Electrocatalytic Behavior of Nano Zeolite Modified Carbon Paste Electrode forOxidation of Hydrazine

liquid fuels such as hydrazine, alcohols, alkaline borohydride and hydrazine solutions have beenused in the direct liquid fuel cells [1]. several companies have started to supply power sourcesbased on fuel cell technology to the market. The potential applications of fuel cells are broad, frommobile devices to automobiles and space ships. At present, one of the main focus of fuel cellresearch is portable devices, such as mobile phones, mp3 players and notebooks [2,3]. Hydrazine iscommonly used in some industrial applications such as catalyst, corrosion inhibitor , reducingagent,antioxidant, emulsifier starting material in the production of some insecticides andherbicides, pesticides, dye stuffs, explosive, and the preparation of several pharmaceuticalderivatives [4]. In the case of oxidation of hydrazine using electrochemical procedures,unfortunately, ordinary carbon electrodes have a number of limitations for electrochemicaldetection of hydrazine, such as low sensitivity and reproducibility, high overpotential for oxidation,low stability, and slow electron transfer [5]. Therefore, a main attention has been focused on thedevelopment of materials capable of the catalytic electrooxidation of hydrazine. Recently, manygroups introduced several compounds to improve the anodic oxidation of hydrazine. Zeolitemodifiedelectrodes have been developed for the determination of various compounds and the useof a mixture of a zeolite and graphite powder in various forms has been projected. Zeolitesupportedelectrocatalysts can be subjected to improve the performance of the Electrocatalyticresponses with reduced over potentials and increased voltammetric/amperometric signals allowinglow detection limits and high sensitivities. This paper intends to introduce a novel zeolite modifiedcarbon paste electrode based on Ni modified synthesized nano ZSM-5 crystallites for theelectrocatalytic oxidation of ethanol. The rate constant of the oxidation process is calculated usingchronoamprometric studies.The used nano ZSM-5 zeolite was synthesized as literature [6]. Allother used chemicals were purchese from Merc. The electrochemical experiments were performedon a potentiostat/galvanostat (sama 500-c Electrochemical Analysis system, sama, Iran). SCE was56used as the reference electrode, a platinum wire as the auxiliary electrode, and a home-made carbonpaste electrode (ca. 3.4 mm internal diameters) as the working electrode. Appropariated ammountof synthesized nano zeolite was lightly ground and immersed to 10 ml 1 M NiCl2 solution for 1 h.Then the solid was dried. The 30% (W/W) Ni2+-zeolite to graphite powder paste was made bymixing the given quantity of Ni2+-zeolite and graphite powder in diethyl ether and the solvent wasevaporated by stirring a mixture. Then paraffin was blended by hand mixing and the resulting pastewas inserted in the bottom of a glass tube. The electrical connection was implemented by a copperwire fitted into the opposite opening of the glass tube. For the comparission the unmodified carbonpaste was prepared. Obtained results show that proposed modified carbon paste electrode can usedfor electrocatalytic oxidation of hydrazine as a fuel for fuel cell and the catalytic rate constant forthis process was calculated as 9.6*103 M-1 s-1 .

Keywords:

Hydrazine , Nano Zeolite , catalysis , Cyclic Voltametry , Fuel Cell