Analytical Sciences

Application of a Palladium Hexacyanoferrate Film-Modified Aluminum Electrode to Electrocatalytic Oxidation of Hydrazine

Habib RAZMI, Azadeh AZADBAKHT, and Moayad Hossaini SADR

Electrochemistry Research Lab., Faculty of Science, Azarbaijan University of Tarbiat Moallem P. O. Box: 53714-161, Tabriz, Iran

A palladium hexacyanoferrate (PdHCF) film as an electrocatalytic material was obtained at an aluminum (Al) electrode by a simple electroless dipping method. The modified Al electrode demonstrated a well-behaved redox couple due to the redox reaction of the PdHCF film. The PdHCF film showed an excellent electrocatalytic activity toward the oxidation of hydrazine. The electrocatalytic oxidation of hydrazine was studied by cyclic voltammetry and rotating disk electrode voltammetry techniques. A calibration graph obtained for the hydrazine consisted of two segments (localized at concentration ranges 0.39 - 10 and 20 - 75 mM). The rate constant k and transfer coefficient α for the catalytic reaction and the diffusion coefficient of hydrazine in the solution D, were found to be 3.11 × 10³ M^-1 s^-1, 0.52 and 8.03 × 10^-6 cm² s^-1 respectively. The modified electrode was used to amperometric determination of hydrazine in photographic developer. The interference of ascorbic acid and thiosulfate were investigated and greatly reduced using a thin film of Nafion on the modified electrode. The modified electrode indicated reproducible behavior and a high level of stability during electrochemical experiments, making it particularly suitable for analytical purposes.

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