質子交換膜燃料池是備受矚目的發電裝置。當燃料為氫氣即稱為氫能燃料電池，可將氫氣和氧氣的化學能轉換成電能，不僅發電效率高且低汙染，因此已是重要的替代能源。為了降低燃料電池系統實際操作時的成本及電壓損失，研發高活性的觸媒乃當務課題。目前，碳黑擔載鉑觸媒 (carbon black supported platinum, Pt/C) 是最常見的燃料電池觸媒，不過，近幾年石墨烯廣受熱議，其獨特的結構與特性，使其可望取代碳黑成為更優良的觸媒擔體材料。
本論文旨在探討石墨烯的表面性質對氫能燃料電池觸媒的影響，並藉由高溫處理，改變金屬觸媒與擔體的特性，以提升其催化活性。另外，亦比較單金屬觸媒 (鉑) 與雙金屬觸媒 (鉑和鈷) 的表現。本研究中使用三種市售石墨烯作為擔體材料：石墨烯奈米薄片(graphene nanosheet, GNS)、氧化石墨烯一號和二號 (graphene oxide: GO1, GO2)。三者的主要差異為其表面的碳與氧比率 (C : O ratio)。於本論文中所有的石墨烯擔載金屬觸媒皆是以乙二醇還原法進行合成。氧化石墨烯部份形成還原態 (reduced graphene oxide, rGO)，製得之觸媒係以Pt/GNS、Pt/rGO1和Pt/rGO2命名，其中，對Pt/rGO2 之熱處理，是改變加熱溫度和時間而觀察觸媒的物性及催化活性之變化。以同樣方法製備的鉑鈷雙金屬觸媒 (PtCo/rGO2)，也與前述的單金屬觸媒 (Pt/rGO2) 相互比較。
擔體與觸媒的型態是以穿透式電子顯微鏡 (TEM) 進行觀察；晶體結構與晶粒尺寸可由X射線繞射分析儀 (XRD) 得知。此外，擔體、雙金屬觸媒以及 Pt/rGO2 觸媒經熱處理後各者不同表面元素組成比例的變化是以掃描電子顯微鏡及能量分散光譜儀 (SEM/ EDS) 與X射線光電子能譜儀 (XPS) 進行分析。石墨烯的缺陷與分子結構則使用拉曼光譜儀 (Raman spectroscope) 和傅立葉轉換紅外光譜 (FTIR) 進行鑑定。
對觸媒之電化學活性面積及催化氧氣還原反應能力之比較是以循環伏安法和線性掃描法進行計算與比較。文中探討的自製觸媒有單金屬觸媒：Pt/GNS、Pt/rGO1、Pt/rGO2，以及對應的鉑鈷雙金屬觸媒。此外，亦探究觸媒經熱處理後的電化學活性表現。繼之，將自製的觸媒應用於氫燃料電池之效能測試，乃是更換陰極觸媒的種類，但固定陽極觸媒為Pt/rGO2，其中以Pt/GNS為陰極觸媒時，電池性能表現最優：開環電壓為 0.982 V，最高能量密度是125 mW cm-2。Pt/rGO1和Pt/rGO2 的電池性能表現相近，但都不及Pt/GNS；且Pt/rGO2經高溫處理後，最高電能密度可獲提升。此外，以雙金屬觸媒作為陰極觸媒時的電池性能則不如單金屬觸媒。
綜合上述，於本研究中製得的金屬觸媒確實可於氫能燃料電池系統使用並展現放電效率，顯示具有實際應用的潛力。不過，未來仍須更進階的研究，以強化燃料電池整體的性能表現。

The proton exchange membrane fuel cell (PEMFC) is considered to be one of the most promising energy sources because of its high energy conversion efficiency and low pollutant emission. However, high cost, sluggish oxygen reduction reaction and low durability are major defects that hamper PEMFCs commercialization. The key solution to the problems lies in catalyst materials. Pt nanoparticles supported on carbon black (Pt/C) are the most common catalysts, yet their properties are not fairly satisfactory. Thus, an emerging material – graphene – draws extensive attention on account of its unique structure and characteristics.
In this thesis, three different graphenes with varied surface oxygen functional groups concentration are used as the fuel cell catalyst supporting materials. Pt nanoparticles deposited on the supports are prepared by ethyl glycol reduction method. Reduced graphene oxides are also formed from the reduction process. The oxygen content of the graphene supports and the pre-heating treatment on the supports essentially affect the performance of the fuel cell system. Evaluation on the fuel cells are scrutinized with spectroscopic, microscopic and electrochemical analyses. The results show that the Pt nanoparticles supported on the graphene, which contains the least oxygen functionalities, exhibit the highest electrochemical surface area, highest oxygen reduction reaction activity and superior single-cell performance. Consequently, a maximum power density of 125 mW cm-2 and an open-circuit potential of 0.982 V are achieved. Also, it is observed that the pre-heating treatment causes significant structural and morphological modification of the catalysts leading to an enhancement in catalytic activity. In addition, Pt-Co bimetallic catalysts are also synthesized and compared to the monometallic ones.
In summary, the prepared catalysts are utilizable in PEMFCs and shows moderate efficiency, which implies they possess the potential of practical implementation. Nevertheless, further investigation is required in order to improve the overall cell performance.

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