Hydrazine detection by shape-controlled palladium nanostructures on carbon nanotube thin films

Abstract

In this article, the electrodeposition of palladium (Pd) nanostructures on flexible and transparent single-walled carbon nanotube (SWCNT) thin films was described. Four different morphologies of Pd nanostructures were synthesized by controlling the potentials. Octahedral-like and flower-like nanostructures were observed at +0.3V and −0.1V, respectively. With a further driving potential decrease, cubic and spherical nanostructures were obtained in turn at 0.0V and −0.5V. The Pd nanostructures were confirmed by XRD data. Subsequently, the fabricated Pd nanostructures on SWCNT thin films were employed as electrodes for hydrazine detection. The electrochemical oxidation of hydrazine by Pd nanostructures was investigated by cyclic voltammetry and amperometry. As results, the specific sensitivities of four Pd nanostructures were 1123 μA mM cm−2 (octahedron), 899 μA mM cm−2 (flower), 827 μA mM cm−2 (cube), and 275 μA mM cm−2 (sphere). The detection limits were 5.90 μM (octahedron), 2.56 μM (flower), 2.85 μM (cube), and 4.83 μM (sphere).The morphology effect of Pd nanostructures on hydrazine oxidation is dependent on the relative fraction of (100), (110), and (111) facets which are associated with the shape. The (111) facet dominant Pd nanostructures exhibited the higher catalytic activities than Pd nanostructures with (100) and (110) facets.