Synthesis and hydrogen desorption kinetics of Mg_(2)FeH_(6)-and Mg_(2)CoH_(5)-based composites with in situ formed YH_(3)and Mg_(2)NiH_4 nanoparticles

摘要

Mg_(2)FeH_(6)-and Mg_(2)CoH_(5)-based composites with in situ formed YH_(3)and Mg_(2)NiH_4 nanoparticles were synthesized by ball milling of Mg_(10)YNi+4Fe(in mole ratio)and Mg_(10)YNi+4Co powders,respectively,at4 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 YH_(3)and Mg_(2)NiH_4 particles are indeed embedded in Mg_(2)FeH_(6)and Mg_(2)CoH_(5)matrixes.The hydrogen desorption rates of Mg_(2)FeH_(6)-and Mg_(2)CoH_(5)-based composites are enhanced compared to those undoped Mg_(2)FeH_(6)and Mg_(2)CoH_(5)hydrides,respectively,due to the synergetic catalysis of nanosized YH_(3)and Mg_(2)NiH_4 particles.This finding provides us with an efficient and simple approach for the improvement in hydrogen desorption kinetics of Mg-based hydrogen storage materials.