Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Microwaved nanotubes come up clean

25.01.2016

Rice, Swansea scientists use household oven to help decontaminate carbon nanotubes

Amid all the fancy equipment found in a typical nanomaterials lab, one of the most useful may turn out to be the humble microwave oven.


Treatment with a microwave oven and chlorine removes stubborn iron catalyst residues from carbon nanotubes, according to researchers at Rice University and Swansea University. The two-step process may make them more suitable for sensitive applications.

Credit: Virginia Goméz Jiménez/Swansea University

A standard kitchen microwave proved effective as part of a two-step process invented at Rice and Swansea universities to clean carbon nanotubes.

Basic nanotubes are good for many things, like forming into microelectronic components or electrically conductive fibers and composites; for more sensitive uses like drug delivery and solar panels, they need to be as pristine as possible.

Nanotubes form from metal catalysts in the presence of heated gas, but residues of those catalysts (usually iron) sometimes remain stuck on and inside the tubes. The catalyst remnants can be difficult to remove by physical or chemical means because the same carbon-laden gas used to make the tubes lets carbon atoms form encapsulating layers around the remaining iron, reducing the ability to remove it during purification.

In the new process, treating the tubes in open air in a microwave burns off the amorphous carbon. The nanotubes can then be treated with high-temperature chlorine to eliminate almost all of the extraneous particles.

The process was revealed today in the Royal Society of Chemistry journal RSC Advances.

The labs of chemists Robert Hauge, Andrew Barron and Charles Dunnill led the study. Barron is a professor at Rice in Houston and at Swansea University in the United Kingdom. Rice's Hauge is a pioneer in nanotube growth techniques. Dunnill is a senior lecturer at the Energy Safety Research Institute at Swansea.

There are many ways to purify nanotubes, but at a cost, Barron said. "The chlorine method developed by Hauge has the advantage of not damaging the nanotubes, unlike other methods," he said. "Unfortunately, many of the residual catalyst particles are surrounded by a carbon layer that stops the chlorine from reacting, and this is a problem for making high-purity carbon nanotubes."

The researchers gathered microscope images and spectroscopy data on batches of single-walled and multiwalled nanotubes before and after microwaving them in a 1,000-watt oven, and again after bathing them in an oxidizing bath of chlorine gas under high heat and pressure. They found that once the iron particles were exposed to the microwave, it was much easier to get them to react with chlorine. The resulting volatile iron chloride was then removed.

Eliminating iron particles lodged inside large multiwalled nanotubes proved to be harder, but transmission electron microscope images showed their numbers, especially in single-walled tubes, to be greatly diminished.

"We would like to remove all the iron, but for many applications, residue within these tubes is less of an issue than if it were on the surface," Barron said. "The presence of residual catalyst on the surface of carbon nanotubes can limit their use in biological or medical applications."

Co-authors of the study are Virginia Gomez, postdoctoral research assistant at Swansea; Silvia Irusta, a professor at the University of Zaragoza, Spain; and Wade Adams, a senior faculty fellow in materials science and nanoengineering at Rice.

Hauge is a distinguished faculty fellow in chemistry and in materials science and nanoengineering at Rice. Barron is the Charles W. Duncan Jr.-Welch Professor of Chemistry and a professor of materials science and nanoengineering at Rice and the Sêr Cymru Chair of Low Carbon Energy and Environment at Swansea.

###

David Ruth
713-348-6327
david@rice.edu

Mike Williams
713-348-6728
mikewilliams@rice.edu

The Robert A. Welch Foundation and the Welsh Government Sêr Cymru Program supported the research.

Read the abstract at http://pubs.rsc.org/en/content/articlelanding/2016/ra/c5ra24854j#!divAbstract

This news release can be found online at http://news.rice.edu/2016/01/22/microwaved-nanotubes-come-up-clean/

Follow Rice News and Media Relations via Twitter @RiceUNews

Related Materials:

Barron Research Group: http://barron.rice.edu/Barron.html

Dunnill bio: http://www.swansea.ac.uk/staff/academic/engineering/dunnillcharlie/

Wiess School of Natural Sciences: http://naturalsciences.rice.edu

Images for download:

http://news.rice.edu/wp-content/uploads/2016/01/0118_CLEAN-1-WEB.jpg

Treatment with a microwave oven and chlorine removes stubborn iron catalyst residues from carbon nanotubes, according to researchers at Rice University and Swansea University. The two-step process may make them more suitable for sensitive applications. (Credit: Virginia Goméz Jiménez/Swansea University)

http://news.rice.edu/wp-content/uploads/2016/01/0118_CLEAN-2-WEB.jpg

Multiwalled nanotubes before treatment with a Rice University/Swansea University process to remove catalyst residue from their surfaces and from inside. The process begins with heating the nanotubes in a standard kitchen microwave oven. (Credit: Virginia Goméz Jiménez/Swansea University)

'

http://news.rice.edu/wp-content/uploads/2016/01/0118_CLEAN-3-WEB.jpg

A multiwalled carbon nanotube cleaned with a process developed at Rice University and Swansea University shows iron catalyst residue has been removed from the surface, while most particles have been removed from inside the nanotube's walls. The process is expected to make nanotubes more suitable for applications like drug delivery and solar panels. (Credit: Virginia Goméz Jiménez/Swansea University)

Located on a 300-acre forested campus in Houston, 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 home to the Baker Institute for Public Policy. With 3,910 undergraduates and 2,809 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for best quality of life and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/AboutRiceUniversity.

Media Contact

David Ruth
david@rice.edu
713-348-6327

 @RiceUNews

http://news.rice.edu 

David Ruth | EurekAlert!

More articles from Materials Sciences:

nachricht Reliable molecular toggle switch developed
30.03.2017 | Karlsruher Institut für Technologie (KIT)

nachricht Researchers shoot for success with simulations of laser pulse-material interactions
29.03.2017 | DOE/Oak Ridge National Laboratory

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Challenging European Research Project to Develop New Tiny Microscopes

The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.

To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

'On-off switch' brings researchers a step closer to potential HIV vaccine

30.03.2017 | Health and Medicine

Penn studies find promise for innovations in liquid biopsies

30.03.2017 | Health and Medicine

An LED-based device for imaging radiation induced skin damage

30.03.2017 | Medical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>