Enhanced hydrogen storage performances of NaBH4–MgH2 system
Enhanced hydrogen storage performances of NaBH4–MgH2 system
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DOI：
10.1016/j.jallcom.2009.01.012
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发表时间：
2009-06
影响因子：
6.2
通讯作者：
Jianfeng Mao;Xuebin Yu;Zaiping Guo;Huakun Liu;Zhongdao Wu;J. Ni
中科院分区：
文献类型：
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作者：
Jianfeng Mao;Xuebin Yu;Zaiping Guo;Huakun Liu;Zhongdao Wu;J. Ni
研究了2NaBH_4 + MgH_2体系的储氢性能。研究发现，MgH 2的存在会使NaBH 4的分解不稳定，使其脱氢温度比纯NaBH 4降低约40°C。据信，在脱氢时形成MgB 2使脱氢状态稳定，从而使NaBH 4不稳定。对于解吸，观察到以下两步反应：2NaBH 4 + MgH 2 → 2NaBH 4 +Mg+ H 2 →2NaH+ MgB 2 + 4 H 2。此外，还对NaBH_4-MgH_2体系进行了TiF_3、TiO_2、Zr、Si和BCC合金等催化剂的掺杂研究。在这些催化剂中，TiF 3在快速动力学和降低NaBH 4-MgH 2体系的脱氢温度方面表现出最佳的行为。在600°C、初始氢压约4 MPa的条件下，研究了TiF 3掺杂的NaBH 4-MgH 2体系的再氢化反应。结果表明，5.89wt.%氢气在12小时内再氢化。XRD结果表明，再氢化样品中有NaBH 4和MgH 2生成。
The hydrogen storage properties of 2NaBH4+MgH2system were studied. It was found that the presence of MgH2could destabilize the decomposition of NaBH4, decreasing the dehydrogenation temperature about 40°C compared with the pure NaBH4. It is believed that the formation of MgB2upon dehydrogenation stabilizes the dehydrogenated state and, thereby, destabilizes the NaBH4. For the desorption the following two-step reaction was observed: 2NaBH4+MgH2→2NaBH4+Mg+H2→2NaH+MgB2+4H2. Furthermore, various catalysts such as TiF3, TiO2, Zr, Si and BCC alloy were doped to the NaBH4–MgH2system. Among these catalysts, TiF3exhibited the optimum behavior in terms of fast kinetics and lowering the dehydrogenation temperature of the NaBH4–MgH2system. The rehydrogenation experiments of TiF3-doped NaBH4–MgH2system were investigated at 600°C with an initial hydrogen pressure of about 4MPa. It showed that 5.89wt.% hydrogen was rehydrogenated within 12h. XRD results demonstrated the formation of NaBH4and MgH2in the rehydrogenated sample.