Initial stages of graphene oxide cracking in basic media

New insights into oxygen surface coverage and the resulting two-component structure of graphene oxide

“…The controlled action of permanganate anions is the key step here [35,67,79] but heretofore its essential details have been elusive. In particular, it is contrary to detailed and voluminous experimental evidence to assume that oxygen transfer occurs on defect-free basal plane [80,81], either curved [35,[82][83][84] or flat [4,83,85,86]; indeed, the putative decoration of these new unzipped edges with quinone or phenol oxygen functionalities [39,[87][88][89][90][91] implies that the desorption (TG-MS) spectrum would be dominated by high-temperature evolution of CO [92][93][94], which is clearly not the case (see Figure 3). Furthermore, this is contrary to the observation [4] that the "conversion … to an oxidized form of graphite [occurs by virtue of] an edge-to-centre propagation of oxygen functionalities" [95].…”

“…Indeed, sonication treatments were used before a general procedure was adopted for identifying and quantifying the bwGO and OD [20,33]. There is no doubt that the essential details of the structure of GO remain a challenging topic and a satisfactory structural and compositional model has yet to emerge, as evidenced by the continuous influx of recent studies [8,[38][39][40].…”