Nonenzymatic Amperometric Sensor for Nitrite Detection Based on a Nanocomposite Consisting of Nickel Hydroxide and Reduced Graphene Oxide

An efficient non-noble metal eletrocatalyst, nickel hydroxide/reduced graphene oxide nanocomposite (Ni(OH)(2)/sr-GO), is synthesized in the absence of reductants and alkali by a simple one-step solvothermal method. The morphology, structure, and composition of the Ni(OH)(2)/sr-GO nanocomposite is characterized by various analytical techniques like scanning electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy. The Ni(OH)(2)/sr-GO nanocomposite is then used to construct a nonenzymatic amperometric sensor for highly sensitive detection of nitrite. The result shows that the Ni(OH)(2)/sr-GO nanocomposite possesses superior electrocatalytic ability toward nitrite. The electrochemical performance of the Ni(OH)(2)/sr-GO is evaluated by electrochemical impedance spectroscopy, chronocoulometry, and cyclic voltammetry. Under the optimal conditions, the electrochemical sensor for nitrite detection exhibits a linear range from 0.1 to 663.6 mu M, with a detection limit of 0.07 mu M (S/N=3). In addition, the sensor provides favorable selectivity, reproducibility, and stability, and can be successfully applied for the detection of nitrite in spiked water samples. Recoveries range between 95 and 108 %.