Hierarchical composites based on near-spherical ZnO attached on nitrogen-doped reduced graphene oxide for enhanced nitrite electrochemical sensing property

A hierarchical near-spherical ZnO (ns-ZnO)/Nitrogen-doped reduced graphene oxide (N-rGO) nanocomposite was synthesized via a facile hydro/solvo-thermal route. Then, a non-enzymatic nitrite electrochemical sensor (ns-ZnO/N-rGO/GCE) was obtained by modifying glassy carbon electrode (GCE) with the prepared nanocomposite. More adsorption sites and electro-catalytic active sites were provided at the electrode interface thanks to the formation of hierarchical structure, making the fabricated GCE possess a remarkable amperometric sensing property for nitrite. The limit of detection (LOD) was as low as 0.08 μM, and the detection range was as broad as 0.037 μM–5.9 mM. Furthermore, this sensor showed satisfactory recovery for nitrite in genuine samples including ham sausage, pickle and tap water, suggesting the potential practical application performance of ns-ZnO/N-rGO/GCE in the fields of food analysis and environmental monitoring.