The Preparation And Its Application Of Ionic Liquids Modified Electrodes

Room temperature ionic liquids are organic molten salts at room temperaturewhich have many special characters such as good stability, high conductivity and wideelectrochemical window, so they have been widely applied in the preparation of newelectrochemical sensors. This thesis focuses on how to manufacture modifiedelectrode, which has high sensitivity and good stability. The author tends to takeadvantage of the merits of ionic liquid and other materials, such as nano materials andpolymers. This research will definitely widen the range of application of ionic liquidin electrochemical analysis and promote the development of modified electrode. Thecontent is as follows:1. Sulfonyl-terminated ionic liquid-stabilized platinum nanoparticlesfor methanol electro-oxidationA sulfonyl-terminated room-temperature ionic liquid,4-(3-methyl-1-imidazolio)-1-butanesulfonic acid triflate (BSMIMOTF), is used as a novel catalyst support.Nafion, a sulfonated cation-exchange polymer, is employed as the conductivemembrane for BSMIMOTF immobilization. Pt nanoparticles (PtNPs) areelectrochemically deposited on BSMIMOTF-Nafion-modified glassy carbon electrode(GCE). The electrocatalytic properties of the electrodes for methanolelectro-oxidation are investigated in detail. Compared with the PtNPs on bare GCsurface, the proposed sulfonyl-terminated ionic liquid-stabilized PtNPs exhibit higherelectrocatalytic activity and better stability toward the electro-oxidation of methanol.The sulfonyl-terminated ionic liquid used as a new catalyst support has great potentialapplications in direct-methanol fuel cells.2. Development of a poly(alizarin red S)/ionic liquid film modifiedelectrode for voltammetric determination of catecholA novel modified electrode for voltammetric catechol determination was fabricated by electroploymerization of alizarin red S (ARS) onto a glassy carbonelectrode (GCE) in one kind of room-temperature ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, BMIMBF4). The polymeric ARS/ionic liquid(PARS/BMIMBF4) film modified electrode was characterized by using scanningelectron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), X-rayphotoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR)and electrochemical methods. The EDX, XPS and FTIR results indicated thatPARS/BMIMBF4film was successfully obtained. Given the combinedelectrochemical activity of PARS and excellent conductivity of BMIMBF4, thePARS/BMIMBF4/GCE has been successfully used for catechol determination bydifferential pulse voltammetry (DPV) with a linear range of0.10to500μmol/L. Thesensitivity and detection limit are42nA/μmol/L and0.026μmol/L, respectively. ThePARS/BMIMBF4modified electrode was successfully applied to the determination ofcatechol in real water samples and may serve as a simple but high-performance sensorfor the determination of some environmental pollutants.3. Room-temperature ionic liquid-nano titanium carbide gelmodified electrode for electrocatalytic oxidation of tryptophanTaking advantage of large specific surface area and strong adsorption property ofnano TiC, as well as the good electrical conductibility and strong electrocatalyticproperty of ionic liquid BMIMPF6, the author grinded Room-temperature ionic liquidBMIMPF6and nano TiC to make gel compound, which was used to modify glassycarbon electrode and applied to the electrochemical determination of tryptophan. Theelectrochemical behavior of tryptophan on the modified electrode was studied indetail by a series of electrochemical characterization. Under the optimal conditions,the oxidation peak current of tryptophan showed a good linear relation with itsconcentration and the detection limit is0.07μmol/L. What’s more, the modifiedelectrode had a certain anti-interference ability and had been successfully applied inthe analysis of the recovery of actual water samples.