Investigation Of Hydrogen Peroxide And Hydrazine Electrochemical Sensing Based On Three Kinds Of Nanocomposites

Nanomaterials and their composites have received increasingly attention because of their unique composition,structure and properties.Electrochemical sensors based on nanomaterials and their composites has become one of the research hotspots in the field of electrochemical analysis.In this thesis,three kinds of nanocomposites were prepared and then were employed to construct H₂O₂ and N₂H₄ electrochemical sensors.New methods for the analysis and determination of H₂O₂ and N₂H₄ were established.The study not only enriched the content of electrochemical sensing to a certain extent,but also broadened the application range of nanomaterials.The thesis contained three chapters,and the main research contents were as follows:1.Ag-Fe₂O₃-RGO nanocomposites were successfully synthesized via hydrothermal and chemical reduction method.A non-enzymatic H₂O₂ electrochemical sensor based on this material was fabricated.The relationship between the composition,structure and property of Ag-Fe₂O₃-RGO and the response performance of the sensor was studied.The nanocomposites were characterized by FESEM and TEM.The results showed that Ag NPs were evenly dispersed on the surface of Fe₂O₃-RGO.Electrochemical experiments revealed that Ag-Fe₂O₃-RGO had a good electrocatalytic reduction effect on H₂O₂.The linear ranges of H₂O₂ were from 1.6 ?mol·L-1 to 57 mmol·L-1,with a detection limit of 0.5 ?mol·L-1?S/N = 3?and a sensitivity of 50.8 ?A?mmol·L-1?-1 cm-2.2.FeOOH@PDA was synthesized via oxidation polymerization method,and Ag NPs were reduced and distributed on the surfaces of FeOOH@PDA with the employment of PDA as reductant.The electrochemical sensor based on FeOOH@PDA-Ag nanocomposites was constructed.The effect of the composition,structure and property of FeOOH@PDA-Ag on the response performance of the sensor was studied,and a new method for the detection of H₂O₂ was established.TEM characterization results showed that the as-synthesized Ag NPs were spherical and well-dispersed.Electrochemical studies revealed that FeOOH@PDA-Ag had good effect on electrocatalytic reduction of H₂O₂.The linear range for the determination of H₂O₂ was 7.5 ?mol·L-1?18.8 mmol L-1,the detection limit was 2.5 ?mol·L-1 at a signal-to-noise ratio of 3,and the sensitivity was 11.8 ?A?mmol·L-1?-1 cm-2.3.HNTs@PDA nanocomposites were successfully synthesized,and Au NPs were loaded on HNTs@PDA by electrostatic adsorption.The electrochemical sensor based on HNTs@PDA-Au nanocomposites was constructed.The effect of the composition,structure and property of HNTs@PDA-Au on the response performance of the sensor was explored.TEM and FESEM results showed that Au NPs were well dispersed and had uniform sizes of about 5 run.Electrochemical results revealed that HNTs@PDA-Au as the sensing interface had good effect on electrocatalytic oxidation of N₂H₄.This sensor detected N₂H₄ in the range from 0.75 ?mol·L-1 to 2.8 mmol·L-1,with a sensitivity of 171.7 ?A?mmol· L-1?-1 cm-2 and a detection limit of 0.25 ?mol L-1?S/N = 3?.