Thermally induced in situ fabrication of TiO2/CN heterojunction dopant for enhancement of hydrogen storage properties of LiAlH4.

• TiO 2 /CN heterojunction is successfully prepared via one-step calcination with bubble template assisted. • The LiAlH 4 -7 wt% TiO 2 /CN starts to release hydrogen at 76 °C and releases 4.9 wt% H 2 at 120 °C within 50 min. • The heterojunction can generate internal electric field and lower the energy barrier to optimize the movement of electrons. • The in situ formed AlTi 3 N can weaken the Al-H bonds in LiAlH 4 through interfacial charge transfer. Herein, a novel TiO 2 /CN heterojunction material has been prepared by one-step bubble template-assisted calcination to enhance the hydrogen storage capability of LiAlH 4. The TEM, XPS and UPS analysis confirm that a heterostructure is formed between TiO 2 and g-C 3 N 4 successfully. The experimental findings indicate that the TiO 2 /CN significantly enhances the dehydrogenation performance of LiAlH 4. For instance, the LiAlH 4 -7 wt% TiO 2 /CN starts to dehydrogenize at 76 °C (94 °C less than pure LiAlH 4) and releases 6.5 wt% H 2 at 200 °C. Meanwhile, LiAlH 4 -7 wt% TiO 2 /CN releases 4.9 wt% H 2 at 120 °C within 50 min. The mechanism analysis illustrates that AlTi 3 N is formed in situ during ball-milling. And density functional theory (DFT) calculation results reveal that the AlTi 3 N can weaken the Al-H bonds in LiAlH 4 through interfacial charge transfer. Furthermore, the TiO 2 /CN heterostructure creates an internal electric field that generates an electron-rich layer. As a result, the negative electron layer at one end of the TiO 2 /CN heterojunction has an increased affinity for H, which enhances the dehydrogenation reaction of LiAlH 4. Clearly, both the TiO 2 /CN heterostructure and AlTi 3 N contribute to the improvement of the dehydrogenation properties of LiAlH 4. [Display omitted] [ABSTRACT FROM AUTHOR]