Laboratory for Hydrogen & Energy, Empa Materials Science and Technology, Uberlandstrasse 129, 8600 Dübendorf, Switzerland.
Phys Chem Chem Phys. 2010 Sep 28;12(36):10950-5. doi: 10.1039/c000299b. Epub 2010 Jul 26.
The surface oxidation behavior of LiBH(4) and NaBH(4) was investigated in view of the formation and structure of the surface oxidation and its effect on the hydrogen desorption kinetics. The sample surfaces were intentionally modified by exposure to oxygen in the pressure range from 10(-10) mbar up to 200 mbar. The induced surface changes were systematically studied by means of X-ray photoelectron spectroscopy. NaBH(4) shows a low reactivity with oxygen, while LiBH(4) oxidizes rapidly, accompanied by surface segregation of Li. The hydrogen desorption kinetics of LiBH(4) were studied by thermal desorption spectroscopy with particular emphasis on the analysis of the desorbed gases, i.e. diborane and hydrogen. The surface oxidation induces the formation of a Li(2)O layer on LiBH(4), significantly reduces the desorption of diborane, and enhances the rate of hydrogen desorption.
研究了 LiBH（4）和 NaBH（4）的表面氧化行为，以期了解表面氧化的形成和结构及其对氢气脱附动力学的影响。通过将样品暴露于压力范围为 10（-10）至 200 mbar 的氧气中，对样品表面进行了有意的修饰。利用 X 射线光电子能谱系统地研究了诱导的表面变化。NaBH（4）与氧气的反应活性低，而 LiBH（4）则迅速氧化，伴随着 Li 的表面偏析。通过热脱附光谱法研究了 LiBH（4）的氢气脱附动力学，特别强调了对脱附气体（即二硼烷和氢气）的分析。表面氧化在 LiBH（4）上诱导形成 Li（2）O 层，显著降低了二硼烷的脱附，并提高了氢气的脱附速率。
