Enhanced hydrogenation characteristics of Li-Mg-N-H system catalyzed with TiO2 nanoparticles; a mechanistic approach

The report describes the effect of TiO2 nano particles on the hydrogenation characteristics of promising Li-Mg-N-H hydrogen storage system. The effect of different particle size of TiO2 (200, 25 and 7 nm) on de/re-hydrogenation characteristics of Mg(NH2)2/LiH mixture has been investigated. Desorption kinetics of Li-Mg-N-H system with 25 nm TiO2 gets enhanced upto ∼25% as compared to the pristine material kinetics at 453 K (180 °C). The report also deals mechanistic approach for hydrogen release from Li-Mg-N-H system in the presence of TiO2 nanoparticles through XPS analysis of catalyzed sample at various stages of reaction. The XPS analysis confirms that during dehydrogenation nitrogen atom present in Li-Mg-N-H system share their lone pair electrons to Ti (present in TiO2) and provides an alternate decomposition path which has lower activation energy for dehydrogenation.