直接甲醇燃料電池係利用氧化還原反應產生電能，分別在陽極端與陰極端直接供給甲醇與氧氣。近年來，直接甲醇燃料電池的焦點在於更高的效率與更低的成本，在本論文中引進奈米尺寸的概念，同時將觸媒與碳載體尺寸縮小至奈米級，在碳載體的部份本研究利用MW-PECVD系統直接成長於碳布上的奈米碳管，有別於傳統塗布製程，本研究以奈米碳管作為載體，降低了碳管與碳布之界面阻抗，故擁有高表面積與高電子傳遞的特性，適合作為承載電觸媒的載體。在觸媒的部份，本實驗利用化學法製備鉑觸媒奈米顆粒，微波電漿化學氣相沈積法具有成本低、實驗設備簡便及觸媒分佈均勻等優點，在本研究中奈米碳管上鉑觸媒負載量約0.1mg/cm^2，由TEM觀察平均粒徑約2nm，其相對應之觸媒表面活性面積為800 cm^2/mg，在zeta電位測試結果，顯示在pH11的膠體溶液中，具有最大電斥力，zeta電位約為60mV，對照TEM結果可知當zeta電位越大可得到越小粒徑之鉑觸媒奈米顆粒。直接甲醇燃料電池係利用氧化還原反應產生電能，分別在陽極端與陰極端直接供給甲醇與氧氣。近年來，直接甲醇燃料電池的焦點在於更高的效率與更低的成本，在本論文中引進奈米尺寸的概念，同時將觸媒與碳載體尺寸縮小至奈米級，在碳載體的部份本研究利用MW-PECVD系統直接成長於碳布上的奈米碳管，有別於傳統塗布製程，本研究以奈米碳管作為載體，降低了碳管與碳布之界面阻抗，故擁有高表面積與高電子傳遞的特性，適合作為承載電觸媒的載體。在觸媒的部份，本實驗利用化學法製備鉑觸媒奈米顆粒，微波電漿化學氣相沈積法具有成本低、實驗設備簡便及觸媒分佈均勻等優點，在本研究中奈米碳管上鉑觸媒負載量約0.1mg/cm^2，由TEM觀察平均粒徑約2nm，其相對應之觸媒表面活性面積為800 cm^2/mg，在zeta電位測試結果，顯示在pH11的膠體溶液中，具有最大電斥力，zeta電位約為60mV，對照TEM結果可知當zeta電位越大可得到越小粒徑之鉑觸媒奈米顆粒。
Carbon nanotubes (CNTs) were directly grown on a carbon cloth (DGCNTs) as catalyst supports applied in a direct methanol fuel cell (DMFC). The iron nanoparticles were deposited on a carbon cloth as the assisted catalysts for the CNT growth. The DGCNTs were synthesized by the microwave plasma-enhanced chemical vapor deposition in the gaseous precursors of H(subscript 2)/CH(subscript 4)/N(subscript 2). The diameter of DGCNT was ca. 10-20 nm and the structure was bamboo-like. Subsequently, Pt and Ru nanoparticles were deposited on DGCNTs (Pt-Ru/DGCNT) by the sputtering method. The formation of Pt-Ru nanoparticles were the high-degree alloy and the particle size were ca. 3.54 nm. For the membrane-electrode-assembly (MEA) fabrication, the 0.2 mg-cm^-2 metal-loading of Pt-Ru/DGCNT and the 4.0 mg-cm^-2 of Pt blacks were employed as the anode and cathode, respectively, which the Nafion 117 as the membrane was sandwiched in between two electrodes. The polarization curve of MEA was examined by feeding 1 M methanol and purity oxygen to anode and cathode, respectively, which the maximum power density was 1.52 W-Pt-mg^-1 at 60oC. The low amount of precious metal loaded on DGCNTs applied in a MEA shows a high performance, which is suitable for a DMFC.
