Promoted de/rehydrogenation kinetics in MgH2 through catalytic doping with a mixed cerium-niobium oxide

In this study, a mixed cerium-niobium oxide, CeNbO x , was successfully synthesized and combined with MgH 2 through high-energy ball milling to enhance its hydrogen storage performance. The addition of 10 wt% CeNbO x significantly reduced the beginning dehydrogenation temperature of MgH 2 to 209.7 °C, representing a substantial decrease of 87.9 °C compared to the ball-milled counterpart without the additive. At 100 °C, the CeNbO x -doped composite absorbed 5.2 wt% of H 2 within 5 min, and at 300 °C, it released 6.3 wt% of H 2 in 10 min. Various characterization techniques, such as TEM and XPS, revealed the in-situ formation of lower valence CeH 2.53 and Nb-based active species (Nb, NbO 2 , and NbH 2 ) derived from CeNbO x during the dehydrogenation/hydrogenation process. These compounds can act as reactive sites that efficiently facilitate the adsorption and dissociation of H 2 molecules in MgH 2 . This study offers a valuable strategy for catalyst design aimed at developing high-performance composites for hydrogen storage.