Au-SH-SiO2 nanoparticles supported on metal-organic framework (Au-SH-SiO2@Cu-MOF) as a sensor for electrocatalytic oxidation and determination of hydrazine

A new electrocatalyst; Au-SH-SiO2 nanoparticles immobilized on the metal-organic frameworks (MOFs) was synthesized and characterized by scanning electron microscopy (SEM), the transmission electron microscopy (TEM) and cyclic voltammetry (CV). The prepared electrocatalyst immobilized onto the surface of a glassy carbon electrode (GCE) to obtain Au-SH-SiO2@Cu-MOF/GCE. The sensor showed good electrocatalytic activity toward the oxidation of hydrazine in the neutral phosphate buffer solution (pH 7.0). The kinetic parameters such as the electron transfer coefficient (alpha) and the catalytic rate constant (k(cat)) for the oxidation of hydrazine were determined. The diffusion coefficient (D) of hydrazine in solution was also calculated by chronoamperometry. The potential application of the sensor was demonstrated by applying to the analytical determination of hydrazine concentration. Our results showed that the sensor had good electrocatalytic activity toward determination of hydrazine and exhibited a low detection limit (0.01 mu M), a wide linear range (0.04-500 mu M), and high sensitivity (0.1 mu A mu M-1) as well as good stability and repeatability. The sensor has been successfully applied to determine hydrazine in water samples with good accuracy and precision. (C) 2012 Elsevier Ltd. All rights reserved.