A sensitive electrochemical sensor for hydrazine on the Cu-BTZE framework platform

A 3D metal-organic framework (Cu 4.5 (BTZE) 1.5 (OH) 4 (SO 4 )(H 2 O) 1.5 ∙4H 2 O) n (BTZE is 1,2-bis(tetrazol-5-yl) ethane anion) modified carbon paste electrode (Cu-BTZE/CPE) has been fabricated for hydrazine sensing. The Cu-BTZE framework was prepared through a facile solvo-thermal method and characterized by Fourier-transform infrared spectrometry, X-ray diffraction, and scanning electron microscopy. Meanwhile, the electrochemical performances of the modified electrode were studied by electrochemical impedance spectroscopy, chronocoulometry, cyclic voltammetry, and amperometry. Owing to the large electrochemically active surface area and enhanced electron transfer efficiency of Cu-BTZE framework, the Cu-BTZE/CPE showed enhanced electrocatalytic activity toward the oxidation of hydrazine compared with unmodified CPE. Under the optimized conditions, the amperometric current presented linear dependence on the concentration of hydrazine in the ranges of 0.02~1.2 μM and 1.2~500 μM, respectively. The detection limit was 6 nM, lower than the reported Cu-based hydrazine sensors. Furthermore, the sensor has applied for the determination of hydrazine in water samples.