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 H-2 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.