NaAlH4 complex hydrides doped with lanthanon hydrides were prepared by hydrogenation of the ball-milled NaH/Al+ xmol.% RE-H composites (RE=La,Ce;x=2,4,6) using NaH and Al powder as raw materials. The influence of lanthanon hydride catalysts on the hydriding and dehydriding behaviors of the as-synthesized composites were investigated. It was found that the composite doped with 2 mol.% LaH3.01 displayed the highest hydrogen absorption capacity of 4.78 wt.% and desorption capacity of 4.66 wt.%, respectively. Moreover, the composite doped with 6 mol% CeH 2.51 showed the best hydriding/dehydriding reaction kinetics. The proposed catalytic mechanism for reversible hydrogen storage properties of the composite was attributed to the presence of active LaH3.01 and CeH2.51 particles, which were scattering on the surface of NaH and Al particles, acting as the catalytic active sites for hydrogen diffusion and playing an important catalytic role in the improved hydriding/dehydriding reaction.
结合球磨和热处理制备掺杂Ti,TiMn_2和TiAl的Mg_2FeH_6样品,并系统研究这些添加剂对Mg_2FeH_6样品放氢行为的影响。研究结果表明:所有添加剂都能够在一定程度上改善Mg_2FeH_6的放氢性能,特别是TiMn_2对Mg_2FeH_6的放氢动力学性能改善效果显著。根据Kissinger方程计算出掺杂TiMn_2的Mg_2FeH_6样品的放氢活化能为94.87 k J/mol,与未掺杂的Mg_2FeH_6样品相比,降低了28 kJ/mol。另外,掺杂TiMn_2的Mg_2FeH_6样品在循环测试过程中仍具有良好的放氢性能改善效果。
