| Summary: | 博士 === 國立成功大學 === 化學系碩博士班 === 94 === Abstract
In recent years, ambient temperature ionic liquids have drawn enormous attention due to their attractive properties including negligible vapor pressure, high thermal and chemical stability, and high conductivity. Consequently, ionic liquids have been described as “green” solvents in place of molecular organic solvents for organic synthesis, separation, and electrochemical applications. The most well known ionic liquid system is the one consisting aluminum chloride anion and certain dialkylimidazolium cations. Although the aluminum chloride based ionic liquids have found wide applications, they are highly moisture/air-sensitive. This problem is circumvented by replacing the aluminum chloride anion with other anions to produce ionic liquids that are water/air-stable.
In this thesis, we have reported the new low temperature ionic liquids result from the combination of zinc chloride and 1-ethyl-3-methylimidazolium chloride. The main content is concentrated in the characterization and applications of this melt. We found this melt is also an air and water stable ionic liquid due to ZnCl2 is insensitive to the air and moisture and the acidic melt are potentially useful for the electrodeposition of zinc and zinc-containing alloys. The preparation of zinc and zinc-containing alloys coatings, including ZnSn, ZnFe, and PtZn alloys, has been conduct with this melt. The main advantage are eliminating the challenge of hydrogen evolution and the anomalous co-deposition behavior
The application of this melt is extended to the fabrication of advanced materials, eq. nanoporous noble metals. A simple electrochemical strategy is described to prepare high surface area nanostructured platinum and gold electrode by alloying and dealloying of MZn (M = Pt or Au) in a Lewis acidic ZnCl2-EMIC ionic liquid. Some of the general advantages of the method include (1) the nano-size can be manipulated by varying the quantity of MZn surface alloy through the electrodeposition charge, (2) no corrosive acids or bases were used for the dealloying, (3) extremely high working temperature is not required, and (4) applicability to any other system that forms surface alloy with Zn. The resulting nanoporous Pt electrode showed significantly enhanced current for hydrogen and methanol redox reactions. The nanoporous Au surface could be functionalized with SAMs of L-cysteine and the potential utility of the modified nanoporous Au for sensors was demonstrated by its excellent sensitivity and selectivity for the electrochemical determination of Cu(II).
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