Graphene-Supported Sc₂O₃/TiO₂ for Superior Catalysis on Hydrogen Sorption Kinetics of MgH₂

Complex metal oxide catalysts greatly accelerate the hydrogen sorption rates in the magnesium hydride system. In this study, the graphene-supported Sc₂O₃/TiO₂ catalyst is synthesized by means of a simple method, and a surprisingly synergetic effect of the Sc₂O₃-TiO₂ cocatalyst on the hydrogen storage performance of MgH₂ is observed. The MgH₂-Sc₂O₃/TiO₂@Gn composite starts to release hydrogen at 140 ℃ and reaches the peak dehydrogenation temperature at 239.9 ℃. It absorbs 6.55 wt% of H₂ in 1 min and desorbs 5.71 wt% of H₂ in 10 min at 300 ℃, showing excellent hydrogen absorption and desorption performance. Furthermore, with the decrease of the grain size and changes in the structure, the activity of the catalyst is greatly improved. The low-valent titanium and scandium and oxygen vacancies formed in the process of dehydrogenation facilitate hydrogen diffusion and electron transfer, and further improve the kinetic performance of the Mg/MgH₂-Sc₂O₃/TiO₂@Gn system. This study aims to provide insights into studying complex metal oxides as catalysts to improve hydrogen storage performance, and shed light on other catalysis-related research.