氧化物奈米結構在過氧化氫檢測上之應用

Applications of Oxide Nanostructure on Sensing Hydrogen Peroxide

柳岱旼(Tai-Min Liu)

指導教授 ： 呂世源

國立清華大學/工學院/化學工程學系/碩士(2015年)

摘要

回顧過去許多進行生物感測器的文獻，發現大部分的研究，使用玻璃碳電極(GCE)來做為生物感測器之電極使用，因為操作簡單，可以很容易的將所需研究之觸媒材料，快速滴至GCE電極表面，進行感測活性之測試。因此本研究認為要做為一個理想的生物感測器電極，除了需選用適當的觸媒材料外，有效地將電極進行結構修飾，使觸媒與感測器電極表面間，所形成交界表面形貌，增加其表面積與電子傳遞，勢必能提升其感測效果，更是值得討論的重點。電極表面需具備優異的導電性，將感測反應所產生之電子訊號，快速的導出，並藉由電極表面良好的親水性與高結構表面積，增加與目標待測物接觸的機會。本研究使用過去所發展的電化學表面修飾技術，成功改善市售透明導電玻璃，其親水性與結構表面積不足的問題，提供一個未來取代玻璃碳電極之電極選擇。
本研究分兩部分進行，第一部分藉過去所發展的電化學表面修飾技術，針對市售透明導電玻璃之表面形貌，進行更深入的研究與討論，以製備出具優異導電性與親水性之多孔洞FTO電極。研究過程發現，於0.07 M SnCl4‧H2O製程濃度下，所製備的表面孔洞結構最為完整，相較於市售FTO玻璃，其粗糙度可從18 nm增加到36 nm左右，接觸角自36.1o下降至4.4o，大幅提升電極表面之親水性，而片電阻值約17.1Ω□-1，仍屬高導電性的規格範圍內。於電化學生物感測實驗部分，選用大家所熟知，針對H2O2具有優異催化分解之Pt貴金屬，負載至多孔洞FTO電極表面，來做為展現其高結構表面積的優勢，相較於市售FTO玻璃，測試結果顯示，孔洞結構越完整之FTO電極，能附著較多且較均勻之Pt顆粒表面形貌，優異的H2O2感測效能(25.8 mA/Mcm2)，甚至高於市售FTO玻璃(2.68 mA/Mcm2)的10倍。

第二部分研究重點，乃利用實驗室過去所開發之界面合成反應法，進行合成一具高催化活性且可取代Pt貴金屬之尖金石氧化物結構，錫鐵氧化物(SnFe2O4)。研究過程發現，使用1.0 M NaOH濃度所製備之錫鐵氧化物，負載至多孔洞FTO電極表面，可獲得具良好的親水性之接觸角4.68o，於 H2O2感測器效果表現，靈敏度高達1027 mA/Mcm2。於過去2005至2015年間，比較使用ITO或FTO做為電化學感測器之電極研究，發現我們所獲得的靈敏度是最高的，甚至可與過去文獻，使用 Pt貴金屬做為觸媒，負載至GCE電極上之感測靈敏度結果，並駕齊驅，由此更加證明，我們所製備之高催化活性之SnFe2O4，具有相當大的潛力，於未來有很大機會能取代Pt貴金屬，成為新一代電化學H2O2生物感測器之電極材料。

關鍵字

過氧化氫 ； 感測器 ； 錫鐵氧化物 ； 尖晶石 ； 鉑金屬

並列摘要

Many researches about biosensors have used Glass Carbon Electrode (GCE) as the host electrode for sensing catalysts, because it is easy to drop the catalysts onto the GCE and used it for sensing. If we want to make an ideal sensor electrode, the most important thing is to choose not only the appropriate catalysts but also the host electrode. Host electrodes need good electric conductivities to rapidly transfer the electronic signals, produced by the sensing reaction. With good hydrophilicity and high interficial areas, the host electrode can enhance the contact with the target components. In this study, we utilized a previously developed technique to modify commercial FTO glass, and improved on the low hydrophilicity and interficial areas of the commercial FTO, providing a choice of substitution for the GCE.
In the first part of this study, we used a simple electrochemical treatment to modify the commercial FTO glass. After a series of fabrications, we produced porous FTO with an extraordinary conductivity and good hydrophilicity as we concocted the concentration of SnCl4‧H2O to 0.07 M. A well-developed porous structure was acquired. Comparing to the commercial FTO, the porous FTO possessed high porosities and the roughness was enhanced to 18~36 nm. The static contact angle dropped from 36.1 to 4.4o, and the sheet resistance was about 17.1 Ω□-1. We proceeded with the electrochemical sensing for applications in H2O2 sensing through Pt-loading. As a result, the high porosity enabled a uniform distribution of Pt nanoparticles on the FTO pore surface. The porous FTO was good for Pt loading. This sample showed a high sensitivity of 25.8 mA/Mcm2, ten times of that of the commercial FTO (2.68 mA/Mcm2).
For the second part of the study, by using a one-step carrier solvent assisted interfacial reaction process, we successfully synthesized SnFe2O4 nanocrystals, intended for the replacement of Pt. In the experiment, we adjusted the concentration of NaOH to 1M, so that we can obtain SnFe2O4 nanocrystals, which can catalyze reduction of H2O2. After loading it to the porous FTO electrode surface, the static contact angle is about 4.68o, the sensitivity of sensing H2O2 was up to 1027 mA/Mcm2, which is much higher than most of the number indicated by the references using Pt with FTO and ITO, and GCE as the sensing electrode over the past ten years. But comparing to Pt, SnFe2O4 is not toxic and much cheaper. So this study successfully develops a promising and novel nanomaterial, which is an excellent catalyst, and has a good potential to replace Pt as the sensing catalyst.

並列關鍵字

Hydrogen peroxide ； sensor ； SnFe2O4 ； spinel ； Pt ； FTO

參考文獻

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