Ti-Zr催化剂对NaH/Al复合物可逆储氢特性的影响  

Influence of Ti-Zr Catalysts on Reversible Hydrogen Storage Characteristics of NaH/Al Composite

作　　者：肖学章[1] 陈立新[1] 范修林[1] 葛红卫[1] 李寿权[1] 应窕[1] 王新华[1] 陈长聘[1] 

机构地区：[1]浙江大学材料科学与工程学系,杭州310027

出　　处：《物理化学学报》2008年第3期423-427,共5页Acta Physico-Chimica Sinica

基　　金：国家重点基础研究发展计划(2007CB209701);国家自然科学基金重点项目(50631020);新世纪优秀人才支持计划(NCET-07-0741)资助

摘　　要：采用机械球磨(NaH/Al+Ti)和(NaH/Al+Ti-Zr)复合物的方法加氢制备了NaAlH4配位氢化物,系统研究了Ti、Ti-Zr催化剂以及不同加氢条件对其可逆储氢行为的影响.结果表明,对于NaH/Al体系的吸放氢性能,共掺金属Ti粉/Zr粉的催化作用比单独掺金属Ti粉的催化作用要好.随着加氢温度从85℃上升到140℃,体系的吸氢容量先增后减,并在120℃时达到最大值;同时,发现共掺Ti-Zr催化剂的复合物具有最佳的储氢性能,在120和85℃时的吸氢量分别为4.61%和3.52%(w),比仅掺Ti催化剂的复合物分别高出0.40%和0.70%(w)的吸氢量.随着加氢压力的增大,(NaH/Al+Ti-Zr)复合物的吸氢性能随之提高.XRD和DSC分析结果表明,NaAlH4体系的放氢过程明显发生两步分解反应,共掺Ti-Zr催化剂的复合物储氢性能优于单独掺Ti催化剂的原因是,共掺催化剂能有效改善NaAlH4体系吸放氢反应的动力学性能,并降低体系的放氢温度.The NaAlH4 complex hydride was prepared by hydrogenation of the ball-milled （NaH/Al＋Ti） and （Nail/ Al＋Ti-Zr） composites. The influences of Ti and Ti-Zr catalysts, different hydriding temperatures and pressures on its reversible hydrogen storage behaviors were investigated. It was found that the catalysis of Ti-Zr powders as cocatalysts on the dehydriding/hydriding characteristics of Nail/Al was better than that of Ti alone as catalyst. As the hydriding temperature increased from 85 ℃ to 140 ℃, the hydrogen absorption capacity increased first and then decreased, and reached the highest value at 120℃. The composite co-doped with Ti-Zr catalysts had the best reversible hydrogen storage properties, its hydrogen storage capacities were 4.61%（w） at 120 ℃and 3.52%（w） at 85 ℃, which were 0.40% and 0.70% （w） higher than that doped with Ti alone as catalyst in the same hydriding condition, respectively. The hydrogen storage performance of （NaH/Al＋Ti-Zr） composite was enhanced with the increase of hydriding pressure. XRD and DSC analyses showed that the dehydriding process of NaAlH4 system took place in two steps. The composite co-doped with Ti-Zr catalysts could improve the dehydriding/hydriding kinetics of NaAlH4 system and reduced its dehydriding temperature. That was the main reason of the hydrogen storage characteristic of the composites co-doped with Ti-Zr catalysts better than that doped with Ti catalyst alone.

关 键 词：配位氢化物 NaAlH_4 掺Ti-Zr 球磨 储氢性能 

分 类 号：TK91[动力工程及工程热物理]