排序方式: 共有112条查询结果,搜索用时 31 毫秒
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利用PCT测试仪和X射线衍射及场发射扫描电镜等测试手段对NaAlH4 2%(摩尔分数)M(M=Ni、LaCl3、Ce(SO4)2)的吸放氢性能和微观结构进行了研究.结果表明,催化剂的掺杂均可降低NaAlH4的放氢温度,催化剂的催化效果依次为:Ce(SO4)2>LaCl3>Ni.掺杂稀土化合物可改善NaAlH4的吸氢性能,使第一步吸氢反应:3NaH Al (3)/(2)H2Na3AlH6完全发生,特别是Ce(SO4)2的掺杂,使样品发生了部分(1)/(3)Na3AlH6 (2)/(3)Al H2NaAlH4的第二步吸氢反应,吸氢量达到2.808%(质量分数).掺杂Ce(SO4)2有利于NaAlH4 在球磨过程中颗粒尺寸细化,颗粒的细化增强了NaAlH4的活性,导致其吸放氢性能提高. 相似文献
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The Mg2Ni-type alloys with nominal compositions of Mg20Ni10-xCox(x=0,1,2,3,4,%,mass fraction) were prepared by melt-spinning technology.The structures of the alloys were studied by XRD,SEM and HRTEM.The hydrogen absorption/desorption kinetics and the electrochemical performances of the alloys were measured.The results show that no amorphous phase forms in the as-spun Co-free alloy,but the as-spun alloys containing Co show a certain amount of amorphous phase.The hydrogen absorption capacities of the as-cast ... 相似文献
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In order to improve the hydrogenation and dehydrogenation performances of the Mg2Ni-type alloys, Mg was partially substituted by La in the alloy, and melt spinning technology was used for the preparation of the Mg20-xLaxNi10 (x=0, 2, 4, 6) hydrogen storage alloys. The structures of the alloys were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). It was found that no amorphous phase formed in the as-spun La-free alloy, but the as-spun alloys containing La held a major amorphous phase. When La content x≤2, the major phase in the as-cast alloys was Mg2Ni phase, but with further increase of La content, the major phase of the as-cast alloys changed into LaNi5+LaMg3 phase. Thermal stability of the as-spun alloys was studied by differential scanning calorimetry (DSC), showing that spinning rate was a negligible factor on the crystallization temperature of the amor-phous phase. The hydrogen absorption and desorption kinetics of the as-cast and as-spun alloys were measured using an automatically con-trolled Sieverts apparatus, confirming that the hydrogen absorption and desorption capacities and kinetics of the as-cast alloys clearly in-creased with rising La content. For La content x=2, the as-spun alloy displayed optimal hydrogen desorption kinetics at 200 ℃. 相似文献
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用快淬工艺制备了Mg2Ni型合金,其名义成分为Mg2Ni1-xCox(x=0,0.1,0.2,0.3,0.4)。以XRD、SEM、TEM分析了铸态及快淬合金的结构。用程控模拟电池测试仪测试了合金的电化学贮氢动力学。用电位跃迁法计算了氢在合金中的扩散系数。用电化学工作站测试了合金的电化学交流阻抗谱(EIS)和Tafel极化曲线。结果表明,快淬态无Co合金具有典型的纳米晶结构,而Co含量为0.4的快淬态合金具有纳米晶/非晶结构,表明Co替代Ni可以提高Mg2Ni型合金的非晶形成能力,且快淬态合金的非晶化程度随Co替代量的增加而增加。Co替代Ni显著地提高了合金电化学贮氢动力学。当Co含量从0增加到0.4时,淬速为25m/s的快淬态合金的高倍率放电能力(HRD)从65.3%增加到75.3%,氢扩撒系数(D)从2.22cm2/s增加到3.34cm2/s,极限电流密度(IL)从247.8mA/g增加到712.4mA/g。 相似文献
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