New Graphene-Based Material Help Solve Structure of Graphite Oxide

Tag : graphite

To get an idea of the nanomaterial graphene, imagine a lightweightmaterial having the strongest chemical bond in nature and, thus,exceptional mechanical properties. In addition it conducts heatbetter than any other material and has charge carriers movingthrough it at a significant fraction of the speed of light. Just anatom thick, graphene consists of a "chickenwire" (orhoneycomb) bonding arrangement of carbon atoms – also knownas a single layer of graphite.
Mechanical Engineering Professor Rod Ruoff and his co-authors have,for the first time, prepared carbon-13 labeled graphite. They didthis by first making graphite that had every "normal"carbon atom having the isotope carbon-12, which is magneticallyinactive, replaced with carbon-13, which is magnetically active.They then converted that to carbon-13 labeled graphite oxide andused solid-state nuclear magnetic resonance to discern the detailedchemical structure of graphite oxide.
The work by Ruoff's team will appear in the Sept. 26 issue of thejournal Science.
"As a result of our work published in Science, it will now bepossible for scientists and engineers to create different types ofgraphene (by using carbon-13 labeled graphene as the startingmaterial and doing further chemistry to it) and to study suchgraphene-based materials with solid-state nuclear magneticresonance to obtain their detailed chemical structure," Ruoffsays. "This includes situations such as where the graphene ismixed with a polymer and chemically bonded at critical locations tomake remarkable polymer matrix composites; or embedded in glass orceramic materials; or used in nanoelectronic components; or mixedwith an electrolyte to provide superior supercapacitor or batteryperformance. If we don't know the chemistry in detail, we won't beable to optimize properties."
Graphene-based materials are a focus area of research at theuniversity because they are expected to have applications forultra-strong yet lightweight materials that could be used inautomobiles and airplanes to improve fuel efficiency, the blades ofwind turbines for improved generation of electrical power, ascritical components in nanoelectronics that could have blazingspeeds but very low power consumption, for electrical energystorage in batteries and supercapacitors to enable renewable energyproduction at a large scale and in transparent conductive filmsthat will be used in solar cells and image display technology. Inalmost every application, sensitive chemical interactions withsurrounding materials will play a central role in understanding andoptimizing performance.
Ruoff and his team proved they had made such anisotopically-labeled material from measurements by co-author FrankStadermann of Washington University in St Louis. Stadermann used aspecial mass spectrometer typically used for measuring the isotopeabundances of various elements that are in micrometeorites thathave landed on Earth. Then, 100 percent carbon-13 labeled graphitewas converted to 100 percent carbon-13 labeled graphite oxide, alsoa layered material but with some oxygen atoms attached to thegraphene by chemical bonds.
Co-authors Yoshitaka Ishii and Medhat Shaibat of the University ofIllinois-Chicago then used solid state nuclear magnetic resonanceto help reveal the detailed chemical bonding network in graphiteoxide. Ruoff says even though graphite oxide was first synthesizedmore than150 years ago the distribution of oxygen atoms has beendebated even quite recently.
"The ability to control the isotopic labeling betweencarbon-12 and carbon-13 will lead to many other sorts ofstudies," says Ruoff, who holds the Cockrell Family RegentsChair in Engineering #7.
He collaborates on other graphene projects with other universityscientists and engineers such as Allan MacDonald (Department ofPhysics and Astronomy), Sanjay Banerjee, Emanuel Tutuc and BhagawanSahu (Department of Electrical and Computer Engineering) and GyeongHwang (Department of Chemical Engineering), and some of thesecollaborations include industrial partners such as TexasInstruments, IBM and others.
P osted September 26th, 2008