Improvement of hydrogen-sorption characteristics of Mg by reactive mechanical grinding with prepared by spray conversion

Nano-structured Cr 2 O 3 powder could be produced by spray conversion (spray drying of an aqueous of Cr nitrate, oxidation and milling). mples Mg—10 wt% Cr 2 O 3 using nano-structured Cr 2 O 3 synthesized by spray conversion were prepared by mechanical grinding under H 2 (reactive mechanical grinding) under the optimum conditions, previously studied, for the preparation of the sample Mg—10 wt% Fe 2 O 3 using purchased Fe 2 O 3 . The sample Mg—10 wt% Cr 2 O 3 as milled absorbed 4.48 wt% H 2 at 593 K under 12 bar H 2 for 60 min. Its activation was accomplished after two hydriding–dehydriding cycles. The activated sample absorbed 5.48 wt% H 2 for 10 min and 5.93 wt% H 2 for 60 min at 593 K, 12 bar H 2 , and desorbed 3.65 wt% H 2 at 603 K, 1.0 bar H 2 for 60 min. H 2 -storage capacity was 6.38 wt% under 12 bar H 2 at 593 K (from P–C-T curve). Reactive mechanical grinding of Mg with Cr 2 O 3 by spray conversion increased the hydriding rate effectively but increased a little the dehydriding rate, compared with reactive mechanical grinding of Mg with Fe 2 O 3 purchased, Fe 2 O 3 by spray conversion, MnO and SiO 2 by spray conversion.