镨、钕氢化物催化剂对NaH/Al复合物吸放氢性能的影响  

Effect of Praseodymium and Neodymium Hydride Catalysts on Hydrogen Storage Properties of NaH/Al Composite

作　　者：吴哲[1] 肖学章[1] 俞凯嵘[1] 范修林[1] 李寿权[1] 陈立新[1] 

机构地区：[1]浙江大学材料科学与工程学系,浙江杭州310027

出　　处：《中国稀土学报》2010年第2期242-246,共5页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金项目(50871099);新世纪优秀人才支持计划项目(NCET-07-0741);中国博士后科学基金项目(20080440196)资助

摘　　要：采用NaH和Al为合成原料,镨、钕氢化物为催化剂,通过机械球磨(NaH/Al+6%(摩尔分数)RE-H)(RE=Pr,Nd)复合物的方法并加氢合成NaAlH4络合氢化物,系统研究了催化剂对其吸放氢性能的影响。结果表明,加入PrH2.92和NdH2.27能明显改善NaH/Al复合物的吸放氢动力学性能,有效降低NaAlH4的脱氢温度。(NaH/Al+6%PrH2.92)和(NaH/Al+6%NdH2.27)复合物的120℃吸氢容量分别为3.57%和3.61%(质量分数),170℃放氢容量分别为2.57%和2.95%;且两者均具有较好的吸放氢循环稳定性,但吸(放)氢后样品中均存在少量Na3AlH6相,表明样品的吸(放)氢反应进行得并不彻底,使得其实际吸放氢容量低于理论可逆储氢容量。研究表明,PrH2.92和NdH2.27在球磨、吸/放氢过程中始终稳态存在,起着催化储氢作用;(NaH/Al+6%PrH2.92)复合物的放氢活化能稍低于(NaH/Al+6%NdH2.27)复合物。NaAlH4 complex hydrides doped with lanthanon hydrides were prepared by hydrogenation of the ball-milled（NaH/Al＋6%RE-H） composites（RE=Pr,Nd） using NaH and Al powder as raw materials,PrH2.92 and NdH2.27 powder as catalysts.The influence of catalyst on the hydriding and dehydriding behaviors of the synthesized composites was investigated.The results showed that the doping PrH2.92 and NdH2.27 could improve obviously the hydriding/dehydriding kinetics of NaH/Al composite and lower the dehydriding temperatures of sodium aluminum hydride.The hydrogen absorption capacities of（NaH/Al＋6%PrH2.92） and（NaH/Al＋6%NdH2.27） composites were 3.57% and 3.61% at 120 ℃,and their hydrogen desorption capacities were 2.57% and 2.95% at 170 ℃,respectively.These two composites had good de/hydriding cycling stabilities.However,the remains of Na3AlH6 phase in the hydrided and dehydrided composite samples indicated the incompletion of the hydriding/dehydriding reactions,resulting in the difference between the factual de/hydriding capacities and theoretical reversible hydrogen storage capacities.It was also found that PrH2.92 and NdH2.27 as catalysts were stable in the milling/hydriding/dehydriding processes.The（NaH/Al＋6%PrH2.92） composite had less dehydriding activation energy than the（NaH/Al＋6%NdH2.27） composite.

关 键 词：NaAlH4 镨氢化物 钕氢化物 催化作用 吸放氢性能 稀土 

分 类 号：O643.3[理学—物理化学]