離子液體內以伽凡尼置換法製備鎳鋅奈米線纏繞形成之孔洞結構的研究及用於尿素電催化氧化之應用

Study of the Formation of Tangled NiZn Nanowire-Composed Porous Structure via Galvanic Replacement in Ionic Liquids and Application in Electrocatalytic Urea Oxidation

陳薏婷(Yi-Ting Chen)

指導教授 ： 陳泊余

高雄醫學大學/生命科學院/醫藥暨應用化學系碩士班/碩士(2019年)

摘要

本研究於含ZnCl2及NiCl2的1-butyl-1-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (BMP-TFSA)離子液體中探討Zn(II)及Ni(II)離子的電化學行為。於含0.2 M ZnCl2的BMP-TFSA離子液體中電沉積具有奈米線交錯而成之孔洞鋅電極(SSE n)，並以此作為犧牲模板於含Ni(II)離子的BMP-TFSA離子液體中進行伽凡尼置換反應(galvanic replacement)，探討置換時間、溫度及濃度對反應的影響，最後成功得到具奈米線纏繞而成的孔洞鎳鋅合金電極(SSENiZn)，並藉由掃描式電子顯微鏡(SEM)和元素半定量分析(EDX)觀察其鍍層的表面型態與組成比例。該電極應用於尿素電催化氧化反應及尿素偵測分析，結果顯示其具有良好的穩定性、耐受性、靈敏度(902.8 μA·mM-1·cm-2)及寬廣的線性範圍(1 μM-20 mM)，偵測極限達3 μM。於真實水樣中進行尿素回收率測試，偵測低濃度(100 μM)之回收率在85%-96%之間。最後，本研究顯示水溶液及深共熔溶劑無法成功維持犧牲模版形貌置換出NiZn電極，顯示出離子液體的優勢。然而，離子液體的組成陽離子對能否維持形貌影響甚大。本研究亦初步嘗試於BMP-TFSA離子液體中進行Cu的置換，其結構雖不似置換Ni時的完美，但經優化後此系統應能成功置換其它金屬甚或合金。

關鍵字

離子液體 ； 電沉積 ； 伽凡尼置換 ； 尿素催化 ； 鎳電極 ； 鋅奈米線

並列摘要

In this study, the electrochemical behavior of ZnCl2 and NiCl2 was investigated in ionic liquid 1-butyl-1-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)amide (BMP-TFSA). Electrodeposition of curved Zn nanowires-composed porous structure was conducted on stainless-steel electrodes (SSE n) at selected temperatures and potentials from BMP-TFSA with 0.2 M ZnCl2.to be the sacrificial templates for the preparation of Ni and/or NiZn alloy electrodes (SSENiZn) via galvanic replacement in ionic liquids containing Ni(II) species. NixZny electrodes with various Ni/Zn atomic ratios were prepared, and the effects of replacement temperatures, time durations, and concentrations of Ni(II) on the Ni/Zn ratios were studied. The scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to characterize the surface morphology and the elemental compositions of the obtained Zn and NiZn electrodes. The SSENiZn was used as catalytic electrodes for the electrooxidation and detection of urea, respectively The results showed that SSENiZn exhibited a good catalytic activity, electrochemical durability, and high sensitivity (902.8 μA·mM-1·cm-2) for urea detection in the linear concentration range of 1 μM-20 mM; the limit of detection was 3 μM. Moreover, the recovery test conducted in real samples showed the recovery ratios between 85% and 96% for 100 μM of urea. We also attempted to prepare SSENiZn via galvanic replacement in several solvent systems, such as aqueous solution and deep eutectic solvent. No successful result was obtained, indicating the superiority of ionic liquid on galvanic replacement. However, the cation of the ionic liquid seemed to play a crucial role in the successful galvanic replacement.
In the last experiment, galvanic replacement of Cu was attempted to prepare CuZn alloy electrodes in BMP-TFSA. The preliminary results indicated that wire-composed porous structure of SSECuZn could be obtained but they were something different from the SSENiZn structures although the EDX showed the high content of Cu in the CuZn alloy. This study indicated that ionic liquid is a superior solvent for galvanic replacement, and galvanic replacement is a simple method for preparing metal alloy electrodes that can retain the original structure of the sacrificial template.

並列關鍵字

Ionic liquid ； Electrodeposition ； Galvanic replacement ； Urea catalysis ； Nickel electrode ； Zinc nanowire

參考文獻

1. Walden, P., Über die Molekulargrösse und elektrische Leitfähigkeit einiger geschmolzener Salze. Bulletin del'Académie Impériale des Sciences de St.-Pétersbourg. 1914, 8 (6), 405-422.

2. Smith, E. L.; Abbott, A. P.; Ryder, K. S., Deep eutectic solvents (DESs) and their applications. Chemical reviews 2014, 114 (21), 11060-11082.

3. Jaeger, D. A.; Tucker, C. E., Diels-Alder reactions in ethylammonium nitrate, a low-melting fused salt. Tetrahedron Letters 1989, 30 (14), 1785-1788.

4. Knifton, J. F., Ethylene Glycol from Synthesis Gas via Ruthenium Melt Catalysis. Journal of the American Chemical Society 1981, 103, 3959-3961.

5. Chauvin, Y.; Gilbert, B.; Guibard, I., Catalytic dimerization of alkenes by nickel complexes in organochloroaluminate molten salts. Journal of the Chemical Society, Chemical Communications 1990, (23), 1715.