Electrocatalytic activity of niquel hexacyanoferrate supported on reduced graphene oxide for electrooxidation reaction Glycerol

The study of glycerol electrooxidation was evaluated over a vitreous carbon (VC) electrode chemically modified by a reduced graphene oxide supported nickel hexacianoferrate. We have characterized the prepared NiHCF/rGO electrode by means of X-ray diffraction (DRX), Energy-dispersive X-ray spectroscopy (EDX) and Scanning electron microscopy. The material electrocatalytic activity was evaluated by cyclic voltammetry, cronoamperometry and electrochemical impedance spectroscopy. Voltamograms registered at basic environments for the NiHCF/rGO electrode presented the formation of well defined redox peaks associated with the redox couple Ni(II)/Ni(III). These results show that the NiHCF/rGO electrode significantly enhances electrocatalytic activity for glycerol oxidation in comparison to the unmodified VC electrode. By using Laviron theory we were able to calculate, for the glycerol oxidation reaction, the charge transference speed constant (ks) and the electron transference coefficient (α) obtaining the values of 0,55 e 0,19 s-1 respectively. The anodics currents increased with increasing concentrations of OH- and glycerol. By means of cronoamperometry we have determined glycerol diffusion coefficient (D = 2,8 Χ 10-4 cm2 s-1). The electrochemical impedance spectroscopy data show that the charge transference resistence decreases with an increase in glycerol concentration therefore demonstrating the efficiency of the NiHCF/rGO electrocatalyst for this reaction.