- 學位論文
鋁水快速產氫及添加劑氫氧化鋁之影響
Study on the rapid generation of hydrogen from aluminium and water system and the effect of aluminium hydroxide as catalytic additive.
摘要
利用硝酸鋁:氫氧化鈉莫耳比 = 1:3.5，冰浴下合成的氫氧化鋁有十分良好的催化效果，並且在Al : Al(OH)3 : H2O = 3g : 10g : 30mL系統中，水溶液pH=12時，90秒內就可以完全產氫完畢。場發射掃描式電子顯微鏡 ( FE-SEM ) 顯示此氫氧化鋁擁有片狀結構，且顆粒較細微(~100-300nm)，因此有極佳的催化效果。 由於不同的氫氧化鋁對鋁水產氫效果不同，本研究藉由不同結構，和市售的氫氧化鋁做比較可以得知，自製氫氧化鋁在最佳條件下為顆粒細小，且為β相的氫氧化鋁，比起市售非結晶相、α相、AlOOH等氫氧化鋁催化效果都來的優良。推測為β相的結晶結構具有較多活躍位置(active site)的六角形結晶是產氫較佳的原因。且可從鋁水反應後之氫氧化鋁得知顆粒越小的β相氫氧化鋁其催化效果越好。 利用水熱法(氨水)所改質的氫氧化鋁可以改善原本反應性不佳的氫氧化鋁。因此可以減少自製氫氧化鋁的時間。從粉末X-Ray繞射儀 ( XRD ) 中可以得知利用水熱法改質的氫氧化鋁都是AlOOH；從SEM可以看出約為5~60μm的顆粒大小左右的顆粒。但也可得知利用水熱法(氨水)所改質的氫氧化鋁為片狀結構團聚而成的，其片狀物質具有大量的active site，故催化效果十分良好。因此得知active site數量與催化效果成正比。
並列摘要
Aluminum hydroxide has a very good catalytic effect that using mole ratio of aluminum nitrate: sodium hydroxide = 1: 3.5 and under ice synthesis.When Al : Al(OH)3 : H2O = 3g : 10g : 30mL systems and solution pH=12,hydrogen haas complete to production within 90s.FE-SEM show this aluminum hydroxide has flaky structure and finer particles (~ 100-300nm), and therefore has an excellent catalytic effect. Because different aluminum hydroxide has different effect in Al/Water hydrogen production system, the present study by compare of different commercial aluminum hydroxide. We know homemade aluminum hydroxide has optimum conditions,that powder is fine particles and crystalline phase is β phase.Compare to commercial aluminum hydroxide ,that crystalline phase has α phase、AlOOH、and amorphous phase, homemade aluminum hydroxide have excellent catalytic effect. Good hydrogen production is presumed to be homemade aluminum hydroxide with more active sites that is β phase and hexagonal structure. The study is know aluminum hydroxide has better catalytic effect at Al/water hydrogen production which powder has smallerβ phase particles. By hydrothermal method (ammonia) modified aluminum hydroxide can improve the reaction of the poor original aluminum hydroxide. XRD can be learned from the hydrothermal method modified aluminum hydroxide crystalline is a AlOOH. SEM can be seen from about 5 ~ 60μm particle size of particles. By using ammonia hydrothermal method modified aluminum hydroxide is sheet shape and clusters, which flaky material having a large number of active site,so the catalytic effect is very good. Therefore, the catalytic effect that is proportional to the number of active site.