Electrochemical behavior of an indenedione derivative electrodeposited on a renewable sol-gel derived carbon ceramic electrode modified with multi-wall carbon nanotubes: Application for electrocatalytic determination of hydrazine

A novel modified carbon ceramic electrode (CCE) containing multi-wall carbon nanotubes (MWCNTs) was fabricated by a sol-gel technique. The prepared MWCNT-CCE was modified by the electrodeposition of an indenedione derivative. The indenedione modified MWCNT-CCE (IMWCNT-CCE) shows one pair of peaks with surface confined characteristics. According to the theoretical model of Laviron, estimations were made in different pHs of the surface charge transfer rate constant, k(s), and the charge transfer coefficient, alpha, for electron transfer between the indenedione derivative and MWCNT-CCE. The modified electrode shows a highly catalytic activity toward hydrazine electrooxidation at a wide pH range (5-9). The kinetic parameters such as the electron transfer coefficient, alpha, the heterogeneous rate constant, W, and the exchange current of hydrazine at the IMWCNT-CCE were calculated as 0.29 +/- 0.01, 2.7(+/- 0.3) x 10(-3) cm s(-1) and 0.17 +/- 0.03 mu A, respectively. Also, the modified electrode shows an excellent analytical performance for voltammetric determination of hydrazine. Differential pulse voltammetry (DPV) exhibits two linear dynamic ranges, 0.6-8.0 mu M and 8.0-100.0 mu M, and a lower detection limit of 0.29 mu M for hydrazine. Finally, the practical analytical utility is illustrated by differential pulse voltammetric determination of hydrazine in auxiliary cooling water at IMWCNT-CCE and the accuracy of the results is verified in comparison with those obtained from the standard ASTM method. (C) 2008 Elsevier Ltd. All rights reserved.