Enhancing the Cyanide Sensing Performance of the CuBi2O4 Nanoflakes by Polyaniline

Abstract

Background: Cyanide (CN-) belongs to dangerous anion pollutants owing to its toxicity at low level. The development of an efficient method for the cyanide detection in aqueous solution is of tremendous importance for protecting the environment and human health. Polyaniline/CuBi2O4 composite modified electrode possesses good electro-catalytic activity towards cyanide. Objective: The aim is to synthesize polyaniline/CuBi2O4 nanoflakes by a facile hydrothermal route using the CuBi2O4 nanoflakes and polyaniline as the raw materials, and research the electro-catalytic activity towards cyanide of the composite nanoflakes. Methods: Polyaniline/CuBi2O4 nanoflakes were synthesized by a facile hydrothermal route using the CuBi2O4 nanoflakes and polyaniline as the raw materials. The structure, morphology, chemical bonding and electro-catalytic activity towards cyanide of the composite nanoflakes were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and electrochemical measurements. Results: The obtained composite nanoflakes are composed of tetragonal CuBi2O4 phase. Amorphous polyaniline nanoscale particles with the size of about 50 nm attach to the surface of the CuBi2O4 nanoflakes. The nanoflakes modified glassy carbon electrodes (GCEs) were used for the determination of cyanide. A pair of quasi-reversible cyclic voltammetry (CV) peaks are located at +0.25 V and +0.33 V, respectively at the polyaniline/CuBi2O4 nanoflakes modified GCE. The linear range and detection limit are 0.01-2 mM, 3.1 μM and 0.001-2 mM, 0.39 μM for CuBi2O4 nanoflakes modified GCE, and polyaniline/CuBi2O4 nanoflakes modified GCE, respectively. Conclusion: Polyaniline/CuBi2O4 nanoflakes modified GCE shows good reproducibility and stability for cyanide detection. The electro-catalytic activity towards cyanide of the CuBi2O4 nanoflakes modified GCE can be greatly enhanced by the polyaniline.