Facile synthesis of N-doped hollow carbon nanospheres wrapped with transition metal oxides nanostructures as non-precious catalysts for the electro-oxidation of hydrazine

Abstract

In the present work, N-doped hollow carbon nanospheres (N-HCNSs) is prepared by direct carbonization of polyaniline-co-polypyrrole (PACP) hollow spheres without template needing. Two different NiO nanostructures (nanosheets and nanowires) are prepared by forming a shell around the N-HCNSs via simple hydrothermal/calcination processes ([email protected] and [email protected]). The morphology and structure of the nanostructures are characterized using field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The prepared nanocomposites are used as catalysts for the electrocatalytic oxidation of hydrazine. The electrocatalytic activities of different electrodes including GCE, N-HCNSs/GCE, NiO-NPs/GCE, [email protected]/GCE and [email protected]/GCE for hydrazine oxidation are compared using cyclic voltammetry, chronoamperometry, and electrochemical impedance spectroscopy (EIS) techniques. The obtained results revealed significantly higher electroactive surface area (ECSA), higher catalytic activity, lower over-potential and better stability of [email protected]/GCE toward the hydrazine electro-oxidation. This observation can be related to the different parameters such as the unique nanowires structure with free pores and the enlarged specific surface area, high conductivity of N-HCNSs, and the synergistic effect between NiO and N-HCNSs.