Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Study shows availability of hydrogen controls chemical structure of graphene oxide: Metastable material

Georgia Tech researchers Angelo Bongiorno and Elisa Riedo pose with a graphene oxide sample, with a computer model of the materialís structure shown behind them.

Credit: Georgia Tech Photo: Gary Meek
Georgia Tech researchers Angelo Bongiorno and Elisa Riedo pose with a graphene oxide sample, with a computer model of the materialís structure shown behind them.

Credit: Georgia Tech Photo: Gary Meek

Abstract:
A new study shows that the availability of hydrogen plays a significant role in determining the chemical and structural makeup of graphene oxide, a material that has potential uses in nano-electronics, nano-electromechanical systems, sensing, composites, optics, catalysis and energy storage.

Study shows availability of hydrogen controls chemical structure of graphene oxide: Metastable material

Atlanta, GA | Posted on May 22nd, 2012

The study also found that after the material is produced, its structural and chemical properties continue to evolve for more than a month as a result of continuing chemical reactions with hydrogen.

Understanding the properties of graphene oxide - and how to control them - is important to realizing potential applications for the material. To make it useful for nano-electronics, for instance, researchers must induce both an electronic band gap and structural order in the material. Controlling the amount of hydrogen in graphene oxide may be the key to manipulating the material properties.

"Graphene oxide is a very interesting material because its mechanical, optical and electronic properties can be controlled using thermal or chemical treatments to alter its structure," said Elisa Riedo, an associate professor in the School of Physics at the Georgia Institute of Technology. "But before we can get the properties we want, we need to understand the factors that control the material's structure. This study provides information about the role of hydrogen in the reduction of graphene oxide at room temperature."

The research, which studied graphene oxide produced from epitaxial graphene, was reported on May 6 in the journal Nature Materials. The research was sponsored by the National Science Foundation, the Materials Research Science and Engineering Center (MRSEC) at Georgia Tech, and by the U.S. Department of Energy.

Graphene oxide is formed through the use of chemical and thermal processes that mainly add two oxygen-containing functional groups to the lattice of carbon atoms that make up graphene: epoxide and hydroxyl species. The Georgia Tech researchers began their studies with multilayer expitaxial graphene grown atop a silicon carbide wafer, a technique pioneered by Walt de Heer and his research group at Georgia Tech. Their samples included an average of ten layers of graphene.

After oxidizing the thin films of graphene using the established Hummers method, the researchers examined their samples using X-ray photo-emission spectroscopy (XPS). Over about 35 days, they noticed the number of epoxide functional groups declining while the number of hydroxyl groups increased slightly. After about three months, the ratio of the two groups finally reached equilibrium.

"We found that the material changed by itself at room temperature without any external stimulation," said Suenne Kim, a postdoctoral fellow in Riedo's laboratory. "The degree to which it was unstable at room temperature was surprising."

Curious about what might be causing the changes, Riedo and Kim took their measurements to Angelo Bongiorno, an assistant professor who studies computational materials chemistry in Georgia Tech's School of Chemistry and Biochemistry. Bongiorno and graduate student Si Zhou studied the changes using density functional theory, which suggested that hydrogen could be combining with oxygen in the functional groups to form water. That would favor a reduction in the epoxide groups, which is what Riedo and Kim were seeing experimentally.

"Elisa's group was doing experimental measurements, while we were doing theoretical calculations," Bongiorno said. "We combined our information to come up with the idea that maybe there was hydrogen involved."

The suspicions were confirmed experimentally, both by the Georgia Tech group and by a research team at the University of Texas at Dallas. This information about the role of hydrogen in determining the structure of graphene oxide suggests a new way to control its properties, Bongiorno noted.

"During synthesis of the material, we could potentially use this as a tool to change the structure," he said. "By understanding how to use hydrogen, we could add it or take it out, allowing us to adjust the relative distribution and concentration of the epoxide and hydroxyl species which control the properties of the material."

Riedo and Bongiorno acknowledge that their material - based on epitaxial graphene - may be different from the oxide produced from exfoliated graphene. Producing graphene oxide from flakes of the material involves additional processing, including dissolving in an aqueous solution and then filtering and depositing the material onto a substrate. But they believe hydrogen plays a similar role in determining the properties of exfoliated graphene oxide.

"We probably have a new new form of graphene oxide, one that may be more useful commercially, although the same processes should also be happening within the other form of graphene oxide," said Bongiorno.

The next steps are to understand how to control the amount of hydrogen in epitaxial graphene oxide, and what conditions may be necessary to affect reactions with the two functional groups. Ultimately, that may provide a way to open an electronic band gap and simultaneously obtain a graphene-based material with electron transport characteristics comparable to those of pristine graphene.

"By controlling the properties of graphene oxide through this chemical and thermal reduction, we may arrive at a material that remains close enough to graphene in structure to maintain the order necessary for the excellent electronic properties, while having the band gap needed to create transistors," Riedo said. "It could be that graphene oxide is the way to arrive at that type of material."

Beyond those already mentioned, the paper's authors included Yike Hu, Claire Berger and Walt de Heer from the School of Physics at Georgia Tech, and Muge Acik and Yves Chabal from the Department of Materials Science and Engineering at the University of Texas at Dallas.

This research was supported by the National Science Foundation under grants CMMI-1100290, DMR-0820382 and DMR-0706031, and by the U.S. Department of Energy's Office of Basic Energy Sciences under grants DE-FG02-06ER46293 and DE-SC001951. The content is solely the responsibility of the principal investigators and does not necessarily represent the official views of the National Science Foundation or the Department of Energy.

####

For more information, please click here

Contacts:
John Toon

404-894-6986

Copyright © Georgia Institute of Technology Research News

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Rice University boots up powerful microscopes: New electron microscopes will capture images at subnanometer resolution June 29th, 2015

The Hydrogen-Fuel cell will revolutionize the economy of the world: New non-platinum and nanosized catalyst for polymer electrolyte fuel cell June 29th, 2015

June 29th, 2015

Efforts to Use Smart Nanocarriers to Cure Leukemia Yield Promising Results June 29th, 2015

Chemistry

The Hydrogen-Fuel cell will revolutionize the economy of the world: New non-platinum and nanosized catalyst for polymer electrolyte fuel cell June 29th, 2015

X-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th, 2015

Green Chemistry Methods Used in Iran to Produce Zinc Oxide Nanoparticles June 27th, 2015

Graphene

Angstron Materials Appoints VP for Business Development And Engineering June 27th, 2015

Spain nanotechnology featured at NANO KOREA 2015 June 26th, 2015

Breakthrough graphene production could trigger revolution in artificial skin development June 25th, 2015

NEMS

Weighing -- and imaging -- molecules one at a time April 28th, 2015

Scientists join forces to reveal the mass and shape of single molecules April 27th, 2015

Surface matters: Huge reduction of heat conduction observed in flat silicon channels April 23rd, 2015

Iranian Scientists Evaluate Dynamic Interaction between 2 Carbon Nanotubes April 14th, 2015

Govt.-Legislation/Regulation/Funding/Policy

X-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th, 2015

Graphene breakthrough as Bosch creates magnetic sensor 100 times more sensitive than silicon equivalent June 28th, 2015

The peaks and valleys of silicon: Team of USC Viterbi School of Engineering Researchers introduce new layered semiconducting materials as silicon alternative June 27th, 2015

Building a better semiconductor: Research led by Michigan State University could someday lead to the development of new and improved semiconductors June 27th, 2015

Chip Technology

Making new materials with micro-explosions: ANU media release: Scientists have made exotic new materials by creating laser-induced micro-explosions in silicon, the common computer chip material June 29th, 2015

The peaks and valleys of silicon: Team of USC Viterbi School of Engineering Researchers introduce new layered semiconducting materials as silicon alternative June 27th, 2015

Building a better semiconductor: Research led by Michigan State University could someday lead to the development of new and improved semiconductors June 27th, 2015

Opening a new route to photonics Berkeley lab researchers find way to control light in densely packed nanowaveguides June 27th, 2015

Sensors

Graphene breakthrough as Bosch creates magnetic sensor 100 times more sensitive than silicon equivalent June 28th, 2015

The peaks and valleys of silicon: Team of USC Viterbi School of Engineering Researchers introduce new layered semiconducting materials as silicon alternative June 27th, 2015

Green Chemistry Methods Used in Iran to Produce Zinc Oxide Nanoparticles June 27th, 2015

Towards graphene biosensors June 24th, 2015

Nanoelectronics

Exagan Raises Ä5.7 Million to Produce High-efficiency GaN-on-Silicon Power-switching Devices on 200mm Wafers: Leti-and-Soitec Spinout Focused on Becoming Leading European Source Of GaN Devices for Solar, Automotive, Telecoms and Infrastructure June 25th, 2015

Nanowires could be the LEDs of the future June 25th, 2015

Leti to Present Solutions to New Applications Using 3D Technologies at SEMICON West LetiDay Event, July 14: Leti Experts also Will Speak at TechXPOT Session on MEMS and STS Session on Lithography Cost-and-Productivity Issues Below 14nm June 22nd, 2015

Graphene heat-transfer riddle unraveled June 17th, 2015

Discoveries

The Hydrogen-Fuel cell will revolutionize the economy of the world: New non-platinum and nanosized catalyst for polymer electrolyte fuel cell June 29th, 2015

June 29th, 2015

Efforts to Use Smart Nanocarriers to Cure Leukemia Yield Promising Results June 29th, 2015

Making new materials with micro-explosions: ANU media release: Scientists have made exotic new materials by creating laser-induced micro-explosions in silicon, the common computer chip material June 29th, 2015

Materials/Metamaterials

Green Chemistry Methods Used in Iran to Produce Zinc Oxide Nanoparticles June 27th, 2015

Spain nanotechnology featured at NANO KOREA 2015 June 26th, 2015

Dais Analytic Unveils New Version of Aqualyte Membrane Technology: Updates to the Basis of the Company's Industry-Changing Nanotechnology Designed to Strengthen Position in Global Air, Energy, and Water Markets June 26th, 2015

Iranian Researchers Synthesize Nanostructures with Controlled Shape, Structure June 25th, 2015

Announcements

The Hydrogen-Fuel cell will revolutionize the economy of the world: New non-platinum and nanosized catalyst for polymer electrolyte fuel cell June 29th, 2015

June 29th, 2015

Efforts to Use Smart Nanocarriers to Cure Leukemia Yield Promising Results June 29th, 2015

Making new materials with micro-explosions: ANU media release: Scientists have made exotic new materials by creating laser-induced micro-explosions in silicon, the common computer chip material June 29th, 2015

Energy

The Hydrogen-Fuel cell will revolutionize the economy of the world: New non-platinum and nanosized catalyst for polymer electrolyte fuel cell June 29th, 2015

June 29th, 2015

Making new materials with micro-explosions: ANU media release: Scientists have made exotic new materials by creating laser-induced micro-explosions in silicon, the common computer chip material June 29th, 2015

X-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th, 2015

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

June 29th, 2015

X-rays and electrons join forces to map catalytic reactions in real-time: New technique combines electron microscopy and synchrotron X-rays to track chemical reactions under real operating conditions June 29th, 2015

Green Chemistry Methods Used in Iran to Produce Zinc Oxide Nanoparticles June 27th, 2015

Spain nanotechnology featured at NANO KOREA 2015 June 26th, 2015

Photonics/Optics/Lasers

Making new materials with micro-explosions: ANU media release: Scientists have made exotic new materials by creating laser-induced micro-explosions in silicon, the common computer chip material June 29th, 2015

Opening a new route to photonics Berkeley lab researchers find way to control light in densely packed nanowaveguides June 27th, 2015

The quantum spin Hall effect is a fundamental property of light June 25th, 2015

Laser spectroscopy: A novel microscope for nanosystems June 25th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project