Direct synthesis and dehydrogenation properties of NaAlH_4 catalyzed with ball-milled Ti–B  

作　　者：Li Li Zi-Chao Zhang Yi-Jing Wang Li-Fang Jiao Hua-Tang Yuan 

机构地区：[1]Laboratory of Inorganic Functional Materials, School of Materials Science and Engineering, University of Jinan [2]Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Key Laboratory of Advanced Energy Materials Chemistry (MOE), College of University, Nankai University

出　　处：《Rare Metals》2017年第6期517-522,共6页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China (Nos. 51501072 and 51471089);the Excellent Young and Middle-aged Scientists of Shandong Province (No.BS2014CL026);the Doctoral Foundation of University of Jinan (No.XBS1448);the Key Laboratory of Advanced Energy Materials Chemistry (No.IRT-13R30)

摘　　要：Ball-milled Ti-B-doped sodium aluminum hydride was directly synthesized via mechanical ball-milling of a NaH/Al mixture. The mixture was completely hydrogenated to NaAlH4 after 70 h under hydrogen pressure of 1 MPa. And higher hydrogen pressure is beneficial for the conversion from NaH/Al mixture to NaAlH4. The dehydrogenation properties of the as-synthesized Ti-Bdoped sodium aluminum were systematically investigated.The result shows that ball-milled Ti-B has a remarkable catalytic effect on the enhanced dehydrogenation properties of NaAlH4. As-synthesized Ti-B-doped NaAlH_4 sample releases hydrogen at the temperature of about 100 ℃. Approximately 4.15 wt% H2 is released from ballmilled Ti-B-doped NaAlH_4 at 233.7 ℃. Even at 110 ℃, it also releases about 2.83 wt% hydrogen. The apparent activation energy（E_a） for the first step is estimated to be 83.97 k J·mol^-1 using Arrhenius equation. Thus, utilization of ball-milled Ti-B as catalyst would substantially enhance the practical applications of NaAlH_4 for hydrogen storage.Ball-milled Ti-B-doped sodium aluminum hydride was directly synthesized via mechanical ball-milling of a NaH/Al mixture. The mixture was completely hydrogenated to NaAlH4 after 70 h under hydrogen pressure of 1 MPa. And higher hydrogen pressure is beneficial for the conversion from NaH/Al mixture to NaAlH4. The dehydrogenation properties of the as-synthesized Ti-Bdoped sodium aluminum were systematically investigated.The result shows that ball-milled Ti-B has a remarkable catalytic effect on the enhanced dehydrogenation properties of NaAlH4. As-synthesized Ti-B-doped NaAlH_4 sample releases hydrogen at the temperature of about 100 ℃. Approximately 4.15 wt% H2 is released from ballmilled Ti-B-doped NaAlH_4 at 233.7 ℃. Even at 110 ℃, it also releases about 2.83 wt% hydrogen. The apparent activation energy（E_a） for the first step is estimated to be 83.97 k J·mol^-1 using Arrhenius equation. Thus, utilization of ball-milled Ti-B as catalyst would substantially enhance the practical applications of NaAlH_4 for hydrogen storage.

关 键 词：Hydrogen storage material NaAlH4 Ti-B DEHYDROGENATION 

分 类 号：TB34[一般工业技术—材料科学与工程]