The effect of K2SiF6 on the MgH2 hydrogen storage properties

• 作者: M.Ismail M.S.Yahya N.A.Sazelee N.A.Ali F.A.Halim Yap N.S.Mustafa
• 来源期刊: 镁合金学报(英文)
• 学科: 工学
• 关键词: Catalytic effect Magnesium hydride Hydrogen storage Sorption properties Contracting volume model
• 年，卷（期）: 2020,（3）
• 页码范围: 832-840
• 页数: 9页
• 分类号: TG1

摘要

The catalytic effect of K2SiF6 on MgH2 was first timely studied.The MgH2+5 wt.%K2SiF6 was prepared via the ball milling technique.The catalyst had lessened the initial decomposition temperature by 134℃ and 48℃ as compared to both pristine and milled MgH2 samples,respectively.In 2 minutes,4.5 wt.%of hydrogen was absorbed(250℃)by the doped composite,which was 0.8 wt.%higher than the milled MgH2.Meanwhile,for the desorption kinetics(320℃,1 atm),the amount of desorbed hydrogen was increased by 2.4 wt.%and 2.3 wt.%for the first 10 and 20 minutes.Besides,contracting volume and Johnson-Mehl-Avrami models were used to analyse the kinetics sorptions.The decomposition activation energy calculated based on Kissinger equation was 114 kJ/mol.As for the active species,Mg2Si,MgF2 and KH were formed during the heating process.These active species are speculated to be responsible for the improvement of the hydrogenation properties of the composite.