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0885-A09-34.1

Evolved Gas Analysis of Heat-Treated Carbon Nanomaterials Yury M.Shulga1, Vyacheslav M.Martynenko1, R.O.Loutfy2, and Alex P.Moravsky2 1 Institute of Problems of Chemical Physics RAS, Chernogolovka, Moscow region, 142432 Russia 2 MER Corporation, Tucson, AZ 85706, USA ABSTRACT Gases evolved on heat-treatment of intact fullerite C60, single-walled (SW) and multiwalled nanotubes (MWNTs) and chemically modified carbon nanomaterials (deuterofullerites C60Dx, hydrogenated SWNTs and fluorinated MWNTs) are studied by mass spectrometry. INTODUCTION Physical and chemical sorption of small molecules by high specific surface area carbon nanomaterials readily occurs during their synthesis, purification and storage. Trapped molecules can affect material properties. For example, gas desorption from carbon nanotube field emitters leads to inferior performance and shorter lifetime of vacuum electronic tubes. Adsorbates on carbon nanomaterials can reduce the capacity of hydrogen storage devices. Therefore, the gas composition and quantity evolved by carbon nanostructures at elevated temperatures merits critical evaluation. The paper presents data on evolved gas composition, which occurred upon heat treatment of fullerites, single-walled and multi-walled nanotubes. Variation of sorption properties upon chemical modification of nanostructures is discussed.

EXPERIMENTAL DETAILS Gases evolved from the specimens under elevated temperature were analyzed with 70 eV electron impact mass-spectrometer MI-1201B (Sumy, USSR). The quartz ampoule equipped with adjustable heater was loaded with a few mg of a specimen and connected to the massspectrometer inlet. The sample was evacuated to 2×10-5 Pa for one day at room temperature to remove weakly bound impurities and then heated at temperature T1 for 3 hours and analyzed. Evacuation, heating at T1