Reversible hydrogen storage via titanium-catalyzed LiAlH4 and Li3AlH6
Reversible hydrogen storage via titanium-catalyzed LiAlH4 and Li3AlH6
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DOI：
10.1021/jp012127w
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发表时间：
2001-11-15
影响因子：
3.3
通讯作者：
Sakai, T
中科院分区：
文献类型：
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作者：
Chen, J;Kuriyama, N;Sakai, T
振动研磨技术可以通过使试剂在制备规模上紧密接触并提供额外的机械能来激活反应体系，比众所周知的球磨方法更有效，用于制备氯化钛（III）（TiCl（3）（.）1/3AlCl（3））掺杂的四氢铝酸锂（LiAlH4）和六氢铝酸锂（Li3AlH6）粉末纳米晶体。利用X射线衍射（XRD）、扫描电子显微镜（SEM）、热重分析（TG）和差示扫描量热分析（DSC）对相结构和脱氢/再氢化性能进行了表征。通过X射线光电子能谱（XPS）研究了可逆脱氢和再氢化的机理。热力学和动力学测量显示，在 25-250 摄氏度的温度范围内，脱氢/再氢化反应发生了明显的变化。从氢解吸动力学的阿伦尼斯图可以看出，LiAlH4 和 Li3AlH6 氢化物分解的表观活化能分别为 42.6 和 54.8 kJ/mol H-2。基于可逆储氢性质和催化功能的结果表明，均匀分布的Ti催化纳米晶复合氢化物和具有Ti-0双左右箭头Ti3+（Ti-0/Ti2+/Ti3+）缺陷位点的Ti催化剂在优化可逆储氢方面发挥着重要作用。
A vibrating-mill technique, which can activate the reaction system by bringing the reagents into very close contact at the preparative scale and by providing extra mechanical energy, much more effectively than the well-known ball-milling method, was used to prepare titanium(III) chloride (TiCl(3)(.)1/3AlCl(3))-doped lithium tetrahydridoaluminate (LiAlH4) and lithium hexahydridoaluminate (Li3AlH6) powders with nanocrystallites. The phase structure and dehydriding/rehydriding properties were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetry (TG), and differential scanning calorimetry (DSC). The mechanism of reversible dehydrogenation and rehydrogenation was examined by means of X-ray photoelectron spectroscopy (XPS). Thermodynamic and kinetic measurements showed a distinct change for the dehydriding/rehydriding reactions over the temperature range 25-250 degreesC. From the Arrhenius plot of hydrogen desorption kinetics, apparent activation energies were found to be 42.6 and 54.8 kJ/mol H-2 for the hydride decompositions of LiAlH4 and Li3AlH6, respectively. The results based on the properties of reversible hydrogen storage and catalysis function indicate that both the homogeneous distribution of Ti-catalyzed nanocrystalline complex hydrides and the Ti-catalyst with a Ti-0 double left right arrow Ti3+ (Ti-0/Ti2+/Ti3+) defect site play important roles in optimizing the reversible hydrogen storage.