A novel Ce 0.8 Fe 0.1 Zr 0.1 O 2 solid solution with high catalytic activity for hydrogen storage in MgH 2 .

The effect of the solid solution Ce 0.8 Fe 0.1 Zr 0.1 O 2 , successfully prepared by a hydrothermal synthesis method, on the hydrogen sorption properties of MgH 2 is systemically investigated. The Ce 0.8 Fe 0.1 Zr 0.1 O 2 -modified MgH 2 composite exhibits remarkable hydrogen kinetics properties and thermodynamics behavior compared to those of as-milled MgH 2 , with a reduction in the initial desorption temperature of approximately 82 K. With respect to the hydrogen kinetics, the Ce 0.8 Fe 0.1 Zr 0.1 O 2 -added sample could uptake approximately 5.3 wt% H 2 at 473 K in 2500 s, whereas only 1.5 wt% hydrogen could be absorbed by pristine MgH 2 in the same conditions. Furthermore, about 4.5 wt% of hydrogen could be desorbed by Ce 0.8 Fe 0.1 Zr 0.1 O 2 -doped MgH 2 composite at 623 K, which was 2 wt% higher than the as-milled MgH 2 sample over the same period of time. The decomposition apparent activation energy for MgH 2 -Ce 0.8 Fe 0.1 Zr 0.1 O 2 is reduced to 84.3 kJ mol -1 , which is about 77 kJ mol -1 lower than that of pristine MgH 2 . It is believed that the notable improvement in the hydrogen sorption kinetics is due to the in situ -formed active species of CeH 2.51 and MgO as well as the abundant oxygen vacancies, which play a vital role in catalyzing the hydrogen sorption performance of MgH 2 .