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.
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)
