Improved Hydrogen Absorption/Desorption Properties of MgH₂ by Co–Catalyzing of YH₂ and Co@C

Hydrogen absorption and desorption kinetics properties of MgH₂ were improved by co-doping of commercial YH₂ and a synthesized Carbon supported nano-Co (Co@C) catalyst, which was prepared by calcination of Zeolitic Imidazolate Framework-67 (ZIF-67) precursor. YH₂ addition shows great enhancement on the hydrogen absorption kinetics. The ball-milled MgH₂-YH₂ absorbs 6.5 wt.% of hydrogen within 100 s at 300 °C. The Co@C catalyst greatly enhances the absorption and desorption kinetics, while the absorption kinetics is slightly slower than that of MgH₂-YH₂ at 250 °C and 275 °C. MgH₂-YH₂-Co@C exhibited prominent absorption and desorption kinetics, reaching full hydrogenation within 150 s at 250 °C and releasing 6 wt.% hydrogen within 1700 s at 300 °C. After hydrogenation and dehydrogenation, particle size of YH₃ remains ∼500 nm, and the fine Co@C particles distributed homogeneously in the MgH₂ matrix.