Oxygen reduction on graphene sheets functionalised by anthraquinone diazonium compound during electrochemical exfoliation of graphite

• Published in: Electrochimica acta Vol. 267; pp. 246 - 254
• Main Authors: Mooste, Marek, Kibena-Põldsepp, Elo, Ossonon, Benjamin Diby, Bélanger, Daniel, Tammeveski, Kaido
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 20-03-2018; Elsevier BV
• Subjects: Anthraquinone; Aqueous solutions; Coated electrodes; Diazonium salts; Electrochemical exfoliation; Electrodes; Exfoliation; Glassy carbon; Graphene; Graphite; Hydrogen peroxide; Molecular chains; Oxygen reduction; Oxygen reduction reactions; Rotating disks; Sheets; Sulfuric acid; Thermogravimetric analysis; Oxygen reduction; Anthraquinone; Diazonium salts; Graphene; Electrochemical exfoliation
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2018.02.064

In this paper, the oxygen reduction reaction (ORR) was studied on anthraquinone (AQ) modified and unmodified graphene sheets in aqueous solutions. AQ-grafted graphene sheets were prepared by one-pot synthesis procedure using electrochemical exfoliation of graphite and in situ spontaneous diazonium reduction at the same time in 0.1 M H2SO4. Unmodified and AQ-grafted graphene were characterised by thermogravimetric analysis and Raman spectroscopy. Covalent attachment of AQ on graphene was ascertained. The ORR was studied in acidic and alkaline electrolytes by the rotating disc electrode method. In both media, the prepared graphene materials were more active towards the ORR than bare glassy carbon. In alkaline solution, the number of electrons transferred per O2 molecule for AQ-modified and unmodified graphene coated glassy carbon electrodes was higher than two indicating that the formed hydrogen peroxide is partially further reduced. In addition, stability testing of the prepared electrodes during potential cycling yielded a small loss of activity.
•Graphene sheets were prepared by electrochemical exfoliation of graphite in acid media.•The anthraquinone functionalised graphene was prepared using a one-pot process.•Graphene-based materials were studied by Raman spectroscopy and thermogravimetry.•Unmodified and AQ-grafted graphene were studied as catalysts for oxygen reduction.