Improvement in Hydrogention and Dehydrogenation Characteristics of Magnesium by Addition of Titanium (III) Chloride via Transformation-Accompanying Milling

Abstract

A specimen consisting of 90 wt.% Mg and 10 wt.% TiCl₃ (called 95 Mg + 10 TiCl₃) was made by transformation-accompanying milling, and its hydrogenation and dehydrogenation features were checked. The activation of 95 Mg + 10 TiCl₃ was not demanded. 95 Mg + 10 TiCl₃ revealed an useful hydrogenation-dehydrogenation capacity (the quantity of hydrogen absorbed in 60 min) of about 5.6 wt.%. At n = 1, the specimen absorbed 4.06 wt.% of hydrogen in 5 min, 5.09 wt.% of hydrogen in 10 min, and 5.59 wt.% of hydrogen in 60 min at 593 K in 1.2 MPa H₂. At n = 1, the specimen desorbed 0.47 wt.% of hydrogen in 2.5 min, 3.81 wt.% of hydrogen in 30 min, and 5.20 wt.% of hydrogen in 60 min at 593 K in 0.1 MPa H₂. The XRD pattern of 95 Mg + 10TiCl₃ dehydrogenated at the 4th hydrogenation-dehydrogenation cycle included Mg, β-MgH₂, MgO, and a small amount of TiH_1.924 phases. The P (equilibrium hydrogen pressure)-C (composition)-T (temperature) curve at 593 K revealed an equilibrium plateau pressure at about 0.25 MPa. 95 Mg + 10 TiCl₃ had a higher early hydrogenation rate and a larger amount of hydrogen absorbed in 60 min than Mg, 90 Mg + 10 Fe₂O₃, 90 Mg + 10 MnO, and 90 Mg + 10 TaF₅, the hydrogenation and dehydrogenation features of which were before informed of.

DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16375