本研究探討不同氧化條件對於鉍金屬奈米線應用於光觸媒反應之表現。研究中的鉍奈米線是以陽極氧化鋁(Anodic Aluminum Oxide, AAO)作為模板，利用其輔助真空壓鑄法製備而成，接著進行氧化處理以獲得氧化鉍奈米線。以孔徑90 nm之陽極氧化鋁作為模板，製備出奈米線之線徑會和模板之孔徑符合。氧化處理時將溫度設定在300 ℃並持溫，氧化處理時間分別為1 h至7 h。由於在使用酸液去除模板時會產生氧化層包覆奈米線外層，因此在氧化處理的過程中，當氧化溫度高於材料熔點時，奈米線外部會由於氧化層保護而不會熔化變形，保持原本實心形狀。進行過熔點之氧化處理時，奈米線內部為熔融態，將加速擴散反應，以獲得氧化鉍奈米線。本研究所獲得之β-Bi2O3奈米線將進行特性分析，藉由XRD及TEM鑑定晶體結構，證實了鉍在氧化溫度300 ℃並持溫7 h之氧化處理條件下，能夠與氧充分反應形成氧化鉍。從SEM之微觀觀察中，可以觀察到不同氧化時間之氧化鉍奈米線都是筆直且線徑均一的，因此證實利用模板輔助真空壓鑄法是能夠成功製備出線徑和模板孔徑符合之奈米線。通過EDS作成分分析，結果顯示鉍及氧之原子比為2:3，證實鉍奈米線皆已被氧化形成氧化鉍。進一步使用UV-vis及PL進行光學特性之分析，其結果顯示，隨著氧化時間增加，氧化鉍之結構越穩定，導致電子電洞再結合速率提高，也因此PL光譜上之強度會增強。另一方面，將上述所製備之β-Bi2O3奈米線利用照光降解實驗來探討其光觸媒性質，並與商用之α相及β相氧化鉍粉末作分析比較。在4 h之照光降解實驗後，β-Bi2O3奈米線之分解效率下降了80.3%，相較於商用α相及β相氧化鉍粉末，分別多了29.8%及7.7%，由此可知本研究之β-Bi2O3奈米線光觸媒性質優於商用α相及β相氧化鉍粉末。

In this study, the purpose is to investigate the effect of different oxidizing treatments on the photocatalytic activity of Bi nanowires. The β-Bi2O3 nanowires were fabricated by vacuum injection molding process within anodic aluminum oxide (AAO) template and following oxidation process. AAO template with a pore size of 90 nm was fabricated by anodization. The diameter of nanowires is identical with the pore size of AAO. Due to the outer layer of nanowires covered by oxide layer after removing the template with acid solution, the nanowires were not melted and deformed while the oxidation temperature was higher than Bi melting point of Bi during the oxidation process. During the oxidation process, the core of nanowire was at a molten state, inducing an acceleration of diffusion reaction to form β-Bi2O3 nanowire. XRD and TEM analyses displayed that the bismuth could fully react with oxygen to form the β-Bi2O3 while the oxidation duration reached 7 h at 300 ℃. The microstructure was observed by SEM, which shows that the β-Bi2O3 nanowires with different oxidizing duration were straight and uniform in diameter. It could be confirmed that the nanowires with uniform diameter were be successfully fabricated by using vacuum injection molding process with anodic aluminum oxide template. The EDS analysis demonstrated that the atomic ratio of bismuth and oxygen is 2:3, it could be further confirmed that the Bi nanowires have been oxidized to form β-Bi2O3 nanowires. The results of UV-vis and PL demonstrated that structure became stable with increasing oxidation duration which caused the recombination rate of electron and hole raising resulting in the stronger intensity in PL spectrum. In addition, the commercial bismuth oxide powders with α and β phase were compared with β-Bi2O3 nanowires in this research. After 4 h of photodegradation experiments, the decomposition efficiency of β-Bi2O3 nanowires decreased to 80.3%, which was high more than commercial bismuth oxide powders of 29.8% and 7.7%, respectively. The results displayed that the photocatalytic activity of β-Bi2O3 nanowires were better than commercial bismuth oxide powder with α and β phase.

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