Electrochemical Exfoliation of Graphite in Supercritical Media
- PDF / 783,457 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 6 Downloads / 207 Views
AL CHEMISTRY
Electrochemical Exfoliation of Graphite in Supercritical Media A. A. Nikiforova, M. S. Kondratenkob,*, O. O. Kapitanovac, and M. O. Gallyamova,b Presented by Academician A.R. Khokhlov April 6, 2020 Received April 7, 2020; revised April 17, 2020; accepted April 27, 2020
Abstract—The possibility of electrochemical intercalation of tetrafluoroborate anion into graphite from a supercritical electrolyte containing carbon dioxide, acetonitrile as a co-solvent, and tetrabutylammonium tetrafluoroborate has been demonstrated for the first time. Keywords: supercritical electrolyte, highly oriented pyrolytic graphite, exfoliation DOI: 10.1134/S0012501620060020
Graphene and graphene-like materials are considered to be promising for a wide range of tasks, for example, creating “ink” with different electrical conductivity depending on the synthesis method for twodimensional and three-dimensional printing to produce flexible electronic devices (solar cells, transistors, memristors, etc.), gas separation membranes, biosensors, “smart clothes” [1–3], as conductive and reinforcing additives and matrices in batteries and composites [4], etc. In this regard, an urgent task today is the development of the synthesis of graphene and graphene-like materials with controlled physicochemical properties (composition, structure, morphology) [4]. The synthesis of graphene and graphene-like materials is based on an increase in the interplanar distance, a weakening of the van der Waals forces between graphene layers, followed by the delamination of graphite. For this, as a rule, chemical oxidation with inorganic oxidizing agents is used [5]. This approach leads to disruption of the graphite structure and its oxidation so that the product should be purified from acid and then reduced. Electrochemical methods based on ion intercalation (i.e., filling the interplanar distances in graphite with ions) in aqueous [6] and nonaqueous [7] electrolytes with delamination of intercalated graphite make the synthesis faster, but
also require product purification from the electrolyte. To obtain graphene without purification, synthetic approaches based on the exfoliation of graphite in a supercritical medium using sonication or sharp decompression [8] are also used, but usually such approaches are characterized by a low yield of a thinlayer (less than five layers) product. Thus, currently there is no fast and efficient method for the synthesis of graphene/graphene oxide; therefore, the search for such methods is an urgent task. To solve it, we propose to combine two approaches and carry out the synthesis of graphene by electrochemical oxidation in a supercritical electrolyte. Thanks to their synergy, the graphene production can be expected to be more efficient and faster. An important synthetic advantage of using intercalation in a supercritical electrolyte is that there is no need for the step of washing the intercalated graphite from the electrolyte, since after decompression it is possible to obtain a dry sample. As a rule, the necessary stage
Data Loading...
