The influences of Al(OH)3 powder on the hydrogen generation rate from Al/water chemical reaction
| Autor: | Yu-Chieh Wen, 溫于傑 |
|---|---|
| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 It is difficult to generate hydrogen from reaction of aluminum powders and water at room temperature under 1 atm. From previous studies, it’s known that aluminum hydroxide is a good catalyst for hydrogen generation from Al/water system, especially those synthesized from 1:3.5 mole ratio (Al(NO)3:NaOH) ice bathed for 48 h. The reaction Al:Al(OH)3:H2O = 3:10:30 system at pH=12 can complete 100% yield of hydrogen generation in 90 s,Aluminum hydroxide powder was observed by field-emission scanning electron microscope (FE-SEM) and Powder X-ray diffraction (XRD). It shows that Al (OH)3 has a flaky shape, small hexagonal plate particles (~ 100-300 nm ) in a Bayerite crystal structure. Although, the aluminum hydroxide powders synthesized in our laboratory have excellent effect on the hydrogen generation in Al/water system, it still has drawbacks of low yield and lengthy synthesizing time. Therefore, in this study, I focus on how to cut down the duration of synthesizing time by using alternative synthesizing conditions, where a CTAB was added to promote the formation of bayerite phase. In order to reduce the required amount of catalyst while keep the generation rate, I used the milling process for Al and Al(OH)3. Layer and hexagonal β-phase Al(OH)3 structure is the important key to get good effect of hydrogen generation, compared with commercial Al(OH)3 which are α-phase. In order to form Bayerite Al(OH)3 more efficiently, we modified the commercial α-phase powder into hexagonal-layer β-phase, by dissolving and re-precipitation process. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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