Graphene-Supported Sc_(2)O_(3)/TiO_(2) for Superior Catalysis on Hydrogen Sorption Kinetics of MgH_(2)

Complex metal oxide catalysts greatly accelerate the hydrogen sorption rates in the magnesium hydride system.In this study,the graphene-supported Sc_(2)O_(3)/TiO_(2) catalyst is synthesized by means of a simple method,and a surprisingly synergetic effect of the Sc_(2)O_(3)-TiO_(2) cocatalyst on the hydrogen storage performance of MgH_(2) is observed.The MgH_(2)-Sc_(2)O_(3)/TiO_(2)@Gn composite starts to release hydrogen at 140°C and reaches the peak dehydrogenation temperature at 239.9°C.It absorbs 6.55 wt%of H_(2) in 1 min and desorbs 5.71 wt%of H_(2) in 10 min at 300°C,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/MgH_(2)-Sc_(2)O_(3)/TiO_(2)@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.