Ni(II)-baicalein complex modified multi-wall carbon nanotube paste electrode toward electrocatalytic oxidation of hydrazine.

A modified electrode Ni(II)-BA-MWCNT-PE has been fabricated by electrodepositing nickel(II)-baicalein [Ni(II)-BA] complex on the surface of multi-wall carbon nanotube paste electrode (MWCNT-PE) in alkaline solution. The Ni(II)-BA-MWCNT-PE exhibits the characteristic of improved reversibility and enhanced current responses of the Ni(III)/Ni(II) couple compared with Ni(II)-BA-CPE. It also shows good electrocatalytic activity toward the oxidation of hydrazine. Kinetic parameters such as the electron transfer coefficient alpha, rate constant k(s) of the electrode reaction, the diffusion coefficient D of hydrazine and the catalytic rate constant k(cat) of the catalytic reaction are determined. Moreover, the catalytic currents present linear dependence on the concentration of hydrazine from 2.5 microM to 0.2 mM by amperometry. The detection limit and sensitivity are 0.8 microM and 69.9 microA mM(-1), respectively. The modified electrode for hydrazine determination is of the property of simple preparation, good stability, fast response and high sensitivity.