机械球磨固相化学反应制备AlH_3及其放氢性能  

Synthesis of AlH_3 by a Ball-Milling Solid-Phase Chemical Reaction and Its Hydrogen Desorption Properties

作　　者：罗永春[1,2] 毛松科[1] 阎汝煦[1] 孔令斌[1,2] 康龙[1] 

机构地区：[1]兰州理工大学材料科学及工程学院,兰州730050 [2]兰州理工大学甘肃省有色金属新材料省部共建国家重点实验室,兰州730050

出　　处：《物理化学学报》2009年第2期237-241,共5页Acta Physico-Chimica Sinica

基　　金：甘肃省自然科学基金(ZS032-B25-017);兰州理工大学博士基金资助项目

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.The synthesis of AlH3 with LiAlH4 and AlCl3 was 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 A1H3 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.

关 键 词：金属氢化物 机械球磨 AlH3 热分析放氢性能 

分 类 号：O614.31[理学—无机化学]