Catalytic effect of MOF-derived transition metal catalyst FeCoS@C on hydrogen storage of magnesium

The introduction of the heterogeneous catalysts with high activity can significantly improve hydrogen storage performance of MgH2, therefore, in this paper, we synthesize a carbon-supported transition metal compound, [email protected] derivative from ZIF-67, by utilizing the in situ formed C dispersive multiphase Mg2Co, α-Fe, Co3Fe7, and MgS to implement catalysis to MgH2. Noteworthily, MgH2[email protected] rapidly absorbs 6.78 wt% H2 within 60 s at 573 K and can also absorb 4.56 wt% H2 in 900 s at 473 K. Besides, the addition of [email protected] results in decreasing of the initial dehydrogenation temperatures of MgH2 from 620 to 550 K. The dehydrogenation activation energy of MgH2 decreases from 160.7 to 91.9 kJ mol–1. Studies show that the Mg2Co, α-Fe, and Co3Fe7 act as “hydrogen channels” to accelerate hydrogen transfer due to the presence of transition metals, and MgS with excellent catalytic effect formed from MgH2[email protected] provides a strong and stable catalytic effect. Besides, the carbon skeleton obtained by the carbonization of ZIF-67 not only serves as a dispersion for the multiphase catalytic system, but also provides more active sites for the catalysts. Our study shows that the multiphase and multiscale catalytic system provides an effective strategy for improving the hydrogen storage performance of MgH2.