- 期刊
奈米國家型計畫「ALD於氣體擴散層製備晶粒＜2nm觸媒應用於高效能燃料電池」計畫執行簡介
Introduction to National Research Program for Nanoscience and Technology-"Metallic Catalysts (Grain Size<2 nm) Fabricated by Atomic Layer Deposition on Gas Diffusion Layers for High Efficiency Fuel Cells"
摘要
本計畫之研究動機是以碳材結構與觸媒設計為研究基礎，結合氣體擴散層(Gas Diffusion Electrode, GDE)創新設計與新穎原子層沉積技術(Atomic Layer Deposition, ALD)製備顆粒＜2 nm之高性能觸媒，降低觸媒使用量（至少一個級數），大幅提升燃料電池性能，並降低電池成本。本研究團隊將整合本校目前具有之優良燃料電池設計與驗證能力，開發新穎奈米碳結構氣體擴散電極，以排列有序之石墨球與奈米碳管陣列取代傳統散亂排列之微孔層。此結構具有兩項優勢：(1)氣體擴散阻力低且(2)因碳管與石墨導電性佳，電子傳導迅速，將有利於電極性能提升。再者，為提升電化學觸媒活性，本計畫利用ALD技術製備高性能觸媒於奈米碳結構上，ALD 可利用前驅物氣體與基板表面所產生的自我侷限(Self-limiting)交互反應，而達到極佳顆粒均勻性與尺寸控制能力（可達Å等級），其深徑比(Aspect Ratio)最高可達到2000:1，適合應用於上述兩種碳結構上沉積金屬觸媒，形成分布均勻的奈米顆粒，例如Ir、Pd、Ru與Pt等貴金屬或其合金奈米顆粒，並具有良好的分散性與顆粒尺寸分佈（≤2 nm，文獻值約為3 nm）。此外，本團隊之先前研究已證實ALD觸媒具極低之Pt負載量(~0.016 mg/平方公分)，遠低於商業用膜電極(20 mg/平方公分)以及文獻報導之最低值(≈0.2 mg/平方公分)，且擁有更優異之電化學活性。
關鍵字
無資料並列摘要
Proton exchange membrane fuel cells (PEMFCs) require anode and cathode catalyst layers that have excellent electrochemical activity. Membrane electrode assembly (MEA) is one of the key components in achieving high efficiency of PEMFCs. In MEA, design of gas diffusion electrode (GDE) thus plays an important role in affecting the performance of MEA. Commonly-used design factors, such as microporous layer stacking, hydrophobic/hydrophilic control, and electrochemical activity, has been reported. However, there are a few literatures using a systematic and theoretical research on the investigation of GDEs. The motive of this proposal is based on carbon-based texture and catalyst characterization to develop a novel GDE design. An atomic layer deposition technique enables the preparation of Pt catalyst with grain size ＜ 2 nm, forming high efficiency catalysts. Due to its high electrochemical activity, the Pt loading in GDEs is at least one order of magnitude less than commercial Pt usage, thus increasing the performance of fuel cells.