Electrochemical Characteristics of a Copper Hexacyanoferrate (CuHCNF) Modified Composite Carbon Electrode and Its Application toward Sulfite Oxidation

Abstract The sol‐gel technique was used to construct copper hexacyanoferrate (CuHCNF) modified composite ceramic carbon electrodes (CCEs). The modified CCE was prepared manually by carefully mixing the dispersed graphite powder with Cu powder. Copper hexacyanoferrate (CuHCNF) film has been deposited on the surface of CCE by a simple electroless dipping into a potassium hexacyanoferrate solution method. The cyclic voltammograms of the resulting surface modified CCE under optimum conditions show a well‐defined redox couple due to the K2CuII [FeIII/II(CN)6] system. The electrochemical properties and stability of the modified electrode were investigated by cyclic voltammetry. The effect of different alkali metal cations in the supporting electrolyte on the behavior of the modified electrode was studied and the transfer coefficient (α) and charge transfer rate constant (ks) for the electron transfer between the electrode and modifier layer were calculated. The experimental results show that the peak potential and peak current vary with different alkali metal cations. An extensive study showed that the response of the modified electrode is not affected within a pH range of 2‐8. The modified electrode was used for electrocatalytic determination of sulfite in hard sugar sample.