Enhancing the Cyanide Sensing Performance of the CuBi2O4 Nanoflakes by Polyaniline

Background: Cyanide (CN-) belongs to dangerous anion pollutants owing to its toxicity at a low level. The development of an efficient method for cyanide detection in an 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 electrocatalytic 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 a tetragonal CuBi2O4 phase. Amorphous polyaniline nanoscale particles with a 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 were located at +0.25 V and +0.33 V, respectively, at the polyaniline/CuBi2O4 nanoflakes modified GCE. The linear range and detection limit were 0.01-2 mM, 3.1 μM, 0.001-2 mM, and 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.