Interfacial Engineering of Fluorinated TiO Nanosheets with Abundant Oxygen Vacancies for Boosting the Hydrogen Storage Performance of MgH.

The interaction between fluorinated surface in the partially reduced nano-crystallite titanium dioxide (TiO(F)) and MgH is studied for the first time. Compared with pristine MgH (416 °C), the onset desorption temperature of MgH+5 wt.% TiO(F) composite can be dramatically lowered to 189 °C. In addition, the composite exhibits remarkable dehydrogenation kinetics, which can release 6.0 wt.% hydrogen thoroughly within 6 min at 250 °C. The apparent activation energy for dehydriding is decreased from 268.42 to 119.96 kJ mol. Structural characterization and theoretical calculations indicate that the synergistic effect between multivalent Ti species, and the in situ formed MgF and MgFH is beneficial for improving the hydrogen storage performance of MgH. Moreover, oxygen vacancies can accelerate the electron transportation and facilitate hydrogen diffusion. The study provides a novel perspective on the modification of MgH by fluorinated transition metal oxide catalyst.