Synthesis and investigation of electrocatalytic effect of Ag@pt core-shell nanoparticles supported on carbon nanotubes (CNTs) and modifier for determination of hydrazine

Hydrazine and its derivatives are widely used in chemical and pharmaceutical industries. They are mainly used as antioxidants, explosives, fuel cells, pesticides, herbicides, dyes and synthesis of insecticides. Despite this advantage, hydrazine is a toxic material. Therefore, an easy and sensitive analytical method for detection of hydrazine is warranted [1-2]. The electrochemical methods using chemically modified electrodes (CMEs) have been widely used as sensitive and selective analytical methods for the detection of the trace amount of important compounds [3]. In the present research, derivative pyrazole as modifier was synthesized in the laboratory of yazd university and characterized by spectroscopy techniques. The Electrochemical behavior of modifier was investigated. A pair of reversible peaks are observed at Ep.a=0.185V and Ep.c=0.100V versus SCE, and ΔEP= (Ep.a-Ep.c) was 0.085V. An Ag@pt nanoparticles core-shell supported on carbon nanotubes (Ag@pt NPs/CNT/CS) was synthesized by a colloidal method and a chemical reduction method with sodium borohydride and ethylene glycol as reducing agents [4]. Mixture of modifier and Ag@pt NPs/CNTs/CS with mass ratio 3:1 was prepared. Then, 3µL of solution drop casting on glassy carbon electrode and at room temperature was placed to dry. In this research, electrocatalytic activity of Ag@pt NPs/CNT/CS/glassy carbon electrode (GCE) has been studied by cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV).It has been found that under optimum condition (pH=8) in cyclic voltammetry, the oxidation of hydrazine occurs at a potential about 180 mV less positive than that of as unmodified glassy carbon electrode. The dynamic linear range, current sensitivity and detection limit for hydrazine were evaluated by DPV. The detection limit of hydrazine was 0.1 µM. Some advantages of using the modified electrode are ease of preparation, potential window, and ease of modification, excellent electrical conductivity and increasing the surface of the electrode. The sensor produced good sensitivity, selectivity and reproducibility and stability properties.