Deoxygenation of Graphene Oxide: Reduction or Cleaning?
journal contributionposted on 16.12.2015, 23:35 by Helen R. Thomas, Stephen P. Day, William E. Woodruff, Cristina Vallés, Robert J. Young, Ian A. Kinloch, Gavin W. Morley, John V. Hanna, Neil R. Wilson, Jonathan P. Rourke
We show that the two-component model of graphene oxide (GO), that is, composed of highly oxidized carbonaceous debris complexed to oxygen functionalized graphene sheets, is a generic feature of the synthesis of GO, independent of oxidant or protocol used. The debris present, roughly one-third by mass, can be removed by a base wash. A number of techniques, including solid state NMR, demonstrate that the properties of the base-washed material are independent of the base used and that it contains similar functional groups to those present in the debris but at a lower concentration. Removal of the oxidation debris cleans the GO, revealing its true monolayer nature and in the process increases the C/O ratio (i.e., a deoxygenation). By contrast, treating GO with hydrazine both removes the debris and reduces (both deoxygenations) the graphene sheets.