Electrochemical sensing of nitrite using a glassy carbon electrode modified with reduced functionalized graphene oxide decorated with flower-like zinc oxide

A nanocomposite consisting of flower-like zinc oxide (ZnO) and reduced functionalized graphene oxide (rFGO) was prepared via a hydrothermal route, and characterized by spectrophotometry, photoluminescence, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The nanocomposite was deposited on the surface of a glassy carbon electrode and studied using impedance spectroscopy. It exhibits excellent electrocatalytic activity toward the oxidation of nitrite. At a working potential of 0.9 V (vs. Ag/AgCl), it displayed a higher current and lower over potential (reduced by up to similar to 200 mV) than controlled electrodes. This is attributed to the synergistic catalytic effects of the ZnO and rfGO. The oxidation current is linearly related to the concentration of nitrite in the 10 mu M to 8 mM range, and the detection limit is 33 mu M. Its excellent electrocatalytic activity, wide linear range, low detection limit, high sensitivity, and rapid response time make this nanocomposite-based electrode a potential candidate for practical applications.