Key Laboratory of Air-driven Equipment Technology of Zhejiang Province, Quzhou University, Quzhou 324000, China.
Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310058, China.
Molecules. 2019 May 15;24(10):1861. doi: 10.3390/molecules24101861.
A detailed analysis of the dehydrogenation mechanism of LiBH/LiAlH ( = 0.5, 1, 2) composites was performed by thermogravimetry (TG), differential scanning calorimetry (DSC), mass spectral analysis (MS), powder X-ray diffraction (XRD) and scanning electronic microscopy (SEM), along with kinetic investigations using a Sievert-type apparatus. The results show that the dehydrogenation pathway of LiBH/LiAlH had a four-step character. The experimental dehydrogenation amount did not reach the theoretical expectations, because the products such as AlB and LiAl formed a passivation layer on the surface of Al and the dehydrogenation reactions associated with Al could not be sufficiently carried out. Kinetic investigations discovered a nonlinear relationship between the activation energy (E) of dehydrogenation reactions associated with Al and the ratio , indicating that the E was determined both by the concentration of Al produced by the decomposition of LiAlH and the amount of free surface of it. Therefore, the amount of effective contact surface of Al is the rate-determining factor for the overall dehydrogenation of the LiBH/LiAlH composites.
通过热重分析（TG）、差示扫描量热法（DSC）、质谱分析（MS）、粉末 X 射线衍射（XRD）和扫描电子显微镜（SEM），以及使用 Sievert 型装置进行的动力学研究，对 LiBH/LiAlH（=0.5、1、2）复合材料的脱氢机理进行了详细分析。结果表明，LiBH/LiAlH 的脱氢途径具有四步特征。实验脱氢量未达到理论预期，因为 AlB 和 LiAl 等产物在 Al 表面形成钝化层，与 Al 相关的脱氢反应无法充分进行。动力学研究发现，与 Al 相关的脱氢反应的活化能（E）与比值之间存在非线性关系，表明 E 既由 LiAlH 分解产生的 Al 的浓度决定，也由其自由表面的量决定。因此，Al 的有效接触表面积的量是 LiBH/LiAlH 复合材料整体脱氢的速率决定因素。
