Synthesis of Nanoflower-Shaped MXene Derivative with Unexpected Catalytic Activity for Dehydrogenation of Sodium Alanates

Surface group modification and functionalization of two-dimensional materials in many cases are deemed as effective approaches to achieve some distinctive properties. Herein, we present a new nanoflower-shaped TiO 2 /C composite which was synthesized by in situ alcoholysis of two-dimensional layered MXene (Ti 3 C 2 (OH x F 1– x ) 2 ) in a dilute HF solution (0.5 wt %) for the first time. Furthermore, it is demonstrated that it bestows a strong catalytic activity for the dehydrogenation of NaAlH 4 . The results show that the NaAlH 4 containing 10 wt % A 0.9 R 0.1 –TiO 2 /C (containing 90% anatase TiO 2 and 10% rutile TiO 2 ) composite merely took ∼85 min to reach a stable and maximum dehydrogenation capacity of ∼3.08 wt % at 100 °C, and it maintains stable after ten cycles, which is the best Ti-based catalyst for the dehydrogenation of NaAlH 4 reported so far. Theoretical calculation confirms that this C-doping TiO 2 crystals remarkably decreases desorption energy barrier of Al–H bonding in NaAlH 4, accelerating the breakdown of Al–H bonding. This finding raises the potential for development and application of new fuel cells.