Highly sensitive amperometric hydrazine sensor based on novel α-Fe2O3/crosslinked polyaniline nanocomposite modified glassy carbon electrode

Fabrication of efficient chemical sensors is a prime strategy for detecting trace levels of environmental species, but predominantly limited by slow response time, relatively low sensitivity and poor selectivity. Here, we demonstrate, for the first time, the synthesis of a novel nanocomposite of alpha-Fe2O3/crosslinked polyaniline (alpha-Fe2O3/CPANI) via a simultaneous gelation and polymerization process. The newly prepared alpha-Fe2O3/CPANI nanocomposite was employed as an efficient hydrazine chemical sensor with high sensitivity and selectivity. The XRD, XPS and HR-TEM results confirmed the presence of PANI and revealed a well-crystalline, structurally uniform crystals of rhombohedral alpha-Fe2O3 phase with particle sizes <50 nm and distinctly lattice fringes of 3.7 angstrom. The electrochemical detection of hydrazine was conducted at alpha-Fe2O3/CPANI modified glassy carbon electrode (GCE) by the cyclic voltammetry and amperometry techniques and compared with bare GCE or pure alpha-Fe2O3. Comparing to bare GCE or pure alpha-Fe2O3, the alpha-Fe2O3/CPANI nanocomposite modified GCE shows a superior sensing performance, leading to a remarkable sensitivity of 1.93 mu A mu M-1 cm(-2), a very low limit of detection (LOD) of 0.153 mu A at (S/N = 3), a wide linear range of hydrazine concentrations from 0.2 mu M to 40 mu M, with a correlation coefficient (R-2) = 0.9983 and a response time <12 s. Additionally, the present alpha-Fe2O3/CPANI modified electrode exhibits electrochemical stability and high selectivity as a negligible cross-sensitivity to common bio-active interfering species and several metal ions was observed. Furthermore, the electrocatalytic reaction obeys the first order kinetics with respect to hydrazine concentration with a diffusion dominated process. Such a novel nanocomposite of alpha-Fe2O3/CPANI represents a proper electrode material for highly efficient detection of hydrazine by electrochemistry. (C) 2016 Elsevier B.V. All rights reserved.