SrAl_2合金的储氢动力学性能

Hydrogen Storage Kinetics of SrAl_2 Alloy

研究了在Zintl相SrAl2合金中添加不同金属氯化物催化剂后的相结构和吸氢动力学性能。XRD分析表明,合金吸氢前仍然为SrAl2相,催化剂由于含量较少未被检测出;吸氢后,合金相结构根据催化剂添加种类的不同分为以下两种情况:氢化程度高的样品,由SrAl2H2、SrAl4和SrH2三相组成;氢化程度低的样品,由SrAl2H2、SrAl4、SrH2和未反应的SrAl2四个相组成。储氢性能研究表明,添加金属氯化物催化剂能够有效改善SrAl2合金的吸氢动力学性能。吸氢动力学机理分析表明,SrAl2合金吸氢控制步骤为表面化学反应,而添加催化剂使得合金的吸氢控制步骤转变为三维扩散。

Crystal structure and hydrogenation kinetics of the Zintl phase SrAl2 doped with various metal chlorides were studied.X-ray diffractometry（XRD） results indicate the alloy is composed of SrAl2 phase regardless of the doped catalyst.After hydrogenation,the alloy either consists of SrAl2H2,SrAl4 and SrH2,or consists of SrAl2H2,SrAl4,SrH2 and unreacted SrAl2 depending on the type of catalyst.Hydrogenation measurements show that the hydrogen absorption kinetics of the SrAl2 alloy is improved effectively by doping with metal chlorides.Hydrogenation mechanism analysis reveals that the control step for hydrogenation of the SrAl2 alloy is surface chemical reaction,while it changes to 3D diffusion for the alloy after adding catalyst.