LiAlH4 supported on TiO2/hierarchically porous carbon nanocomposites with enhanced hydrogen storage properties

We report the synthesis of LiAlH4 supported on TiO2/hierarchically porous carbon (LAH-TiO2/HPC) nanocomposites using a one-step solvent method and their enhanced catalytic dehydrogenation performance. The as-prepared TiO2/HPC nanocomposites show that TiO2 nanoparticles (similar to 10 nm) are homogeneously distributed on the surface of hierarchically porous carbon (HPC). The results show that TiO2/HPC nanocomposites exhibit better catalytic performance for the dehydrogenation of LiAlH4 and rehydrogenation of the dehydrided sample than that of TiO2 nanoparticles and HPC. The dehydrogenation temperature of 37LAH-25TiO(2)/38HPC with 37 wt% LiAlH4, 25 wt% TiO2 and 38 wt% HPC is the lowest. Hydrogen started to be released at 64 degrees C, which is about 100 degrees C lower than that of pure LiAlH4. In addition, 4.3 wt% of hydrogen could be released from 37LAH-25TiO(2)/38HPC within 40 min at 130 degrees C, indicating fast kinetics with an activation energy of 47.1 +/- 3.5 kJ mol(-1). Furthermore, it can re-adsorb H-2 at 300 degrees C under a hydrogen pressure of 4 MPa. The nanoconfinement of LiAlH4 into hierarchically porous carbon with high surface areas and the high distribution of TiO2 nanoparticles with a Ti(4+)/Ti(3+)/Ti(2+) defect site play a synergistic role in improving the hydrogen storage properties of LiAlH4.