聚硫氮二烯陸圜-多壁奈米碳管奈米複合修飾電極於NADH電催化及生物燃料電池應用之研究

A Study on Poly(thiazine)-MWCNT Nanocomposite Modified Electrodes and their Applications to NADH Electrocatalysis and Biofuel Cells

王任遠(Jen-Yuan Wang)

指導教授 ： 何國川

共同指導教授 ： 陳林祈(Lin-Chi Chen)

國立臺灣大學/工學院/高分子科學與工程學研究所/碩士(2008年)

https://doi.org/10.6342/NTU.2008.10063

摘要

菸鹼醯胺核甘酸（β-nicotinamide adenine dinucleotide，以下略稱NADH）為脫氫酵素（dehydrogenase）之輔酉每（coenzyme），在新陳代謝過程（metabolism）中扮演著不可缺少的關鍵生化物質。在生物界中有四百多種脫氫酵素在進行生化反應時，皆必須透過NADH做為反應之媒介物。也因此NADH在生化領域的應用廣泛，無論是酵素型感測器或是生物反應器等生物元件中均可現其蹤跡。在這些研究當中，NADH催化反應一直是脫氫酵素系統操作程序的關鍵所在，而催化方式可分為直接電催化與間接電催化。在過去的研究中發現以惰性電極對NADH直接進行催化反應所需之過電位通常很高；為了減少能量的消耗，利用媒介分子催化劑間接催化NADH為較理想之對策。然而媒介分子亦分為酵素型（例如diaphorase）與非酵素型（例如酉昆，quinone），基於生物界長久以來的演化，傳統上使用酵素型媒介分子進行NADH電催化具有高電子轉移效率；但是必須加入第二種還原物基質、酵素純化步驟繁雜或售價昂貴且穩定性不佳阻礙了相關生物元件之發展進度。因此本研究應用導電高分子奈米複合材料提升NADH電催化效率，同時期望藉以製備高穩定之NADH催化電極並將之應用於生物電子元件系統。
本研究主要分成三大部分，首先我們分別以亞甲基藍以及亞甲基綠為單體，利用電化學聚合法（electrochemical polymerization）在多壁奈米碳管修飾（multi-walled carbon nanotube）之網印碳電極上形成一導電高分子奈米複合薄膜，分析並比較在經過奈米碳管修飾前後，電極在電化學特性之變化。此部分實驗可發現，poly(methylene blue)與poly(methylene green)薄膜在經過多壁奈米碳管修飾之電極表面上，均可產生較完整之聚合結構與較穩定的電化學活性。
接著在第二部分，我們利用上述之導電高分子奈米複合修飾電極進行對NADH電催化測試，並探究多壁奈米碳管於此催化反應中之影響及比較各電極製程對於NADH電催化反應之差異。在電流式NADH感測實驗中我們觀察到，與未修飾的導電高分子電極相較，經過奈米碳管修飾之電極都具有較高之靈敏度，而其中又以MWCNT-poly(methylene blue)組合之修飾電極的靈敏度最高（58.75 μA mM-1 cm-2）。
最後，我們以MWCNT-poly(methylene blue)奈米複合電極做為生物陽極，分別應用於酒精及葡萄糖生物燃料電池系統，藉以改進NADH催化反應進而提升燃料電池之效能。在比較燃料電池輸出功率後，我們証實利用MWCNT-poly(methylene blue)奈米複合材料可有效提高生物燃料電池之效能，在酒精生物燃料電池系統中，輸出功率由1.8 μW cm-2提升至2.76 μW cm-2。而葡萄糖生物燃料電池系統由2.32 μW cm-2提升至10.5 μW cm-2；在進一步對電極製程改進後可達24.25 μW cm-2。

關鍵字

菸鹼醯胺核 ； 脫氫酵素 ； 酒精生物燃料電池 ； 葡萄糖生物燃料電池 ； 多壁奈米碳管 ； 聚亞甲基藍 ； 聚亞甲基綠

並列摘要

β-nicotinamide adenine dinucleotide (NADH), the reduced form of nicotinamide adenine dinucleotide(NAD+), is an important coenzyme of dehydrogenases. It plays key biochemical roles in transferring protons and electrons in the metabolic reactions carried out by over 400 dehydrogenases. The direct oxidation of NADH on a bare inert electrode is slow and unobvious due to high overpotentials. Therefore, using enzymatic or electrochemical catalysts to decrease the overpotential has been a proper method. Traditionally, the use of a second enzyme can guarantee the NAD+ (such as diaphorase) formation in natural regenerations. However, the complex procedures of purification and high cost and instability of enzyme become another issues. In this work, a screen printing carbon electrode (SPCE) modified with multi-walled carbon nanotube (MWCNT) and poly(thiazine) was used to enhance the electrocatalytic NADH oxidation for bioelectronic device applications.
This thesis consists of three parts. In the first part of this research, we used methylene blue and methylene green as the monomers and prepared a MWCNT-poly(thiazine) nanocomposite film on the SPCE by electrochemical polymerization. By carrying out basic electrochemical analyses, it was found that the MWCNT-poly(thiazine) nanocomposite has a better polymer structure, thus performs better in cycling stability.
In the second part, we used amperometric NADH detection to obtain the efficiency of NADH electrocatalysis of the MWCNT-poly(thiazine) nanocomposite. It was found that the MWCNT-poly(thiazine) nanocomposite could achieve preeminent improvement in NADH catalytic efficiency as compared to a bare poly(thiazine) modified SPCE. As for the MWCNT/PMB electrode, the sensitivity was increased from 0.58 μA mM-1cm-2 (PMB) to 38.95 μA mM-1cm-2 (MWCNT/PMB).
Finally, the MWCNT-PMB nanocomposite electrode was used as a bioanode and applied to an ethanol biofuel cell and a glucose biofuel cell, respectively. The preliminary experiments indicated that the MWCNT-PMB nanocomposite could enhance the power density of these biofuel cell systems. For the ethanol biofuel cell, the power density was increased from 1.8 to 2.76 μW cm-2. The glucose biofuel cell could achieve 10.5 μW cm-2 with the modification of the MWCNT-PMB nanocomposite. After further improvement for electrode preparation, the glucose biofuel cell could perform an efficiency as high as 24.25 μW cm-2.

並列關鍵字

β-nicotinamide adenine dinucleotide ； dehydrogenase ； ethanol biofuel cell ； glucose biofuel cell ； multi-walled carbon nanotube ； poly(methylene blue) ； poly(methylene green).

參考文獻

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