Electrochemically prepared colloidal, oxidised graphite

Abstract

A convenient electrochemical method has been developed for the preparation of a functionalised, colloidal graphite (oxide). The method involves the anodic erosion of graphite electrodes by the generated oxygen when using current densities less than 3 mA cm^-2 . The suggested mechanism of formation involves the loss of an electron to form the radical cation followed by hydration to form the enol which is in tautomeric equilibrium with a keto group. The surface areas of the colloid were typically 50–80 m² g^-1 . The particle size distributions were trimodal for ethanoic acid and water but trimodal for sulfuric acid. However, the particle size ranges were significantly wider (40–870 nm) when ethanoic acid was used as the electrolyte than when sulfuric was used (40–630 nm). The colloid had an ion exchange capacity of 7 mmol g^-1 for a monovalent cation. FTIR spectroscopy confirmed the presence of hydroxy (3442 cm^-1) and keto groups (1727 cm^-1). Electrochemical reduction led to the formation of alcohol and aliphatic hydrocarbon groups.

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