- 學位論文
以原子層沉積法合成奈米鉑觸媒於奈米碳管及石墨烯複合材以應用於質子交換膜燃料電池
Atomic Layer Deposition of Pt Nanocatalysts in Carbon Nanotube and Graphene Hybrids for PEM Fuel Cells
摘要
本研究提供一種以原子層沉積法沉積低覆載量白金觸媒製備高性能氣體擴散電極，以應用於高效能質子交換膜燃料電池。由奈米碳管及氧化石墨烯複合材料作為之氣體擴散電極基材，具有高表面積、高導電性以及優異的氣體穿透特性。本實驗使用原子層沉積技術合成奈米白金觸媒於奈米碳管及氧化石墨烯複合基材之上，藉由調控原子層沉積循環次數控制白金觸媒之披覆量及粒徑於不同幾何結構之碳材表面。 實驗結果顯示，隨著原子層沉積循環次數增加，白金觸媒之沉積量及粒徑大小呈線性成長，證實了原子層沉積之自我限制機制特性。原子層沉積50-400圈時，觸媒粒徑大小之分佈為2-15 nm，且展現均勻且良好的分散性及披覆量。膜電極組測試結果顯示，本研究所製備的電極比起商購電極展現較高發電功率，於奈米碳管及氧化石墨烯系統分別於50圈及100圈時最高可達到7.7 kW g-1及2.4 kW g-1，證實以原子層沉積技術可製備低觸媒附載量及高能量密度之低溫質子交換膜燃料電池之觸媒電極，並提高其商業化之可行性。
並列摘要
This study adopts an atomic layer deposition (ALD) to prepare ultra-low Pt loading over the surface of carbon nanotubes (CNTs) and graphite oxide (GO) hybrids, showing superior power density in single-stack proton exchange membrane fuel cells (PEMFCs). These novel gas diffusion electrode (GDE) composites generate stereo carbon framework, inducing vast surface area, electron conduction, and gas transport. Nanoparticulate Pt has been well dispersed onto one and three-dimensional carbon framework, consisted of CNTs and GO hybrids, through an ALD route. The ALD cycle number (i.e., 50, 100, 200, and 400 cycles) serves as a key factor in accurately controlling the particle size and the weight loading distribution of Pt deposits. Two linearity plots of the Pt loading and the particle size versus the ALD cycle number confirm the presence of self-limiting reaction steps. The particle size of Pt nanoparticles shows an increase with the ALD cycle, i.e., 2−15 nm within 50−400 ALD cycles. The GDE equipped with as-grown Pt catalysts on CNTs and GO hybrids, generates superior peak power density of 7.7 kW g-1 and 2.4 kW g-1 at 75°C, respectively, showing an advance design of GDE for PEMFCs. On the basis of the results, the ALD approach is capable of synthesizing well-dispersed Pt nanoparticles onto carbon composites, forming the advanced design of catalyst electrode for PEMFCs.