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Author Skaltsas, T.; Ke, X.; Bittencourt, C.; Tagmatarchis, N. doi  openurl
  Title Ultrasonication induces oxygenated species and defects onto exfoliated graphene Type A1 Journal article
  Year (down) 2013 Publication The journal of physical chemistry: C : nanomaterials and interfaces Abbreviated Journal J Phys Chem C  
  Volume 117 Issue 44 Pages 23272-23278  
  Keywords A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)  
  Abstract The effect of ultrasonication parameters, such as time and power applied, to exfoliate graphite in o-dichlorobenzene (o-DCB) and N-methyl-1,2-pyrrolidone (NMP) was examined. It was found that the concentration of graphene was higher in o-DCB, while its dispersibility was increased when sonication was applied for a longer period and/or at higher power. However, spectroscopic examination by X-ray photoelectron spectroscopy (XPS) revealed that ultrasonication causes defects and induces oxygen functional groups in the form of carboxylic acids and ethers/epoxides onto the graphene lattice. Additional proof for the latter arose from Raman, IR, and thermogravimetry studies. The carboxylic acids and ethers/epoxides onto exfoliated graphene were derived from air during ultrasonication and found independent of the solvent used for the exfoliation and the power and/or time ultrasonication applied. Quantitative evaluation of the amount of oxygenated species present on exfoliated graphene as performed by high-resolution XPS revealed that the relative oxygen percentage was higher when exfoliation was performed in NMP. Finally, the sonication time and/or power affected the oxygen content on exfoliated graphene, since extended ultrasonication resulted in a decrease in the oxygen content on exfoliated graphene, with a simultaneous increase of defected sp(3) carbon atoms.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Washington, D.C. Editor  
  Language Wos 000326845400090 Publication Date 2013-10-03  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1932-7447;1932-7455; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 4.536 Times cited 65 Open Access  
  Notes Approved Most recent IF: 4.536; 2013 IF: 4.835  
  Call Number UA @ lucian @ c:irua:112710 Serial 3797  
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Author Bittencourt, C.; Ke, X.; Van Tendeloo, G.; Tagmatarchis, N.; Guttmann, P. pdf  doi
openurl 
  Title NEXAFS spectromicroscopy of suspended carbon nanohorns Type A1 Journal article
  Year (down) 2013 Publication Chemical physics letters Abbreviated Journal Chem Phys Lett  
  Volume 587 Issue Pages 85-87  
  Keywords A1 Journal article; Electron microscopy for materials research (EMAT)  
  Abstract We demonstrate that near-edge X-ray-absorption fine-structure spectroscopy combined with full-field transmission X-ray microscopy can be used to study the electronic structure of suspended carbon nanohorns. Based on reports of electronic structure calculations additional spectral features observed in the π region of the NEXAFS spectrum recorded on the carbon nanohorns were associated to the presence of the pentagonal rings and the folding of the graphene sheet.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Amsterdam Editor  
  Language Wos 000326104500016 Publication Date 2013-09-18  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0009-2614; ISBN Additional Links UA library record; WoS full record; WoS citing articles  
  Impact Factor 1.815 Times cited 4 Open Access  
  Notes Fp7; Countatoms; Approved Most recent IF: 1.815; 2013 IF: 1.991  
  Call Number UA @ lucian @ c:irua:111592 Serial 2339  
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