Electrochemical behaviour of hydrazine at metal nanoparticles and conductive polymer modified carbon nanotube electrode

ABSTRACT Hydrazine (N2H4) and its derivatives are widely used in industrial applications and agriculture as fuel cells, explosives, antioxidants, rocket propellants, corrosion inhibitor, insecticides and plantgrowth regulators. Hydrazine is an ideal fuel for a direct fuel cell system because it does not exhaust environmentally loading materials such as CO2. In addition, studies have shown that the hydrazine electro-oxidation process does not suffer from any poisoning effect. Carbon nanotubes (CNTs) are new kinds of carbon nanostructure materials possessing properties such as high surface area, high electrical conductivity, chemical stability and significant mechanical strength. They can be used to promote electron transfer reactions when applied as electrode materials in electrochemical devices. The conductor polymers synthesizing with the electrochemical method in the electrode surface are using in recent years. Moreover, metal nanoparticle electrodes modified on this polymer surfaces are densely the subject of the researches. In the nanodimensions, because of changing both physical and chemical characteristics of the substance and very increasing the unit surface field of the substance, active surface area also increase. More pure metal nanoparticle can be obtained with the electrochemical methods. Metal nanoparticles such as Pt and Au are demostrated the catalytical effect on the anodic oxidation of hydrazine. Bromocresol purple (BCP) is a pH indicator. In this study, we have observed the electrochemical behaviour of hydrazine oxidation was investigated at Pt and Au nano particles modified poly(BCP)/CNT/GC electrodes, we have also developed voltammetric methode for determination of hydrazine. Firstly, carbon nano tube was dropped on glassy carbon electrode and obtained electrode was donated as CNT/GCE. Bromcresol purple monomers were polymerized by using cyclic voltammetry at CNT/GCE surface and obtained electrode was donated as poly(BCP)/CNT/GCE. After electrochemical polymerization, Pt and Au particles were doped on the polymer film carbon nanotube GCE surface by electrochemical reduction from their acidic solutions, respectively. Modified electrodes were characterized with electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. The electrochemical behaviour of hydrazine oxidation was investigated at Pt and Au nano particles modified poly(BCP)/CNT/GC electrodes in phosphate buffer solution (PBS). The obtaining results were comparing with other modified and bare electrodes. The best catalytic activity was obtained at Ptnano/poly(BCP)/CNT/GCE and Aunano/poly(BCP)/CNT/GCE due to the shift of oxidation peak to more negative potential values than other electrodes with a highest current value. The peak potential and current oxidation of 1.0 mM hydrazine obtained at Ptnano/poly(BCP)/CNT/GCE (-447 mV, 175,6 µA), Ptnano/CNT/GCE (-461 mV, 133,1 µA) Ptnano/poly(BCP)/GCE (-470 mV, 59,2 µA), Aunano/poly(BCP)/CNT/GCE (-28 mV, 189,4 µA), Aunano/CNT/GCE (-38 mV, 154,7 µA) Aunano/poly(BCP)/GCE (173 mV, 41,4 µA). These results have demonstrated Aunano/poly(BCP)/CNT/GC and Ptnano/poly(BCP)/CNT/GC electrode could be used in fuel cell as anode material. Finally, Aunano/poly(BCP)/CNT/GCE is used determination of hydrazine in Karaçay River waste water sample. This electrode has good stability, sensitivity, reproducibility and selectivity. The proposed method has also been practically and successfully applied for the determination of hydrazine.