Investigation On Electrochemical Sensing Based On Metal Oxides Nanocomposites

Nanocomposites not only possess the physical and chemical function of each component, but also have a comprehensive performance produced by the synergy effect between components, thus their electrochemical sensing application will become hot spot. In this thesis, three kinds of electrochemical sensor based on novel nanocomposites were established and used for detection of nitrite and hydrogen peroxide. The study expanded the research contents of electrochemical sensors, and broadened the applied scope of nanocomposites. The thesis consisted of three chapters and the main contents were summarized and presented as follows:1. A new nanosheet structure material (Ag/TiO2-GO) is synthesized by the liquid phase method and used for fabricating nonenzymatic NO2- sensor. The experimental results show that the sensor could detect NO2- in a linear range of 1.0 μM-1.1 mM, a sensitivity of 112.0 μA·mM-1·cm-2, a detection limit of 0.4 μM. Additionally, the sensor is successfully applied in determination of NO2- in two water samples with satisfactory results.2. A new electrochemical sensor for H2O2 was designed based on Cu-CuO/GCE by electrodeposition. The results showed that the sensor could detect H2O2 in a linear range of 15.0 μM-12.0 mM, a sensitivity of 14.5 μA·mM-1·cm-2, a detection limit of 8.6 μM. This study provides a new idea for designing a simple, stable and low cost sensor.3. Through one-step solvothermal and reduction method, Fe3O4@C-Cu is synthesized and used for fabricating nonenzymatic H2O2 sensor. The results showed that the sensor could detect H2O2 in a linear range of 80.0 μM-372.0 mM, a detection limit of 32.6 μM. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference ability.