Electrocatalytic oxidation of hydrazine at a pyrocatechol violet (PCV) chemically modified electrode

Abstract

A stable electroactive thin film of pyrocatechol violet (PCV) was electrochemically deposited on the surface of glassy carbon electrode previously activated in alkaline solution. The cyclic voltammograms of the modified electrode indicated that the surface confined PCVs were strongly dependent on the solution pH, as anticipated for quinone/hydroquinone functionalities. The PCV-modified glassy carbon electrode exhibited catalytic activity toward the electro-oxidation of hydrazine, which appeared as a reduced overpotential in a wide operational pH range (pH 5.0–10.0). The overall number of electrons involved in the catalytic oxidation of hydrazine and the number of electrons involved in the rate-determining step were four and one, respectively. The catalytic rate constant of the modified electrode for the oxidation of hydrazine was determined using the cyclic voltammograms recorded at sufficient high scan rates. The diffusion coefficient of hydrazine was also estimated using chronoamperometry. It has been shown that using the PCV-modified electrode, hydrazine can be determined by amperometry with high sensitivity and good limit of detection (4.2 μM).