Construction of La2O3-CeO2 Composites Modified Glassy Carbon Electrode as a Novel Electrochemical Sensor for Sensitive Detection of Nitrite

An electrochemical sensor for the determination of nitrite based on La2O3-CeO2 composite modified glassy carbon electrode (La2O3-CeO2/GCE) was fabricated in this study. La2O3-CeO2 composites were prepared by reflux condensation, and their morphology and structure were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrochemical behavior of nitrite on the modified electrode was investigated by cyclic voltammetry (CV) and an irreversible oxidation peak emerged at 0.7 V (pH = 7). The effects of scan rate and pH on electron transfer efficiency of fabricated electrode were investigated by CV. Under the optimum conditions, the modified electrode performed outstanding electrocatalytic activity for nitrite detection with a linear range of 0.25-4000 mu M and a low detection limit of 0.015 mu M (S/N = 3). The constructed sensor was successfully used for the determination of nitrite in real water samples with satisfactory results (recoveries between 94.0% and 106.6%). It provides a foundation and reference for the determination of nitrite in various environmental samples.