Catalytic nanoconfinement effect of in-situ synthesized Ni-containing mesoporous carbon scaffold (Ni-MCS) on the hydrogen storage properties of LiAlH_4

摘要

We demonstrate in-situ synthesis of homogeneously dispersed Ni-containing mesoporous carbon scaffold (Ni-MCS) for improving dehydrogenation kinetics of LiAlH_4 (hereafter denoted as LAH). LAH was impregnated into Ni-MCS scaffold (LAH confined-Ni-MCS) and also into pure mesoporous carbon scaffold (MCS) (LAH confined-MCS). The XRD patterns of LAH confined in Ni-MCS system indicate its amorphous nature, while ~(27)Al MAS NMR spectroscopy confirmed the nanoconfinement of LAH in the Ni-MCS system. TPD-MS demonstrated the released of H_2 at 66 ℃ for the LAH confined-Ni-MCS system, with 84 ℃ reduction of the onset desorption temperature (T_(onset)) as compared to the pure LAH. The H_2 desorption from LAH confined-Ni-MCS is about 6.19 wt% H_2. This strategy enables the exertion of nanoconfinement, Ni catalyst and compartmentalization effects over the growth of particle size and aggregation, which also significantly contributed to reduce the activation energy (Ea) (39.67 kJ/mol) of the system.