氫化鋁鋰 (LiAlH4)具有很高的氫密度，是極具潛力的儲氫材料。因此本研究嘗試改善氫化鋁鋰的放氫特性。實驗過程中分別添加各式碳材、複合觸媒及其他各式催化劑與氫化鋁鋰相互球磨，並利用熱程控脫附儀 (TPD)進行放氫實驗分析。實驗結果發現以超臨界二氧化碳(scCO2)合成之鐵/石墨烯複合觸媒擁有最佳的催化放氫性質，且效果也優於文獻上最佳的催化劑氯化釩 (VCl3)及二氧化鈦 (TiO2)。後續進行材料分析發現，此複合觸媒經由超臨界製程後，形成奈米級的鐵均勻分布於片狀的石墨烯上；與傳統化學沉積法所看到的團聚現象有顯著差異。因此尺寸效應與分布為影響催化放氫性質的重要因素。 本研究後續進行了100 oC恆溫放氫動力學研究，從實驗結果發現經球磨30分鐘後之氫化鋁鋰需10.8小時才能達到4 wt%放氫量，而添加了10 wt%鐵/石墨烯複合觸媒後，僅需10分鐘便能達到相同的放氫量。根據本研究之結果，藉由超臨界二氧化碳所合成之鐵/石墨烯複合觸媒能最有效的改善氫化鋁鋰放氫性質。 Lithium aluminum hydride (LiAlH4)has high hydrogen density so it’s a potential hydrogen storage materials. In this study, we tried to improve the hydrogen storage properties of LiAlH4 by ball milling process. We introduced different carbon materials, metal/carbon composites, other catalysts. According to Temperature-Programmed Desorption (TPD)analysis, We found that by Supercritical carbon dioxide (scCO2)process synthesized Fe/Graphene composites obviously decreased the dehydrogenation temperature of LiAlH4. It’s catalytic effect better than VCl3, TiO2. By the materials analysis, between air process and scCO2 process, the later is more monodisperse than air process. So size effect and distribution play the most important role to improve catalytic properties. At 100 oC isothermal dehydrogenation dynamics analysis, LiAlH4 (BM30 min)release 4 wt% hydrogen after 10.8 hr while LiAlH4 + 10 wt% Fe/Graphene only need 10 minute. The results of experimental indicate that the Fe/Graphene is the best catalyst for LiAlH4.
