Facile preparation of Ni(OH)2-MnO2 hybrid material and its application in the electrocatalytic oxidation of hydrazine.

A surfactant-free synthetic methodology is reported for the preparation of Ni(OH)2-MnO2 hybrid nanostructures. For comparative study, MnO2 and Ni(OH)2 were also synthesized. Materials were characterized by X-ray diffraction, nitrogen sorption, scanning electron microscopy, and transmission electron microscopy. Ni(OH)2-MnO2 modified electrode is fabricated for the determination of hydrazine. The electrochemical oxidation of hydrazine was investigated using cyclic, linear sweep voltammetries, and chronoamperometry methods. The Ni(OH)2-MnO2 modified electrode showed hydrazine oxidation with decrease in the over voltage and increase in the oxidation peak current, when compared to MnO2, Ni(OH)2, and bare GCE. pH was optimized to obtain the best peak potential and current sensitivity. Chronoamperometry was used to estimate the diffusion coefficient of hydrazine. The kinetic parameters such as overall number of electrons involved in the catalytic oxidation of hydrazine and the rate constant (k) for the oxidation of hydrazine at Ni(OH)2-MnO2 modified electrode were determined. The Ni(OH)2-MnO2 modified electrode exhibited good sensitivity, stability, and reproducibility in hydrazine sensing.