Controllable synthesis of cross-linked 3D ZnO nanosheet toward a nitrite electrochemical sensor

A 3D cross-linked ZnO (cl-ZnO) nanosheets were prepared via a simple one-pot hydrothermal approach, and then characterized by a series of modern advanced technique including XRD, SEM, TEM and XPS. This nanomaterial was used to modify the glass carbon electrode (GCE), obtaining an electrochemical sensor (cl-ZnO/GCE) of which the electrochemical properties were studied using various electrochemical techniques such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The sensor exhibited remarkably enhanced electrocatalytic activity for nitrite ions (NO 2- ) in comparison to that of the commercially available ZnO-modified GCE. Two electrochemical techniques, including chronoamperometry (CA) and linear sweep voltammetry (LSV) were adopted to test the determination performance of the sensor for nitrite, it exhibited a good linear relationship within the range of 0.8 mu mol center dot L-1- 0.462 mmol center dot L-1 and 0.608- 7.84 mmol center dot L-1 evaluated by CA, the limit of detection (LOD) and sensitivity for NO 2- were 0.26 mu mol center dot L-1 (S/ N = 3) and 824.6 mu A (mmol center dot L-1 )-1 cm-2 , respectively. For LSV, the two linearity responses of 0.95 mu mol center dot L-1- 0.515 mmol center dot L-1 and 0.667 mmol center dot L-1- 5.41 mmol center dot L-1 , high sensitivity of 1336.1 mu A (mmol center dot L-1 )-1 cm-2 with low LOD of 0.32 mu mol center dot L-1 were gained. This sensor can be employed to detect trace amount of NO 2- in ham sausage and pickled vegetables successfully, supporting an insight and strategy for more sensitive nitrite electrochemical sensor.