Synthesis of highly dispersed Pt electrocatalyst and its applications in PEMFC and VRFB

對於電池而言，電極是電池工作產生電力的基本原件，對於燃料電池電極而言，電極觸媒更是電極發生化學反應轉換電能的重要角色，觸媒扮演著燃料的氧化與還原的催化劑，電極的結構與狀態是整個電池發生電化學反應的場所，因此擔載觸媒的多孔隙結構與觸媒的分散狀態相對於在質子交換膜燃料電池工作過程中，無疑的，觸媒的效能左右著整個質子交換膜燃料電池的效率與穩定性，由此，製備高分散與高效能的電極觸媒將成為關鍵性要素。在此論文中，高分散的Pt觸媒製備技術是使用化學含浸還原法搭配熱回流裝置，使用容易取得的陽離子型界面活性劑(CTAB) 十六烷基三甲基溴化銨，當分散劑，最後使用低溫高壓熱鍜燒技術清除劑面活性劑，使得Pt 奈米觸媒能夠發揮其最佳功效。 本論文包含兩個子主題，其涵蓋了Pt奈米材料製程、材料的物理分析與電化學分析，進一步的應用於質子交換膜燃料電池與全釩液流儲能電池系統。第一個子主題著重於高分散性的鉑/碳黑奈米電極觸媒粒子製備與開發，並應用於質子交換膜電池當其高效能的電極觸媒。電極觸媒粒子的製備上使用傳統的含浸法搭配陽離子型界面活性劑(CTAB)當碳黑與鉑金的分散劑，針對三種不同濃度的界面活性劑4.12×10-2 M、2.75×10-2 M 與1.37×10-2 M輔助製備高分散性的鉑奈米粒子，再利用新開發的低溫高壓鍜燒技術移除界面活性劑，讓鉑奈米粒子能夠在高分散狀態展現其最佳效能。隨著使用分散劑量的增加，透過穿透式電子顯微鏡的觀察，鉑奈米粒子的粒徑由2.3 nm，2.5 nm，2.7 nm隨之增大，且均勻的被分散於碳黑上，進一步的利用電化學技術來分析本製程製備的鉑電極觸媒的活性面積與效能並與目前商用的電極觸媒作善意的比較，本實驗製程所製備的鉑電極觸媒，其最佳效能高出商用觸媒約13%，其處於在甲醇與硫酸混合電解液的環境下也與商用觸媒具有相當穩定的性質。經由等量的鉑觸媒塗層，單電池測試結果顯示，於常溫25 ◦C 與高溫75 ◦C下，鉑觸媒Pt/C-4.12 (Pt size=2.7 nm)所製備的膜電極MEA-1具有最佳的電池效能，並且在25 ◦C與75 ◦C兩個操作溫度下，電池效能分別高出商用的40.9% 與45.4%，此意味著本製程所製備的鉑觸媒極具應用於質子交換膜燃料電池系統的潛力。第二個子主題則著重於使用第一主題所開發的高分散性Pt電極觸媒分散技術製備高效能的奈米鉑/多壁奈米碳管電極觸媒，並嘗試的應用於全釩液流儲能電池系統中，探討當其活性電極觸媒層的可能性。於電化學分析中發現使用鉑電極於含有四價釩的硫酸溶液中可促進四價釩與三價釩的氧化還原對發生及可促進四價釩與五價釩的氧化還原電流的提升，並進一步的將高效能的奈米鉑/多壁奈米碳管電極觸媒使用於全釩電池系統中，將奈米鉑/多壁奈米碳管電極觸媒設計塗層於陰極活性電極層上當活性觸媒層，並於陰陽兩極均使用相同的含有四價釩的硫酸電解液進行充放電測試，發現此設計形成三價釩/五價釩的氧化還原液流電池，同時也印證了電化學分析中的四價釩與三價釩的氧化 還原反應的存在。相反的，在相同的實驗條件下，純碳的活性電極則無此功能。另將奈米鉑/多壁奈米碳管電極觸媒塗層於陽極活性電極層上當活性觸媒層使用於傳統的二價釩/五價釩的氧化還液流電池中，很明顯的有使用觸媒的全釩電池效能比沒使用的電池高出約8%，由上述兩項使用鉑活性觸媒結果可知，在全釩液流電池系統中使用鉑活性觸媒層是可行，然而這在於經濟效益的考量上似乎也是一大考驗，期許於未來的研究上能夠找尋出的低價位的活性金屬觸媒來促進全釩液流電池效能上的提升。 由以上兩個子主題結果可得知，一個良好的分散技術可讓高分散的鉑觸媒發揮其最大的功效，並且可廣泛的應用於使用鉑當觸媒的能源領域。An electrode is a basic device that generates battery power. Platinum electrocatalysts assist in the redox reaction of fuels for proton exchange membrane (PEM) fuel cells in separated electrodes. When a membrane electrode assembly is combined with porous electrocatalyst support, high dispersal of Pt catalyst and membrane, the performance and the durability of catalysts substantially affect the capacity, efficiency, and the stability of PEM fuel cells. The preparation of the high dispersal and performance of a Pt/C catalyst is a key factor in good cell performance. In this dissertation, the high dispersal of a Pt/C and a Pt/MWNT electrode catalyst was synthesized with a reflux device by impregnation method. The commercially and readily available cationic surfactant cetyltrimethylammonium bromide (CTAB) was used as dispersant. The low temperature and the high vacuum pressure of calcination removed the CTAB, and the performance of the Pt catalyst was improved. The dissertation focuses on the topics of Pt material synthesis, nanotechnology, physical and electrochemical characteristics of Pt material, and application of Pt electrocatalyst material to the proton exchange membrane (PEM) fuel cell and the vanadium redox flow battery (VRFB) system. The first objective of this dissertation is to prepare the high dispersion of a Pt electrocatalyst to improve its efficiency and hence enhance the performance of PEM fuel cells. As a dispersant, CTAB has three concentrations (4.12×10-2, 2.75×10-2, and 1.37×10-2 M) that are necessary in the preparation of the high dispersal of Pt/C electrocatalysts (Pt/C-4.12, Pt/C-2.75, and Pt/C-1.37) via calcination to remove the CTAB and hence obtain good performance of the Pt/C catalyst. In this study, transmission electron microscopy analysis showed that the average size of the Pt nanoparticles slightly increased from 2.3 nm to 2.7 nm with an increase in the quantity of CTAB added, and the Pt nanoparticle on the surface of carbon black (XC-72) was successfully reduced. The best Pt utilization efficiency of Pt/C-4.12 was 63.53%, which was 13.16 % higher than that of the commercial catalyst JM-20 wt% Pt/C. Under the electrolyte of CH3OH + H2SO4, the durability of the in-house Pt/C catalyst was as good as that of the commercial catalyst. Furthermore, the polarization curve test of the single cell MEA-1 with the Pt/C-4.12 catalyst had the highest power density among all MEAs. At 25 °C, the high power density of MEA-1 (0.937 W cm-2 mg-1) was 40.9% higher than that of MEA-JM. At 75 °C, and the maximum power density of MEA-1 was 45.4% higher than that of the commercial one. These results imply that the significant electrocatalytic capability of the synthesized Pt/C catalyst obtained through this procedure can be exploited in a fuel cell environment. The second objective of this dissertation is to examine the feasibility of the highly active Pt/MWNT electrocatalyst as an active catalyst layer (CL) applied in the VRFB system. The high activity of the Pt/MWNT electrocatalyst was prepared by first object technology. Cyclic voltammetry analyses demonstrated that the Pt/MWNT electrocatalyst has good performance in enhancing V3+/VO2+ and VO2+/VO2+ redox reactions under 0.01 M VOSO4 + 0.2 M H2SO4 electrolyte. Ion diffusion was suggested to control the redox reaction behavior of V3+/VO2+ and VO2+/VO2+ on each electrode. During the charge–discharge test of a single cell, no catalyst existed in the positive end, and both active electrodes used the same electrolyte (1 M VO2+ –1 M H2SO4) when the activity CL of the Pt/MWNT electrocatalyst was designed in the negative electrode. The redox reaction of V3+/VO2+ occurred in the cathode, whereas the redox reaction of VO2+/VO2+ occurred in the anode, a result indicating the redox coupling of V3+/VO2+ and the simultaneous establishment of a new type of V(III)/V(V) battery. Under the same experimental parameter and system, the charge–discharge function of a single cell will not be presented with the pristine active carbon material of both electrodes. Moreover, when the Pt/MWNT electrocatalyst layer was set in the positive active electrode (Pt/MWNT + GF) and the negative active electrode was pristine graphite felt, and when 1 M VO2+ + 1 M H2SO4 solution was used on the positive side and 1 M V3+ + 1 M H2SO4 solution was used on the negative side. The performance of the traditional V(II)/V(V) single cell obviously improved by 11.58% and 8% with the Pt/MWNT electrocatalyst layer compared with that using pristine graphite felt as active electrode at the two operating current densities of 20 and 30 mA cm-2, respectively. On the basis of these results, the Pt active catalyst improves the potential of the VRFB system. Nevertheless, the cost-effectiveness of the use of novel Pt metal as an active CL in the VRFB system is required. Therefore, this study also aims to discover a low-cost active metal catalyst to improve the performance of VRFB further.Contents Acknowledgement……………………………………………………………………i Abstract (Chinese)…………………………………………………………………..ii Abstract (English)…………………………………………………………………..iv Contents……………………………………………………………………………vii List of tables………………………………………………………………………...x List of Figures………………………………………………………………………..xi Chapter 1 Background……………………………………………………………….1 1-1 Development of Fuel Cell……………………………………………………1 1-1-1 Classification of Fuel Cell…………………………………………………4 1-1-2 Principle of PEMFC……………………………………………………….7 1-1-3 Constructions of PEMFC…………………………………………………..9 1-1-3.1 Gas diffusion layer (GDL)……………………………………………..9 1-1-3.2 Catalyst layer (CL)…………………………………………………...10 1-1-3.3 Polymer Electrolyte membrane (PEM)……………………………….11 1-1-4 Polarization curve of PEMFC…………………………………………….13 1-2 Development of Vanadium Redox Flow Battery……….…………..15 1-2-1 Classification of various redox flow batteries……………………………17 1-2-1-(a) Iron/chromium redox flow battery…………………………………17 1-2-1-(b) Polysulphide Sodium/Bromine redox flow battery………………..18 1-2-1-(c) Bromine-vanadium redox flow battery…………………………….20 1-2-1-(d) Vanadium/Vanadium redox flow battery…………………………..21 1-2-1-(e) Zinc/cerium redox flow cells………………………………………22 1-2-1-(f) Soluble lead-acid flow battery……………………………………..23 1-2-2 Principle and construction of the vanadium redox flow battery…………24 1-2-3 Charge-discharge curve of VRB system………………………………26 1-2-4 Advantage of vanadium redox flow battery………………………28 1-3 Motivation and objective…………………………………………………...30 Reference………………………………………………………………………...32 Chapter 2 Synthesis of highly dispersed Platinum/carbon catalyst using cetyltrimethyl ammonium bromide as a dispersant for proton exchange membrane fuel cells……………………………………….40 Abstract …………………………………………………………………………..40 2-1 Introduction……………………………………………………………...41 2-2 Experimental…………………………………………………………….43 2-2-1 Preparation of the Pt/C catalyst…………………………………………..43 2-2-2 Physicochemical characterization of the Pt/C catalyst…………………...44 2-2-3 Measurement of polarization curves……………………………………...45 2-3 Results and Discussion…………………………………………………..46 2-3-1 Characterization of the Pt/C catalyst……………………………………..46 2-3-2 Pt content in the Pt/C catalyst…………………………………………….57 2-3-3 Electrochemical characterization of the Pt/C catalyst……………………59 2-3-4 Single cell polarization test……………………………………………….63 2-4 Summary…………………………………………………………………..67 Reference………………………………………………………………………….68 Chapter 3 Investigation of active electrodes modified with platinum/multiwalled carbon nanotube for vanadium redox flow battery…………………..70 Abstract …………………………………………………………………………..70 3-1 Introduction……………………………………………………………..71 3-2 Experimental…………………………………………………………….73 3-2-1 Preparation of the Pt/MWNT electrocatalyst…………………………….73 3-2-2 Characterization measurements of the Pt/MWNT electrocatalyst……….73 3-2-3 Electrochemical characteristics of the Pt/MWNTs, MWNTs, and commercial electrocatalysts in vanadic sulfuric acid electrolyte………...74 3-2-4 Battery fabrication and charge-discharge measurements of VRFB………...75 3-3 Results and Discussion………………………………………………….77 3-3-1 Physicochemical characteristics of the Pt/MWNT electrode material….......77 3-3-2 Electrochemical characterization of the Pt/MWNT and commercial electrocatalyst in sulfuric acid electrolyte………………………………….82 3-3-3 Electrochemical characterization of the Pt/MWNTs, JM-Pt/C, and MWNTs in vanadic sulfuric acid electrolyte………………………………………83 3-3-4 Charge-discharge experiments of the V(III)/V(V) single cell …………...92 3-3-5 Charge-discharge experiments of the V(II)/V(V) single cell…………….94 3-4 Summary…………………………………………………………………...100 Reference…………………………………………………………………………..101 Chapter 4 Conclusion…………………………………………………………104 Abbreviation……………………………………………………………………….107 Vita and Publications List…………………………………………………………10

Design and implementation of high temperature superconducting (HTS) tape RF coil and cryostat for MRI applications

published_or_final_versionabstractElectrical and Electronic EngineeringMasterMaster of Philosoph

Preparation of well-dispersed Pt/C electrocatalyst for proton exchange membrane fuel cells

中文摘要 質子交換膜燃料電池（PEMFC）具有高能量密度、高轉換效率、操作容易和零污染等優點，因此備受各界矚目。為提升鉑(Pt)觸媒的使用率及降低使用貴重金屬Pt的成本，如能使碳材載體具有高表面積和鉑(Pt)觸媒能夠高度分散於碳載體上，應用於燃料電池電極觸媒中，則電池效能將有效的提升。 本研究探討陽離子型界面活性劑(CTABr)當鉑(Pt)與碳黑(C)之分散劑輔以熱迴流法備製鉑/碳黑（Pt/C）觸媒，針對不同濃度的陽離子型界面活性劑(CTABr)所備製之電極觸媒，透過X-ray繞射儀(XRD)、場發射掃描式電子顯微鏡、穿透式電子顯微鏡、電化學分析儀(CV)、氣體吸脫附分析儀(BET)、熱重/熱差分析儀(TG/DTA)、感應耦合電漿質譜儀(ICP-MS)、雷射粒徑分析儀(DLS)等儀器，分析觸媒晶體結構、成份、比重、熱穩定度、Pt粒子的尺寸和在載體上的分散程度以及觸媒的活性面積。探討不同濃度所分散之電極觸媒對於燃料電池效能之影響，並且依不同重量百分比（18% Pt/C 、15% Pt/C和10% Pt/C）之鉑/碳黑（Pt/C）電極觸媒，與(Johnson Matthey)商用電極觸媒20% Pt/C進行電池效能分析。 研究結果發現以陽離子型界面活性劑(CTABr)當分散劑，所製備的鉑/碳黑觸媒之鉑粒子尺寸、分散程度與觸媒活性面積都比商用觸媒較佳，其鉑粒子依不同(CTABr)分散濃度所製備之粒徑分別為{4.12mM/L(2.2~4.16nm、2.75mM/L(1.5~3.92nm)和1.37 mM/L(1.4~5.66nm)）}，從TEM&SEM圖可很明顯看出Pt 粒徑隨著分散劑濃度的增加而增大，由BET所測試出的Pt/C觸媒整體表面積分別為(Johnson Matthey)商用電極觸媒20%Pt/C 23.518 ，{18% Pt/C (35.904 )和15% Pt/C (27.995 ) }。經實驗證實，以Pt loading 0.4 mg/cm 的單電池測試上，發現自備製之Pt/C觸媒，電池效能隨著Pt 濃度的增加而增強18 wt. % > 15 wt. % > 10 wt. %.且所有的電池效能均比使用商用觸媒的電池優。由此可見以陽離子型界面活性劑(CTABr)當分散劑是很有效率的分散碳黑及Pt粒子，更是有效的提升整個電池效能。Proton exchange membrane fuel cells (PEMFCs) have been regarded as a candidate for future power sources for transport, residential and portable applications, primarily due to the advantageous characteristics of high power density, high energy-conversion, simplicity of operation and near-zero pollutant emission. For commercialization, the high surface area carbon carriers, such as carbon black and carbon nanotube, were widely used in PEMFC for enhancing the utility of the Pt catalyst and reducing the prime cost caused by the expenditure of Pt . In this study, the Pt/C catalysts were synthesized by using the cationic surfactant (CTABr) as dispersant to disperse carbon black via thermal reflux method. For investigating the composition and the area of active sites of the catalyst, the particle size of Pt. nano-particles and the effect caused by the different CTABr-added concentration, several techniques, such as X-ray diffraction instrument (XRD), Field emission scanning electron microscope(FESEM), Transmission electron microscope (TEM), Brunauer-Emmett-Tellerand (BET) , TG/DTA, DLS,and chemical analyzer (CV), were hired. Furthermore the cell performance of homemade Pt/C catalyst with different concentration of Pt (18 wt. %, 15 wt. % and 10 wt. %) were compared with commercial Pt/C catalyst with 20 wt. % Pt (Johnson Matthey) to explore the influence on cell performance arised from different Pt concentration. As the result, the particle size of Pt nano-particles were smaller than that of commercial catalyst (Johnson Matthey) and the dispersion degree Pt and the active area of the homemade Pt/C catalyst were higher that of commercial catalyst (Johnson Matthey) as well, by using cationic surfactant (CTABr) as dispersant in the preparation of Pt/C electrocatalyst. The particle size of Pt Nano-particles with different concentration of cationic surfactant (CTABr) were [4.12mM/L (2.2~4.16nm), 2.75mM/L (1.5~3.92nm), and 1.37mM/L (1.4~5.66nm)], respectively, Moreover it is easily to find out that the particle size of Pt nano-particles increases with the increase of the dispersant concentration from the image of TEM and SEM. The BET surface area of 20% Pt/C commercial catalyst is 23.518 and the homemade Pt/C catalyst with different Pt concentration were [18% Pt/C (35.904 ) and15% Pt/C (27.995 )], respectively. The cell performance with different concentration of Pt were measured by the fuel cell testing system and the Pt loading is 0.4 mg/cm . The sequence of cell performance of homemade catalyst with different Pt concentration were 18 wt. % > 15 wt. % > 10 wt. %. In addition, these cell performance of homemade catalyst are all superior than that of commercial catalyst (Johnson Matthey). To conclude, the cationic surfactant (CTABr) used as dispersant could efficiently disperse carbon black and platinum, and improve the cell performance simultaneously.總目錄 中文摘要 I 英文摘要 II 圖目錄 VI 表目錄 IX 第一章 緒論 1 1-1 前言 1 1-2 研究動機 4 第二章 文獻回顧 7 2-1 質子交換膜燃料電池（PEMFC） 7 2-1-1 質子交換膜燃料電池(PEMFC)的構造 8 2-1-2 雙極板(Bipolar plate) 9 2-1-3 膜電極組(Membrane electrode assembly) 9 2-1-4極化(Polarization) 15 2-2 載體的應用及發展 16 2-2-1 載體應用 16 2-2-2 擔體效應 16 2-2-3 載體之分散 16 2-3 界面活性劑簡介 18 2-3-1定義與基本性質 18 2-3-2界面活性劑構造及種類 21 2-3-3陽離子性界面活性劑 22 2-3-4微乳化系統與微胞形成 23 2-4奈米粒子的小尺寸效應與表面效應 24 2-4-1小尺寸效應 24 2-4-2表面效應 24 第三章 實驗方法及步驟 25 3-1藥品與材料 25 3-2 儀器設備 26 3-3 實驗步驟 27 3-3-1碳黑載體及分散 27 3-3-2 鉑/碳黑觸媒的製備 27 3-3-3 Nafion的前處理 28 3-3-4膜電極的製備 28 3-4 實驗機制 30 3-4-1 碳黑分散機制 30 3-4-2 Pt 前驅物六水氯鉑酸( ) 還原與分散機制 30 3-5 實驗分析儀器 31 第四章 儀器分析結果與討論 34 4-1 碳黑之特性分析 34 4-1-1碳黑分散測試 34 4-1-2 X光繞射分析 35 4-1-3 掃描式電子顯微鏡分析 36 4-2 不同濃度之CTABR所備製之鉑金結構、粒徑與成份分析 38 4-2-1 X光繞射分析 38 4-2-2掃描式電子顯微鏡與穿透式電子顯微鏡分析 42 4-2-3 EDS能量散布分析與TG/DTA熱重/熱差分析 49 4-3鉑/碳黑觸媒活性面積與電化學分析 54 4-3-1 BET表面積分析 54 4-3-2 循環伏安法觸媒催化性能測試 57 4-4 鉑/碳黑觸媒分析總結 59 4-5 單電池測試 60 4-5-1不同重量百分比之PT/C電極觸媒隨著電池整體溫度變化 60 4-5-2低溫乾燥(DRY AIR)電池效能 63 4-5-3中溫微濕(MIDDLE TEMPERATURE)電池效能 64 4-5-4高溫濕潤(HIGH WET)電池效能 65 4-5-5單電池測試總結 65 第五章 結論 67 參考文獻 68 附錄 71 圖目錄 圖1- 1 燃料電池操作原理示意圖 1 圖1-2 影響白金觸媒催化活性的主要因素 5 圖2- 1 以氫氣為燃料之質子交換膜反應示意圖….……………..….….7 圖2- 2 質子交換膜燃料電池構造示意圖 8 圖2- 3 不同層數膜電極示意圖.. 10 圖2- 4 觸媒顆粒附著在載體上的理想狀態...........................................11 圖2- 5 Nafion質子交換膜化學結構 13 圖2- 6 質子交換膜親水官能基傳遞水氫離子示意圖 14 圖2- 7 為一個典型極化曲線圖 15 圖2- 8 陽離子型(CTABr)界面活性劑分散碳黑示意圖 16 圖2- 9 界面活性劑之水溶液示意圖 19 圖2- 10 水之表面張力示意圖 20 圖2- 11 界面活性劑之構造及分類圖 21 圖2- 12 陽離子型界面活性劑(CTABr)十六烷基三甲基溴化銨 22 圖2- 13 表面張力-濃度曲線與界面活性劑之溶解狀況示意圖 23 圖3- 1 實驗流圖…..……………..………………………………...…....27 圖3- 2 Pt/C.B.觸媒製備流程圖 28 圖3- 3 標準膜電極製備流程圖 29 圖3- 4 Pt/C.B.觸媒漿料圖 29 圖3- 5 碳黑分散流程圖 30 圖3- 6 離子態 還原成金屬態的Pt示意圖 30 圖3- 7 Pt前驅物六水氯鉑酸( )還原與分散流程圖.. 31 圖4- 1 添加碳黑於不同濃度的CTABr溶液中分散之雷射粒徑分析圖 34 圖4- 2 碳黑粉末之X光光譜分圖……………………………………..35 圖4- 3 碳材料原子的結晶排較..………………………………….……36 圖4- 4 碳黑的構造（a）單位平面構造（b）粒子構造（c）鏈狀構造 37 圖4- 5 碳黑 於五萬倍率下的的掃描式電子顯微鏡片…………….... 37 圖4- 6 鉑/碳黑觸媒X光繞射文獻分析圖………………………….…39 圖4- 7 不同濃度(CTABr)所製備之鉑/碳黑(Pt/C)觸媒之X光繞射分析圖……………………………………………………………..... 39 圖4- 8 之背景值X光繞射分析圖 40 圖4- 9 之(CTABr)X光繞射分析圖 40 圖4- 10不同濃度分散劑(CTABr)所製備Pt之(111)晶面X光繞射分析圖 41 圖4- 11不同濃度分散劑(CTABr)所製備Pt之(220)晶面X光繞射分圖.41 圖4- 12 商用(Johnson Matthey)之的(20% wt)鉑/碳黑觸媒於三十萬放大倍率下的掃描式電子顯微鏡照片 43 圖4- 13 濃度4.12 mM/L合成之的鉑/碳黑觸媒於三十萬放大倍率下的掃描式電子顯微鏡照片圖 44 圖4- 14 濃度2.75 mM/L合成之的鉑/碳黑觸媒於三十萬放大倍率下的掃描式電子顯微鏡片圖……………………………………..... 44 圖4- 15 濃度1.37 mM/L合成之的鉑/碳黑觸媒於三十萬放大倍率下的掃描式電子顯微鏡照圖……………………………………......45 圖4- 16 商用(Johnson Matthey)之觸媒於十萬放大倍率下的穿透式電子顯微鏡照片………………………………………………..…....46 圖4- 17 濃度4.12 mM/L合成之觸媒於十萬放大倍率下的穿透式電子顯微鏡照片………………………………………………..…....46 圖4- 18 濃度2.75 mM/L合成之觸媒於十萬放大倍率下的穿透式電子顯微鏡照片……………………………………………………..47 圖4- 19 濃度1.37 mM/L合成之觸媒於十萬放大倍率下的穿透式電子顯微鏡照片…………………………………………………….. ...47 圖4- 20 濃度4.12 mM/L (CTABr)所製備之Pt/C觸媒(SAD)繞射圖 48 圖4- 21 濃度2.75 mM/L(CTABr)所製備之Pt/C觸媒(SAD)繞射圖…..48 圖4- 22 濃度1.37 mM/L(CTABr)所製備之Pt/C觸媒 (SAD)繞射圖…49 圖4- 23 商用(Johnson Matthey) 20%的Pt/C觸媒EDS成份分析 50 圖4- 24 濃度4.12 mM/L (CTABr)所製備之Pt/C觸媒EDS成份分析 51 圖4- 25 濃度2.75 mM/L (CTABr)所製備之Pt/C觸媒EDS成份分析 52 圖4- 26 濃度1.37 mM/L (CTABr)所製備之Pt/C觸媒EDS成份分析 53 圖4- 27 不同濃度(CTABr)所備製之Pt/C觸媒之熱重分析圖…………54 圖4- 28 Johnson Matthey 20% Pt/C電極觸媒氮氣等溫吸脫附曲線 55 圖4- 29 4.12mM/L CTABr 18% Pt/C電極觸媒氮氣等溫吸脫附曲線 55 圖4- 30 2.75mM/L CTABr 15% Pt/C電極觸媒氮氣等溫吸脫附曲線 56 圖4- 31 1.37mM/L CTABr 15% Pt/C觸媒氮氣等溫吸脫附曲線 56 圖4- 32 鉑/碳黑觸媒的循環伏安法曲線圖曲線 58 圖4- 33 Johnson Matthey 20% Pt/C電極觸媒 Pt loading 電壓-電流密度-功率密度曲線圖之電壓-電流密度曲線 61 圖4- 34 4.12mM/L CTABr 18% Pt/C電極觸媒 Pt loading 電壓-電流密度-功率密度曲線圖 61 圖4- 35 2.75mM/L CTABr 15% Pt/C電極觸媒 Pt loading 電壓-電流密度-功率密度曲線圖 62 圖4- 36 1.37mM/L CTABr 10% Pt/C電極觸媒 Pt loading 電壓-電流密度-功率密度曲線圖 62 圖4- 37 低溫乾燥(Dry Air) Pt loading 電壓-電流密度-功率密度曲線圖 63 圖4- 38 中溫微濕(Middle Temperature) Pt loading 電壓-電流密度-功率密度曲線圖 64 圖4- 39 高溫濕潤(High Wet) Pt loading 電壓-電流密度-功率密度曲線圖 65 表目錄 表1- 1 白金在PEMFC中的陰陽極催化過程 3 表1- 2 白金在PEMFC中的陰陽極催化過程 5 表1- 3 白金在PEMFC中的陰陽極催化過程 6 表2- 1 目前市面上販售的質子交換膜種類………..………..……….…13 表2- 2 白金在PEMFC中的陰陽極催化過程 24 表2- 3 白金在PEMFC中的陰陽極催化過程 24 表3- 1 藥品與材料….………………………………..……………….….25 表3- 2 儀器設備 26 表4- 1 Pt(111) 與Pt(220)之XRD所計算之粒徑與化學活性面積……42 表4- 2 EDS與TGA之 Pt/C成份析…………….…………………….54 表4- 3 Pt/C 電極觸媒比表面積 ( ) 57 表4- 4 不同濃度的CTABr所製備之觸媒的開路電壓、最大電流密度及 最大功率 66 表4- 5 商用觸媒(Johnson Matthey)Pt/C 20wt%與自製不同wt% Pt/C觸媒的開路電壓、最大電流密度及最大功率 6

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