Electrochemical Oxidation of Saccharose on Copper (Hydr)oxide-Modified Electrode in Alkaline Media

Abstract

A stable copper (hydr)oxide-modified electrode was prepared in 0.5 mol/L NaOH solution by cyclic voltammetry in the range of −250 to 1000 mV. It can be used for electrochemical studies in the range of −250 to 1 000 mV without interfering peaks because there is no oxidation of copper. During an anodic potential sweep, the electro-oxidation of saccharose on Cu occurred by the formation of Cu III and this reaction also occurred in the early stages of the reversed cycle until it is stopped by the negative potentials. A mechanism based on the electro-chemical generation of Cu III active sites and their subsequent consumption by saccharose was proposed, and the rate law and kinetic parameters were obtained. The charge transfer resistance from theoretical and impedance studies was used to verify the mechanism. Under chronoamperometry regimes, the reaction followed Cottrellian behavior. The transfer of up to 21 electrons was observed in further investigations of the electro-oxidation of saccharose on a (hydr)oxide Cu rotating disk electrode. The electrochemical oxidation of saccharose on a copper (hydr)oxide-modified electrode by the electrochemical generation of Cu III active sites and their consumption by saccharose is discussed.