wade Adams, director of Rice's Richard E. Smalley Institute for Nanoscale Science and Technology and principal investigator on the AQW project, compared the technique to making sourdough bread. "You make a little batch of pure metallics and then amplify that tremendously to make a large amount. This is an important increment in developing the science to make AQW.
Adams noted eight Rice professors and dozens of their students are working on aspects of AQW. "We know how to spin nanotubes into fibers, and their properties are improving rapidly too," he said. "All this now has to come together in a grand program to turn quantum wires into a product that will carry vast amounts of electricity around the world."
Barron and his team are continuing to fine-tune their process and hope that by summer's end they can begin amplifying armchair nanotubes with the goal of making large quantities of pure metallics. "We're always learning more about the mechanisms by which nanotubes grow," said Orbaek, who sees the end game as the development of a single furnace to grow nanotubes from scratch, cap them with new catalyst, amplify them and put out a steady stream of fiber for cables.
"What we've done is a baby step," he said. "But it verifies that, in the big picture, armchair quantum wire is technically feasible."
Orbaek said he is thrilled to play a role in achieving amplification, which Smalley recognized as necessary to his dream of an efficient energy grid that would catalyze solutions to many of the world's problems.
"I'd love to meet him now to say, 'Hey, man, you were right,'" he said.
The Robert A. Welch Foundation and the Air Force Office of Scientific Research funded the research. The Air Force Research Laboratory is primary funding agency for the AQW project.
Read the abstract at http://pubs.acs.org/doi/abs/10.1021/nl201315j
Download high-resolution images here:http://www.media.rice.edu/images/media/NEWSRELS/0712_AQW_montage1.jpg
(Credit: Barron Lab/Rice University)
(researchers)Rice University graduate student Alvin Orbaek, left, and Professor Andrew Barron developed a method to extend the length of carbon nanotubes.
(Credit: Jeff Fitlow/Rice University)
Located on a 285-acre forested campus in Houston, Texas, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is known for its "unconventional wisdom." With 3,485 undergraduates and 2,275 graduate students, Rice's undergraduate student-to-faculty ratio is less than 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 4 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://futureowls.rice.edu/images/futureowls/Rice_Brag_Sheet.pdf.
David Ruth | EurekAlert!
Plant inspiration could lead to flexible electronics
22.06.2017 | American Chemical Society
A rhodium-based catalyst for making organosilicon using less precious metal
22.06.2017 | Tokyo Institute of Technology
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.
New Manufacturing Technologies for New Products
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
22.06.2017 | Life Sciences
22.06.2017 | Materials Sciences
22.06.2017 | Materials Sciences