Influence of TiC catalyst on absorption/desorption behaviors and microstructures of sodium aluminum hydride

TiC-doped NaAlH4 complex hydrides were prepared by hydrogenation of ball-milled NaH/Al mixture with x TiC powder (x = 0, 5%, 8%, 10%, mole fraction). The effects of TiC catalyst content on the absorption/desorption behaviors of the samples were investigated. The results show that TiC can improve the hydriding/dehydriding kinetics of sodium aluminum hydride, the hydriding rate of the sample increases with increasing TiC content. It is found that the TiC-doped NaAlH4 composites have a relatively good cyclic stability. The composite doped with 10% TiC maintains steadily about 4.5% (mass fraction) hydrogen absorption capacity as against about 3.8% (mass fraction) hydrogen desorption capacity over 8 cycles. The particle sizes of the TiC-doped NaAlH4 composites can be reduced to 50-100 nm, which may play an important role in improving the hydriding/dehydriding kinetics.