Dehydriding and rehydriding processes of well-crystallized Mg(BH4)2 accompanying with formation of intermediate compounds
✍ Scribed by H.-W. Li; K. Kikuchi; Y. Nakamori; N. Ohba; K. Miwa; S. Towata; S. Orimo
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 290 KB
- Volume
- 56
- Category
- Article
- ISSN
- 1359-6454
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✦ Synopsis
Dehydriding and rehydriding properties of well-crystallized Mg(BH 4 ) 2 were systematically investigated by thermogravimetry (TG) and pressure-composition-temperature (PCT) measurements. The dehydriding reaction of Mg(BH 4 ) 2 starts at approximately 500 K, and about 14.4 mass% of hydrogen is desorbed according to the following multi-step reaction:
The apparent enthalpy change in the dehydriding reaction from Mg(BH 4 ) 2 to MgH 2 is estimated to be 57 ± 5 kJ mol À1 H 2 based on the result of the PCT measurement. It is proved that approximately 6.1 mass% of hydrogen can be reversibly stored for the sample of Mg(BH 4 ) 2 after the dehydriding reaction, through the formation of a possible intermediate compound such as MgB 12 H 12 .