可控型態的鉑錫合金奈米線作為有效的甲醇及乙醇氧化反應之電催化劑

Abstract

直接酒精燃料電池（DAFC）是一種對環境友善且高效的能量轉換裝置。本論文主要講述陽極材料Pt3Sn奈米線通過雙功能效應及結構效應來優化，並應用在直接酒精燃料電池上。Pt3Sn奈米線是通過甲酸還原法製備的，並透過場發射式掃描電子顯微鏡 ( FESEM )、穿透式電子顯微鏡 ( TEM ) 、粉末式X光繞射儀 ( XRD )、能量散射光譜儀 ( EDS ) 、X光光電子光譜儀 ( XPS ) 進行物理及化學性質鑑定。活性及穩定性則是使用甲醇氧化反應（MOR）和乙醇氧化反應（EOR）來測試。電化學的結果顯示出雙金屬Pt3Sn觸媒具有比純Pt更好的性能，是因為雙功能機制。奈米線的結構效應顯示出更進一步的增強，藉由通過改變製造過程中的反應物濃度以及反應時間進行優化。以較低濃度製備的樣品(LC-Pt3Sn-144H)需要更長的反應時間才能獲得最長的奈米線，並顯示出最佳的甲/乙醇氧化反應活性和穩定性。高濃度樣品（HC-Pt3Sn-48H）可以顯著的減少製造時間以達到相似的催化劑結構和電化學性能。本論文所設計的觸媒以雙功能機制和結構效應應證，並展示出有效的方法優化製成。

Direct alcohol fuel cells (DAFCs) are environmental friendly and high-efficiency power devices.The present thesis aims to optimize the anodic materials Pt3Sn nanowires (Pt3Sn-NWs) through bifunctional mechanism and structural effects in the application of DAFCs.Pt3Sn NWs are fabricated by formic acidic reduction method and characterized by FE-SEM, TEM, XRD, EDS and XPS to identify their chemical and physical properties. The activity and stability of methanol and ethanol oxidation reactions (MOR and EOR) are further examined. The electrocatalytic results show that bimtallic Pt3Sn catalysts have better performance than pure Pt due to the bifunctional mechanism. The structural effect of NWs shows additional enhancement that can be optimized by varying the concentrations of reagnets and reaction times in the fabrication process. The sample fabricated with lower concentration requires longer reaction time (LC-Pt3Sn-144H) to achieve the highest length of NWs and show the best MOR/EOR activitly and stability. High concentration can significantly reduce the fabrication time (HC-Pt3Sn-48H) to reach the similar catalyst structure and electrochemical performance. The present study demonstrates the design of catalysts through bifunctional mechanism and structural effect, and shows an effective way to optimize the fabrication process.