Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7718370 | International Journal of Hydrogen Energy | 2014 | 7 Pages |
Abstract
In this work, the complex hydrogen sorption behaviors in a 3NaBH4/HoF3 composite prepared through mechanical milling were carefully investigated, including the reactions occurred during ball milling and de-/rehydrogenation processes. Different from other rear earth fluorides, the HoF3 can react with NaBH4 during ball milling, leading to the formations of Na-Ho-F and Na-Ho-BH4 complex compounds. The first dehydriding of the 3NaBH4/HoF3 composite can be divided into 4 steps, including the ion exchange between Hâ and Fâ, the formation of NaHo(BH4)4, the decomposition of NaHo(BH4)4 and reaction of NaBH4 with Na-Ho-F compounds. The final products, HoB4, HoH3 and NaF, can be rehydrogenated to generate NaBH4 and NaHoF4 with an absorption capacity of 2.3 wt% obtained at 400 °C. Based on the Pressure-Composition-Temperature measurements, the de-/rehydrogenation enthalpies of the 3NaBH4/HoF3 composite are determined to be 88.3 kJ molâ1 H2 and â27.1 kJ molâ1 H2, respectively.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Lina Chong, Jianxin Zou, Xiaoqin Zeng, Wenjiang Ding,