Graetz Jason, Reilly James J
Department of Energy Sciences and Technology, Brookhaven National Laboratory, Upton, New York 11973, USA.
J Phys Chem B. 2005 Dec 1;109(47):22181-5. doi: 10.1021/jp0546960.
Aluminum hydride polymorphs (alpha-AlH3, beta-AlH3, and gamma-AlH3) were prepared by organometallic synthesis. Hydrogen capacities approaching 10 wt % at desorption temperatures less than 100 degrees C have been demonstrated with freshly prepared AlH3. The temperature-dependent rate constants were determined by measuring the isothermal hydrogen evolution between 60 degrees C and 140 degrees C. Fractional decomposition curves showed good fits using both the second and third-order Avrami-Erofeyev equations, indicating that the decomposition kinetics are controlled by nucleation and growth of the aluminum phase in two and three dimensions. The large activation energies measured for the AlH3 polymorphs suggest that the decomposition occurs via an activated complex mechanism with complexes consisting of approximately nine AlH3 molecules (1-2 unit cells for alpha-AlH3).
通过有机金属合成制备了氢化铝多晶型物（α-AlH₃、β-AlH₃和γ-AlH₃）。用新制备的AlH₃已证明在解吸温度低于100℃时氢容量接近10 wt%。通过测量60℃至140℃之间的等温析氢来确定温度依赖性速率常数。分数分解曲线使用二阶和三阶阿弗拉米-埃罗菲耶夫方程都显示出良好的拟合，表明分解动力学由铝相在二维和三维中的成核和生长控制。对AlH₃多晶型物测得的大活化能表明，分解通过活化络合物机制发生，络合物由大约九个AlH₃分子组成（α-AlH₃为1 - 2个晶胞）。
