New Graphene-Based Material Clarifies Graphite Oxide Chemistry

Tag : 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 an isotopicallylabeled material from measurements by co-author Frank Stadermann ofWashington University in St Louis. Stadermann used a special massspectrometer typically used for measuring the isotope abundances ofvarious elements that are in micrometeorites that have landed onEarth. Then, 100 percent carbon-13 labeled graphite was convertedto 100 percent carbon-13 labeled graphite oxide, also a layeredmaterial but with some oxygen atoms attached to the graphene bychemical 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 (Departments 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.

Co-authors on the Science article include: Weiwei Cai, RichardPiner, Sungjin Park, Dongxing Yang, Aruna Velamakanni, MerylStoller and Jinho An (all of the Ruoff research group at TheUniversity of Texas at Austin); Sung Jin An, formerly of PohangUniversity of Science and Technology (POSTECH-Korea) and a visitinggraduate student in the Ruoff group during the study; Dongmin Chen(Beijing National Laboratory for Condensed Matter Physics,Institute of Physics, Chinese Academy of Sciences); Stadermann; andIshii and Shaibat of the University of Illinois-Chicago.
Rod Ruoff | Source: EurekAlert!
Further information: www.utexas.edu