Electrocatalytic oxidation and determination of hydrazine in alkaline medium through in situ conversion thin film nanostructured modified carbon ceramic electrode

Abstract

• Porous ZIF-67/Co Al-LDH/CCE was fabricated by in situ growth template method in an efficient way. • The porous MOF structure provides enough active sites and high specific surface area. • ZIF-67/Co Al-LDH/CCE displayed remarkably enhanced electrochemical activity in alkaline medium. • Novel hydrazin electrochemical sensor was developed with high stability. • The ZIF-67/Co Al-LDH/CCE was successfully tested for real sample. Here, we report the synthesis of a highly electro-catalytically active composite material by in situ transformation method as a subclass of the zeolite imidazole framework-67/cobalt-aluminum layered double hydroxide (ZIF-67/Co Al-LDH) on the carbon ceramic electrode (CCE). The physicochemical features of the thin film materials were studied by different instrumental techniques such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and electrochemical techniques. The electrochemical properties of the ZIF-67/Co Al-LDH/CCE were characterized using cyclic voltammetry, amperometry and electrochemical impedance spectroscopy. The results revealed that prepared nanocomposite material was efficient as sensitive material for hydrazine (HyZ) determination in low oxidation overpotential. The diffusion coefficient of HyZ (D HyZ = 10.7 × 10 −5 cm 2 s −1 ) and catalytic rate constant (k cat = 2.65 × 10 3 cm 3 mol −1 s −1 ) were determined. Under optimum conditions, the result shows that the fabricated sensor presents a wide linear range from 30 µM to 1200 µM with a detection limit of 7.71 µM and fast response time, high stability, and good repeatability. Finally, the constructed sensor was employed successfully for determination of HyZ in different water samples with satisfactory recovery values.