Reversible hydrogen storage properties of NaAlH4 enhanced with TiN catalyst

Hydrogen storage properties of commercial NaAlH4 doped efficient TiN catalyst have been systematically investigated. The dehydrogenation and reversibility of the 2 mol% TiN-doped NaAlH4 (2%TiN-NaAlH4) system have been studied. It is found that TiN catalyst improves the dehydrogenation kinetics and decreases the dehydrogenation temperature of NaAlH4. Interestingly, the onset dehydrogenation temperature of 2%TiN-NaAlH4 system gets lowered to about 130.0 °C with a faster kinetics, and the dehydrogenation rate reaches a maximum value at 183.5 °C. The apparent activation energy for the first and the second dehydrogenation step of TiN-NaAlH4 system is estimated to be 91.70 kJ mol−1 and 99.93 kJ mol−1, respectively. The dehydrogenation and hydrogenation behaviors of 2%TiN-NaAlH4 are investigated under different hydrogen pressures using high-pressure differential scanning calorimetry (HP-DSC). The 2%TiN-NaAlH4 system exhibits excellent reversibility at moderate conditions. Moreover, the dehydrogenation and hydrogenation processes of the 2%TiN-NaAlH4 system are also discussed.