Synthesis and hydrogen desorption kinetics of Mg2FeH6- and Mg2CoH5-based composites with in situ formed YH3 and Mg2NiH4 nanoparticles.

Mg₂FeH₆- and Mg₂CoH₅-based composites with in situ formed YH₃ and Mg₂NiH₄ nanoparticles were synthesized by ball milling of Mg₁₀YNi + 4Fe (in mole ratio) and Mg₁₀YNi + 4Co powders, respectively, at 4 MPa H₂ followed by hydrogenation at 673 K for 60 h under a hydrogen pressure of 7 MPa. It is found that the nanocrystalline YH₃ and Mg₂NiH₄ particles are indeed embedded in Mg₂FeH₆ and Mg₂CoH₅ matrixes. The hydrogen desorption rates of Mg₂FeH₆- and Mg₂CoH₅-based composites are enhanced compared to those undoped Mg₂FeH₆ and Mg₂CoH₅ hydrides, respectively, due to the synergetic catalysis of nanosized YH₃ and Mg₂NiH₄ particles. This finding provides us with an efficient and simple approach for the improvement in hydrogen desorption kinetics of Mg-based hydrogen storage materials. [ABSTRACT FROM AUTHOR]