A sensitive and selective amperometric hydrazine sensor based on palladium nanoparticles loaded on cobalt-wrapped nitrogen-doped carbon nanotubes

In this work, a sensitive and selective hydrazine amperometric sensor was developed for the first time using palladium nanoparticles (Pd NPs) loaded on cobalt nanoparticles (Co NPs) wrapped in nitrogen-doped carbon nanotubes (Pd/Co-NCNTs). The Co-NCNTs synthesized by facile one-step pyrolysis combine with Pd NPs to exhibit high catalytic response and low overpotential for hydrazine oxidation . The morphology and composition of prepared nanomaterial were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Raman spectroscopy. The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize Pd/Co-NCNTs for electrochemical oxidation performance of hydrazine and define the mechanism of hydrazine reaction at the electrode. Under the optimized conditions, an amperometric sensor for hydrazine detection was established, and exhibited a wide linear range of 0.05–406.45   μM with low detection limit (S/N   =   3) of 0.007   μM and the response of the sensor for hydrazine detection lies within 2   s. The prepared sensor demonstrates a long-term stability along with a very good sensitivity.