鋁金屬有機骨架由非序化中間物轉換至結晶態之研究
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2023
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本論文研究鋁金屬有機骨架由非序化至有序化的結構轉換過程，在第一部分中，挑選三種不同結構的鋁金屬有機骨架，分別是MIL-53、MIL-100、CAU-10，在不同反應時間下合成非序化的中間產物後，透過雙溶劑置換及加熱抽真空將溶劑脫附並促使結構重排進而探討結晶化的過程，鑑定方式則用粉末X光繞射儀(PXRD)、場發射式掃描電子顯微鏡(FE-SEM)、比表面積及孔隙分析儀及熱重分析儀(TGA)等觀察MOF的結構、形貌及吸附性能等等，結果說明可以透過雙溶劑置換及加熱抽真空促使MOF骨架有序化，在PXRD中可以看到結晶訊號由非序化到有序化，且在較短時間合成的產物也具有與文獻時間合成的產物相似的性能。第二部分則針對熱/室溫DMF純化動作探討對MOF結構的影響，結果顯示在PXRD沒有表現出明顯的差異性，而經過熱DMF攪拌清洗的產物在比表面積及氮氣吸附量會有所下降，而在場發射式掃描電子顯微鏡可以觀察到MOF在經過熱攪拌清洗會具有尺寸較小的晶體出現，從上述結果顯示出熱DMF會對MOF造成破壞性。
This paper investigates the structural transformation process of aluminum metal-organic frameworks (MOFs) from amorphous to crystal. In the first part of this thesis, three different aluminum-based metal-organic frameworks (MOFs) were selected:MIL-53, MIL-100, and CAU-10. amorphous intermediates were synthesized at different reaction times, and the crystallization process was explored by using two solvent exchange (TOSE) and heat under vacuum (HEVA) to induce solvent removal and structural rearrangement. Powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FE-SEM), surface area and porosity analyzer, and thermal gravimetric analysis (TGA) were used to analyze the MOF structure, morphology, and adsorption performance. The results showed that MOF frameworks could be ordered through TOSE and HEVA. PXRD reveals the crystalline signals of a transition from amorphousto crystal, Moreover, products synthesized in shorten time exhibited similar properties to those synthesized in the literature for longer times.In the second part, the effects of thermal/room temperature DMF purification on the MOF structure were investigated. The results showed no significant differences in PXRD analysis. However, the products subjected to thermal DMF stir wash exhibited a decrease in specific surface area and nitrogen adsorption capacity. Field emission scanning electron microscopy revealed the presence of smaller crystals in the MOFs treated with thermal stir wash. These results suggest that thermal DMF treatment can cause structural damage to the MOF.
This paper investigates the structural transformation process of aluminum metal-organic frameworks (MOFs) from amorphous to crystal. In the first part of this thesis, three different aluminum-based metal-organic frameworks (MOFs) were selected:MIL-53, MIL-100, and CAU-10. amorphous intermediates were synthesized at different reaction times, and the crystallization process was explored by using two solvent exchange (TOSE) and heat under vacuum (HEVA) to induce solvent removal and structural rearrangement. Powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FE-SEM), surface area and porosity analyzer, and thermal gravimetric analysis (TGA) were used to analyze the MOF structure, morphology, and adsorption performance. The results showed that MOF frameworks could be ordered through TOSE and HEVA. PXRD reveals the crystalline signals of a transition from amorphousto crystal, Moreover, products synthesized in shorten time exhibited similar properties to those synthesized in the literature for longer times.In the second part, the effects of thermal/room temperature DMF purification on the MOF structure were investigated. The results showed no significant differences in PXRD analysis. However, the products subjected to thermal DMF stir wash exhibited a decrease in specific surface area and nitrogen adsorption capacity. Field emission scanning electron microscopy revealed the presence of smaller crystals in the MOFs treated with thermal stir wash. These results suggest that thermal DMF treatment can cause structural damage to the MOF.
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雙溶劑置換, 加熱抽真空, 金屬有機骨架, Two solvent exchange, Heat under vacuum, Metal-Organic framework