Boosting the hydrogen storage performance of magnesium hydride with metal organic framework-derived Cobalt@Nickel oxide bimetallic catalyst

In this study, a MOF-derived bimetallic [email protected] catalyst was synthesized and doped into MgH2 to improve the hydrogen desorption and resorption kinetics. The [email protected] catalyst decreased the onset dehydrogenation temperature of MgH2 by 160 °C, compared with un-doped MgH2. The MgH2 + 9% (mass) [email protected] composite released 6.6% (mass) hydrogen in 350 s at 315 °C and uptook 5.4% (mass) hydrogen in 500 s at 165 °C, showing greatly accelerated de/rehydrogenation rates. Besides, the desorption activation energy of MgH2 + 9% (mass) [email protected] was decreased to (93.8 ± 8.4) kJ·mol−1. Noteworthy, symbiotic Mg2NiH4/Mg2CoH5 clusters were in-situ formed from bimetallic precursors and inlaid on MgH2 surface, which are considered as “multi-step hydrogen pumps”, and provides surface pathways for hydrogen absorption. Meanwhile, the introduced Mg2NiH4/Mg2CoH5 interfaces could provide numerous low energy barrier H diffusion channels, therefore accelerating the hydrogen release and uptake. This research proposes new insights to design high-efficiency bimetallic catalyst for MgH2 hydrogen storage.