【摘要】 以LiAlH4和AlCl3为原料,采用机械球磨固相化学反应方法制备了铝氢化合物,通过X射线衍射(XRD)、热分析(TG-DSC)和质谱(MS)分析等方法对反应产物进行分析和表征,研究了不同球磨时间(4、8、15和20h)对LiAlH4+AlCl体系的固相反应转变规律﹑合成产物和放氢性能的影响.研究结果表明,随球磨时间的增加,球磨固相反应按3LiAlH4+AlCl3→4AlH3+3LiCl方向进行,形成了非晶态铝氢化合物AlH3,球磨20h时反应基本完全.球磨产物的放氢动力学特性随球磨时间增加而改善,其放氢起始温度均低于100℃,最大放氢量达到2.6%-3.6%(H2)(w),接近反应体系的理论储氢量4.85%(H2)(w).球磨过程中反应产物形成LiCl·H2O以及少量AlH3发生分解是影响球磨产物最大放氢量的主要因素.更多还原

【Abstract】 The synthesis of AlH3with LiAlH4and AlCl3was done by ball-milling solid phase chemical reaction under H2 atmosphere. The effects of different milling times (4-20 h) on the solid state chemical reaction and dehydrogenation properties of the milled mixture were investigated comprehensively using X-ray diffraction (XRD), thermal analysis (TG-DSC), mass spectroscopy (MS), scanning electron microscopy (SEM), and dehydrogenation measurements. The milled reaction was found to proceed as follows: 3LiAlH4+AlCl3→4AlH3+3LiCl. The reaction was almost complete after milling for 20 h and amorphous AlH3 was formed. With an increase in milling time dehydrogenation kinetics was improved resulting in hydrogen desorption at a temperature lower than 100 ℃. The maximum desorbed hydrogen capacities reached 2.6%-3.6% (w), which is close to the theoretical capacity of 4.85% (w) for the reaction. A decrease in the maximum desorbed hydrogen capacity can be attributed to the formation of LiCl·H2O and also to the decomposition of AlH3 during the milling process.更多还原