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, FeCoS@C derivative from ZIF-67, by utilizing the in situ formed C dispersive multiphase Mg2Co, alpha-Fe, Co3Fe7, and MgS to implement catalysis to MgH2. Noteworthily, MgH2-FeCoS@C rapidly ab-sorbs 6.78 wt% H 2 within 60 s at 573 K and can also absorb 4.56 wt% H 2 in 900 s at 473 K. Besides, the addition of FeCoS@C 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, alpha-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-FeCoS@C 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.(c) 2022 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

In this study, a carbon-supported transition metal compound, FeCoS@C derivative, was synthesized as a heterogeneous catalyst for MgH2. The results showed that the catalyst significantly improved the hydrogen storage performance of MgH2 by increasing the hydrogen absorption rate and reducing the dehydrogenation temperature. The transition metals and MgS played important roles in accelerating hydrogen transfer and providing stable catalytic effect. Additionally, the carbon skeleton provided more active sites for the catalysts, further enhancing the catalytic performance.