Electrochemical behavior of nano-composite containing 4-hydroxy-2-(triphenylphosphonio)phenolate and multi-wall carbon nanotubes spiked in carbon paste and its application for electrocatalytic oxidation of hydrazine

The electrochemical study of a 4-hydroxy-2-(triphenylphosphonio)phenolate (HTP) multi-wall carbon nanotubes modified carbon paste electrode, HTP-MWCNT-CPE, as well as its efficiency for electrocatalytic oxidation of hydrazine was conducted using cyclic voltammetry, chronoamperometry and differential pulse voltammetry. Cyclic voltammetry was used to investigate the redox properties of this modified electrode at various pHs and scan rates. The apparent charge transfer rate constant, ks, and the charge transfer coefficient, α, for the electron transfer between HTP and MWCNT-CPE were calculated within pH range of 2.0–9.0. It was found that the peak potential of hydrazine oxidation at the modified electrode dramatically changes to less positive potential than that of MWCNT-CPE. Chronoamperometry was used to estimate the diffusion coefficient of hydrazine. The kinetic parameters such as the electron transfer coefficient, α, and the heterogeneous rate constant, k′, for the oxidation of hydrazine at HTP-MWCNT-CPE surface were determined using cyclic voltammetry. Differential pulse voltammetry exhibited three linear dynamic ranges and a detection limit of 0.13 μM of hydrazine. The modified electrode was shown to have good sensitivity, stability, reproducibility, hence employed for the determination of hydrazine in real samples.