The Preparation Of Nanocomposites Based On RTILs And Their Application In Electrochemical Sensor

Ionic liquids are melts of organic salts existing in the liquid state below room temperature.The properties of room temperature ionic liquids (RTILs) included the low melting point, zero pressure of saturated vapor, the wide electrochemistry windows, high polarity, electrochemical stability and conductivity. In developing electrochemical sensors the above characteristics of ionic liquids are rather important. Especially, in development of composite materials that can be used in electrochemical sensors. Their applications in electrochemistry sensor were introduced and used in this dissertation. We used screen printed carbon electrodes(SPCEs) modified with the ionic liquids-gold, ionic liquids-MWCNTs and ionic liquids-Fe3O4composites to carry out the devise of the electrochemistry sensors respectively. This dissertation includes five chapters, the primary researeh work is as follows:In the chapter one, firstly, we introduced the development、structure、 character and the application of room temperature ion liquid, especially, in electrochemistry sensors. On the other hand, we introduced the types、characters and methods of chemically modified electrode. At last, we introduced the application of nanomaterials in electrochemistry sensors.In the chapter two, we focused on the Room temperature ionic liquids (RTILs)-gold nanoparticles composite used to prepare the electrochemistry sensor, with different viscosity and surface tension, such as [C2mim][NTf2],[C4mim][NTf2],[C4dmim][NTf2], and [C6mim][FAP], and gold nanorods(GNRs) and quasi-platonic gold nanoparticles (QPGNPs) have been chosen for the measurements,which has been demonstrated to overcome a major obstacle for creating an extremely thin layer of RTILs on the surface of electrode for membrane-free amperometric gas sensors. Besides larger current and ultra-fast response, the resulting RTILs/gold nanomaterials composite brings new capabilities for membrane-free gas sensors by combining the advantages of RTILs and superior catalytic effect of gold nanomaterials. Such as:real diversity, morphology-dependent activity, and lower reduction potentials compared to conventional SPCE. The response of the sensor was quantified by both cyclic voltammetry and chronoamperometry, and the sensor do possess the characteristics required for a really versatile, long-lived membraneless sensor and the excellent development in the future.In the chapter three, MWCNTs-RTILs composite were employed as preconcentration and charge supporter to study the characteristic of electrochemistry impedance spectra(EIS) of1,2,4,5-tetrachlorobenzene (TeCB) assisted with room temperature ionic liquid. The surface characteristic of MWCNT/TeCB was investigated by SEM and XPS. The EIS method proposed was successfully applied to study the electrochemical behaviors and further quantitative of the treated and pristine MWCNT/TeCB at low concentration levels, and the sensitivity of treated MWCNT-RTILs composites in dectecting TeCB was two times that of pristine-RTILs composites. Good selectivity was illustrated through the eletrochemical impedance with aromatic and aliphatic compounds.In the chapter four, The SPCEs modified with RTILs-Fe3O4have been investigated for their suitability to determine arsenic in water in acetic buffer solution. Square Wave Anodic stripping voltammetry (SWASV) was used to study the electrochemical behaviour of As(Ⅲ). At SPCEs modified with a certain amount of RTILs, Fe3O4, and RTILs-Fe3O4composites, the efficiency of SPCEs modified RTILs-Fe3O4composites in detecting As(Ⅲ) in water solution were the best. And the detection limit of C4dmimNTf2-Fe3O4composites was the lowest compared to other three RTILs composites. The composites can be used for monitoring arsenic at concentration0.0096ppb with a preconcentration time of120s at-0.5V vs. Ag in pH5.0acetic buffer solution, which is far below the guideline value given by World Health Organization. The electrode was applied for highly sensitive detection of As(Ⅲ) in water.In chapter five, we summarized and gave object comments on the results obtained. At the same time, we pointed out the problems and shortcomings of these experiments. At last, some good objects and schemes of further research were proposed in furture.