Preparation and Hydrogen Storage Properties of Mg-20 wt. Mg_2Ni_(0.8)Cr_(0.2) Composite with TiO_2 Nanoparticles

摘要

Mg and Mg-Ni-based hydrides were mechanically milled with TiO_2 nanoparticles to prepare Mg-20 wt.% Mg2Ni_(0.8)Cr_(0.2)-l.5 wt.% TiO_2 composite. XRD results showed that the hydrides decomposed partly during ball milling. Under the combined effects of the catalyst of TiO_2 nanoparticles, Mg_2Ni_(0.8)Cr_(0.2) alloy and Ni particles precipitated, and the mechanical driving force, the composite showed rapid hydrogen absorption/desorption kinetics. The absorption temperatures of the composite were greatly decreased and the rates of hydriding were increased. The composite can absorb 4.6 wt.% H at 373 K within 3 min and desorb 4.33 wt.% H at 573 K within 20 min.