Three-Dimensional Flower-like Nickel Oxide/Graphene Nanostructures for Electrochemical Detection of Environmental Nitrite

Monitoring environmental pollutants has become a popular topic because of the serious adverse effects of environmental pollutants on human beings and ecosystems. In the present work, a 3D flower-like nickel oxide (NiO)-decorated PDDA (poly(dimethyl diallyl ammonium chloride))-functionalized RGO nanocomposite (NiO/PDDA-RGO) was synthesized via a hydrothermal route combined with an ultrasonic process. The nanocomposite integrates the large surface area and remarkable electrical properties of RGO with the good catalytic activity of NiO and shows great electrochemical signal enhancement toward the electrooxidation of nitrite. In optimal experimental conditions, the as-prepared sensor exhibited excellent nitrite sensing performances, with a wide operating range (5 μM–8 mM), low detection limit (0.98 μM), and high sensitivity (0.0184 μA mM–1 cm–2). Furthermore, the proposed strategy can perform real-time monitoring of nitrite in tap water with satisfactory results. A NiO/PDDA-RGO-based electrochemical sensor also has the advantages of simple preparation, environmental friendliness, low cost, outstanding reproducibility, and stability, which have profound significance for environmental pollution monitoring.