Improved dehydrogenation of TiF3-doped NaAlH4 using ordered mesoporous SiO2 as a codopant

A study of the influence of mesoporous SiO2 on the dehydrogenation of NaAlH4 and TiF3-doped NaAlH4 revealed that the amount of hydrogen evolved is 3.8 wt% for the pristine NaAlH4 and around 4.2 wt% for the TiF3-doped NaAlH4, but increases to 4.9–5.0 wt% once the samples are doped with mesoporous SiO2 in the temperature range of 100–350 °C. A favorable synergistic effect on the NaAlH4 dehydrogenation is achieved as mesoporous SiO2 is added as a codopant along with TiF3, which is associated with the nanosized pores and high specific surface area of mesoporous SiO2. The catalytic mechanism of mesoporous SiO2 is more physical than chemical relative to the catalytic mechanism of TiF3.