International Journal of Hydrogen Energy, Vol.44, No.26, 13561-13568, 2019
Improvement of hydrogen storage properties of Mg by catalytic effect of Al-containing phases in Mg-Al-Ti-Zr-C powders
The hydrogen storage (HS) properties and structures of ball-milled (BM) Mg-Ti-Al-Zr-C powders prepared under various milling conditions were investigated. The additions Ti, Zr, Al and C improved HS performance of Mg-based materials. The beneficial effect can be explained by catalysis of particles rich in Al, Ti and Zr located on the surface of Mg grains. The particles provide effective pathways for the hydrogen diffusion from/into the re/forming MgH2. The morphological and microstructural characteristics were investigated by scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and by X-ray diffraction (XRD). The hydrogen sorption was measured by Sieverts method. The various preparation processes of powders resulted in two phases: Mg17Al12, Mg1.95Al0.05. It was found, that mainly these phases had a strong positive effect on HS properties of studied powders. Both phases increased desorption/absorption equilibrium pressure. Improvement of desorption kinetics of powder containing phase Mg17Al12 was more expressive than powders with of Mg1.95Al0.05. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.