| The Room temperature ionic liquids (RTILs), composed of organic cation and inorganic anion, are widely used as solvent in the field of synthesis and electrochemistry. These compounds have excellent properties because of their particular structures which attract significant attention in the electrochemical areas. There is difference between the interface of ionic liquid/metal and classical electrochemical system. Therefore, the investigation on the structure at ionic liquid/metal interface is necessary for extending the application of ionic liquids. The Surface enhanced Raman spectroscopy (SERS) with extremely high surface sensitivity combined with electrochemical methods might be developed as powerful tool to probe the interface structure at molecular level. The main results are as follows:1. The electrochemistry properties of RTILs with different anions have been investigated at the different electrodes by electrochemical CV method. Combining with SERS, the potential dependent adsorption behavior of hydrophilic and hydrophobic RTILs was studied at Ag electrode. At relative positive potential (positive than pzc), the imidazolium ring nearly perpendicular to the surface, and the imidazolium ring stays almost parallel to the surface at potentials negative to pzc. At extremely negative potential, the cation of BMIM+ is reduced to the BMIM carbene.2. The effect of water on the orientation of ionic liquids on the electrode surface has been investigated using electrochemical SERS, the adsorption behavior and interface structure of water with different molar fraction was determined in ionic liquids. The results showed that the cations and anions in ionic liquids interacted with water through hydrogen bonding. When the ratio of water up to 0.7, the water molecular tended to organized in"network". The observation of different O-H stretching vibration indicated the various configuration of water in ionic liquids. The configuration of water in the ionic liquids is influenced by the types of anions and water content.3. The adsorption behavior of thiocyanate(SCN-) at the Pt electrode in the RTILs based on 1-butyl-3-methylimidazolim cation has been determined using in-situ SERS. Preliminary results demonstrated that the SERS signal of SCN- can be detected in a wider potential region, and the adsorption behavior of SCN- changed along with the potential. Different Stark effects were observed in different potential regions, which can deduce the pzc of the ionic liquid/Pt system. The frequency of C-N is related to the anions of ionic liquids.
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