|Abstract: ||本研究之目的在於利用酒精燈火焰來合成奈米碳結構。研究中，分別使用99.8%丁醇(n-Butanol)、95%乙醇(Ethanol)兩種液態燃料，並摻混不同體積百分比(10%、20%、30%)之氨水(純度為25%)，形成丁醇/氨水和乙醇/氨水混合燃料，探討不同液體燃料(純丁醇、丁醇/氨水、純乙醇、乙醇/氨水)之火焰型態、溫度場以及取樣位置對火焰燃燒合成奈米結構的影響。研究中依序進行火焰型態觀察、溫度量測，接著將鎳網格置於酒精燈芯中心上方不同的軸向位置，進行沉積取樣，取樣時間為2分鐘。然後，再以掃描式電子顯微鏡(FE-SEM)和高解析場發射掃描穿透式電子顯微鏡(HR-TEM)觀察分析不同實驗條件下所生成奈米碳結構的微結構和形態。最後，進行奈米結構的拉曼分析。結果發現，丁醇/氨水火焰會隨著氨水濃度的增加(0%、10%、20%、30%)，根部藍焰部分會明顯的增加；而乙醇火焰則隨著氨水濃度的增加，火焰焰色明顯的由橘黃色逐漸轉變為深褐色。SEM分析結果顯示，當丁醇濃度為100%時，在高度z = 6、8、10、12 mm均可生成奈米碳管，其生成溫度範圍約為700~950℃。當丁醇濃度為90%時，在高度z = 10、12、14、16、18、20、22 mm均可合成奈米碳球，其生成溫度範圍約750~950℃。當丁醇濃度為80%時，在高度z =4 mm可合成奈米碳管，其生成溫度範圍約為700~740℃；而在高度z =12、14、16、18、20、22 mm均可合成奈米碳球，生成溫度範圍約為825~1030℃。當丁醇濃度為70%時，在高度z =4、6 mm(溫度範圍約為620~750℃)可生成奈米碳管；而在高度z =12、14、16、18、20 mm(溫度範圍約為800~1040℃)，均可生成奈米碳球。當乙醇濃度為100%時，在高度z =4、6 mm(溫度範圍約為520~620℃)均可生成奈米碳管。當乙醇濃度為90%時，在高度z = 4、6、8 mm(溫度範圍約為750~850℃)均可生成奈米碳管。當乙醇濃度為80%時，在高度z = 4、6、8 mm(溫度範圍約為690~780℃)均可生成奈米碳管。乙醇濃度為70%，在高度z = 4、6 mm(溫度範圍約為655~770℃)可生成少量奈米碳管，而在高度z =8、10、12、14、16 mm(溫度範圍約為840~1030℃)均可合成較大量奈米碳管；亦即，在高度z = 8 mm時可發現大量CNTs生成，接著在高度z =10 mm達到最大量，之後則隨著高度增加，其生成量逐漸變少。此外，由HR-TEM分析顯示，當丁醇濃度為100%且高度為z = 10、12 mm以及丁醇濃度為90%且高度z = 14、18 mm時，可發現在SEM無法觀察到的石墨烯。|
This study aimed at investigating the synthesis of carbon nanostructures in butanol/aqueous ammonia and ethanol/aqueous ammonia flames using an alcohol lamp burner. Pure n-butanol (purity 99.8%), pure ethanol (purity 95%), n-butanol/aqueous ammonia (25% NH3) blends, and ethanol/aqueous ammonia blends were used in this study. Aqueous ammonia was mixed with various proportions (10, 20, and 30%) in butanol or ethanol for use as liquid fuels. A nascent nickel mesh was employed as the catalytic metal substrate to collect deposit materials. The deposition time was two minutes. Additionally, scanning electron microscope (FE-SEM) and high resolution field emission scanning transmission electron microscopy (HR-TEM) were used to observe and analyze the microstructure and morphology of generated carbon nonostructures under different experimental conditions.First, flame appearances were observed. With increasing the content of aqueous ammonia, it was found that the blue part generated at the yellow flame base became more apparent for the n-butanol/aqueous ammonia flames, and that the flame color changed gradually from yellow to brown for the ethanol/aqueous ammonia blends. From the results of SEM analysis, it was observed that, for pure n-butanol, carbon nanotubes (CNTs) were synthesized at the axial positions z = 6, 8, 10 and 12 mm above the wick where the temperature was in the range of about 700 – 950℃. As n-butanol concentration was 90% in the n-butanol/aqueous ammonia blends, carbon nano-onions (CNOs) were produced at the heights z = 10, 12, 14, 16, 18, 20 and 22 mm where the temperature was between 750 and 950℃. For the n-butanol concentration of 80%, CNTs were fabricateded at a lower axial position z = 4 mm, where the temperature was identified to lie between 700 and 740℃; however, at higher heights z = 12, 14, 16, 18, 20 and 22 mm, CNOs were synthesized, where the temperature was located in the range of 825 – 1030℃. As the n-butanol concentration was 70%, CNTs were found at lower hights z = 4 and 6 mm where the temperature range was within 620 – 750℃; however, at higher heights z = 12, 14, 16, 18 and 20 mm with a temperature range of about 800 – 1040℃, CNOs were observed.For pure ethanol (100% ethanol), at the height z = 4 and 6 mm (where the temperature range was about 520 – 620℃), CNTs were generated. For the ethanol concentration of 90%, at the heights z = 4, 6 and 8 mm (where the temperature was ranged approximately from 750 to 850℃), CNTs were synthesized. Under the operating conditions of ethanol concentration being 80%, at the heights z = 4, 6 and 8 mm (where a temperature range of about 690 – 780℃ was generated), CNTs were produced. As ethanol concentration was 70%, at the heights z = 4 and 6 mm (where the temperature range was about 655 – 770℃, few CNTs were fabricated; whereas, at the heights z = 8, 10, 12, 14 and 16 mm (where the temperature range of about 840 – 1030℃ was produced), more CNTs were synthesized. With increasing axial position from z = 8 mm progressively, a larger amount of CNTs were synthesized at z = 8 mm, achieved the maximum yield at z = 10 mm afterwards, and then the formation of CNTs decreased gradually.Based on the results of HR-TEM analysis, it is noteworthy that few layer graphenes were also observed (which were not found easily in SEM analysis) when the concentration of n-butanol was 100% and the sampling positions were located at z = 10 and 12 mm or when the concentration of n-butanol was 90% and the sampling positions were placed at z = 14 and 18 mm. Moreover, graphenes were not observed in pure ethanol and ethanol/aqueous ammonia flames.