Contamination Effects on Improving the Hydrogenation/Dehydrogenation Kinetics of Binary Magnesium Hydride/Titanium Carbide Systems Prepared by Reactive Ball Milling.

摘要: Ultrafine MgH2 nanocrystalline powders were prepared by reactive ball milling of elemental Mg after 200 h high-energy under a hydrogen gas pressure 50 bar. The as-prepared metal hydride contaminated with 2.2 wt. % FeCr-stainless steel that was introduced to the upon using stainless tools made same alloy. as-synthesized doped previously TiC nanopowders, which 2.4 FeCr (materials media), and then milled atmosphere for h. results related morphological examinations fabricated nanocomposite beyond micro-and nano-levels showed excellent distributions 5.2 TiC/4.6 dispersoids embedded into fine host matrix powders. as-fabricated MgH2/5.2 possessed superior hydrogenation/dehydrogenation characteristics, suggested low value activation energy (97.74 kJ/mol), short time required achieving complete absorption (6.6 min) desorption (8.4 5.51 H2 at moderate temperature 275 °C ranging from 100 mbar 8 van’t Hoff approach used calculate enthalpy (DH) entropy (DS) hydrogenation MgH2, found be -72.74 kJ/mol 112.79 J/mol H2/K, respectively. Moreover, method employed DH DS dehydrogenation, 76.76 119.15 This new system absorption/desorption cyclability 696 cycles, achieved in cyclic-life-time 682