本論文使用直接成長奈米碳管於碳布上做為觸媒載體,用於直接甲醇燃料電池電極。吾人使用鐵鍍在碳布表面做為成長奈米碳管的催化劑,並且使用微波輔助化學氣相沉積法在碳布上直接成長奈米碳管。直接成長奈米碳管直徑約10到20nm。由穿透式顯微鏡證明奈米碳管是竹節狀結構。接著,吾人使用物理氣相沉積法將鉑和釕濺鍍在直接成長奈米碳管上,作為直接甲醇燃料電池的陽極。使用X光繞射法,證明鉑和釕形成高度的合金,而且顆粒大小約3.54nm。採用0.20mg cm^(-2)鉑和釕的金屬量在直接成長奈米碳管上作為陽極,4.0mg cm^(-2)鉑在碳布上作為陰極,與Nafion117作為膜,製作膜電極組(MEA, membrane-electrode assembly)。極化測試在1M的甲醇和純氧的環境底下進行。所得到的極化曲線顯示,電池在60℃時,最大功率接近1.52WPt-mg^(-1),證明此方法使用少量的觸媒金屬在直接成長奈米碳管上,可以得到相當好的效率。
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 H2/CH4/N2. 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. 3.54nm. For the membrane-electrode-assembly (MEA) fabrication, the 0.2 mg-cm^(-2) metal-loading of Pt-Ru/DGCNT and the 4.0mg-cm^(-2) of Pt blacks were employed as the anode and cathode, respectively, which the Nafion117 as the membrane was sandwiched in between two electrodes. The polarization curve of MEA was examined by feeding 1M methanol and purity oxygen to anode and cathode, respectively, which the maximum power density was 1.52 W-Pt-mg^(-1) at 60℃. The low amount of precious metal loaded on DGCNTs applied in a MEA shows a high performance, which is suitable for a DMFC.