Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Carbon dots dash toward 'green' recycling role

19.12.2016

Rice scientists, colleagues use doped graphene quantum dots to reduce carbon dioxide to fuel

Graphene quantum dots may offer a simple way to recycle waste carbon dioxide into valuable fuel rather than release it into the atmosphere or bury it underground, according to Rice University scientists.


A single nitrogen-doped graphene quantum dot with zig-zag edges.

Credit: Ajayan Group/Rice University

Nitrogen-doped graphene quantum dots (NGQDs) are an efficient electrocatalyst to make complex hydrocarbons from carbon dioxide, according to the research team led by Rice materials scientist Pulickel Ajayan. Using electrocatalysis, his lab has demonstrated the conversion of the greenhouse gas into small batches of ethylene and ethanol.

The research is detailed this week in Nature Communications.

Though they don't entirely understand the mechanism, the researchers found NGQDs worked nearly as efficiently as copper, which is also being tested as a catalyst to reduce carbon dioxide into liquid fuels and chemicals. And NGQDs keep their catalytic activity for a long time, they reported.

"It is surprising because people have tried all different kinds of catalysts. And there are only a few real choices such as copper," Ajayan said. "I think what we found is fundamentally interesting, because it provides an efficient pathway to screen new types of catalysts to convert carbon dioxide to higher-value products."

Those problems are hardly a secret. Atmospheric carbon dioxide rose above 400 parts per million earlier this year, the highest it's been in at least 800,000 years, as measured through ice-core analysis.

"If we can convert a sizable fraction of the carbon dioxide that is emitted, we could curb the rising levels of atmospheric carbon dioxide levels, which have been linked to climate change," said co-author Paul Kenis of the University of Illinois.

In lab tests, NGQDs proved able to reduce carbon dioxide by up to 90 percent and convert 45 percent into either ethylene or alcohol, comparable to copper electrocatalysts.

Graphene quantum dots are atom-thick sheets of carbon atoms that have been split into particles about a nanometer thick and just a few nanometers wide. The addition of nitrogen atoms to the dots enables varying chemical reactions when an electric current is applied and a feedstock like carbon dioxide is introduced.

"Carbon is typically not a catalyst," Ajayan said. "One of our questions is why this doping is so effective. When nitrogen is inserted into the hexagonal graphitic lattice, there are multiple positions it can take. Each of these positions, depending on where nitrogen sits, should have different catalytic activity. So it's been a puzzle, and though people have written a lot of papers in the last five to 10 years on doped and defective carbon being catalytic, the puzzle is not really solved."

"Our findings suggest that the pyridinic nitrogen (a basic organic compound) sitting at the edge of graphene quantum dots leads the catalytic conversion of carbon dioxide to hydrocarbons," said Rice postdoctoral researcher Jingjie Wu, co-lead author of the paper. "The next task is further increasing nitrogen concentration to help increase the yield of hydrocarbons."

Ajayan noted that while electrocatalysis is effective at lab scales for now, industry relies on scalable thermal catalysis to produce fuels and chemicals. "For that reason, companies probably won't use it any time soon for large-scale production. But electrocatalysis can be easily done in the lab, and we showed it will be useful in the development of new catalysts."

###

Co-lead authors of the paper are Sichao Ma of the University of Illinois at Urbana-Champaign and Kyushu University, Fukuoka, Japan, and Jing Sun of the Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences.

Co-authors are Jake Gold, Lingyang Zhu, Aaron Yu and Raymond Luo of the University of Illinois at Urbana-Champaign; Chandra Sekhar Tiwary of Rice; Byoungsu Kim of the University of Illinois at Urbana-Champaign and Kyushu University; Nitin Chopra and Ihab Odeh of SABIC Americas, Inc., Sugar Land, Texas; Robert Vajtai, a senior faculty fellow in materials science and nanoengineering at Rice; Jun Lou, a professor of materials science and nanoengineering at Rice; and Guqiao Ding of the Chinese Academy of Sciences. Kenis is the William H. and Janet G. Lycan Professor and head of chemical and biomolecular engineering at the University of Illinois at Urbana-Champaign with an appointment at Kyushu University.

Ajayan is chair of Rice's Department of Materials Science and NanoEngineering, the Benjamin M. and Mary Greenwood Anderson Professor in Engineering and a professor of chemistry.

SABIC Global Technologies, B.V. supported the research.

Read the abstract at http://www.nature.com/articles/ncomms13869

This news release can be found online at http://news.rice.edu/2016/12/16/carbon-dots-dash-toward-green-recycling-role/

Follow Rice News and Media Relations via Twitter @RiceUNews

Related materials:

Ajayan Research Group: http://ajayan.rice.edu

Rice Department of Materials Science and NanoEngineering: https://msne.rice.edu

Image for download:

http://news.rice.edu/files/2016/12/1219_CARBON-1-WEB-1tenn2c.jpg

Nitrogen-doped graphene quantum dots, like the ones in this transmission electron microscope image, proved adept at catalyzing carbon dioxide into complex hydrocarbons, according to Rice University scientists. (Credit: Ajayan Group/Rice University)

http://news.rice.edu/files/2016/12/1219_CARBON-2-WEB-1zx973u.jpg

A single nitrogen-doped graphene quantum dot with zig-zag edges. (Credit: Ajayan Group/Rice University)

http://news.rice.edu/files/2016/12/1219_CARBON-3-WEB-25470cf.jpg

Nitrogen-doped graphene quantum dots stand out from a substrate in a transmission electron microscope image. The dots are effective electrocatalysts that can reduce carbon dioxide, a greenhouse gas, to valuable hydrocarbons like ethylene and ethanol. (Credit: Ajayan Group/Rice University)

http://news.rice.edu/files/2016/12/1219_CARBON-4-WEB-2czloeq.jpg

An illustration of a nitrogen-doped graphene quantum dot like those being tested at Rice University for use as catalysts to reduce carbon dioxide, a greenhouse gas, into valuable hydrocarbons. (Credit: Ajayan Group/Rice 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 happiest students 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/RiceUniversityoverview.

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

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

http://news.rice.edu 

David Ruth | EurekAlert!

More articles from Materials Sciences:

nachricht Watching atoms move in hybrid perovskite crystals reveals clues to improving solar cells
22.11.2017 | University of California - San Diego

nachricht Fine felted nanotubes: CAU research team develops new composite material made of carbon nanotubes
22.11.2017 | Christian-Albrechts-Universität zu Kiel

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Nanoparticles help with malaria diagnosis – new rapid test in development

The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.

Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

UCLA engineers use deep learning to reconstruct holograms and improve optical microscopy

22.11.2017 | Medical Engineering

Watching atoms move in hybrid perovskite crystals reveals clues to improving solar cells

22.11.2017 | Materials Sciences

New study points the way to therapy for rare cancer that targets the young

22.11.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>