论文总字数：29874字

摘 要

镁基储氢材料被认为是最具有潜力的储储氢材料之一。但是其动力学和热力学性能较差，制约了其实际应用。本文综合纳米化和催化两种工艺的优势，加入纳米级TiC并采用氢化燃烧合成 机械球磨（HCS MM）法制备Mg₉₅Ni₅-TiC纳米镁基复合储氢合金材料。实验分别利用了X射线衍射（XRD）对样品成分及晶粒尺寸进行分析，扫描电子显微镜（SEM）和透射电子显微镜（TEM）对微观形貌及颗粒尺寸进行表征，差示扫描量热仪（DSC）和压力-组成-温度测试仪（PCT）测试样品的储氢性能。

实验结果表明，加入5 wt.%TiC后经HCS MM，产物中MgH₂晶粒尺寸下降至24.8 nm，平均颗粒尺寸由未加TiC的460 nm下降至350 nm；DSC结果显示TiC添加量越多，相同条件下材料脱氢温度越低，体现TiC良好的助磨性和催化性。Mg₉₅Ni₅-TiC复合储氢材料在300 ℃下，1 h内吸氢量为5.1 wt.%，脱氢量为5 wt.%，且在275 ℃下经过5次吸放氢循环后，吸放氢速率和吸氢容量未发生明显衰退，储氢容量仍达5.3 wt.%，体现出良好的循环稳定性。

关键词：镁镍复合储氢材料 TiC 氢化燃烧合成 机械球磨

Preparation and hydrogen storage mechanism of high stability Mg₉₅Ni₅-TiC nanocomposite materials

Abstract

Magnesium hydrogen storage material is considered as one of the most potential hydrogen storage materials, its poor dynamic and thermodynamic properties restrict its practical application.In this paper, combining the advantages of nano-chemical and catalytic processes, nano-TiC composite hydrogen storage material Mg₉₅Ni₅-TiC was prepared by Hydrogenation combustion synthesis and mechanical milling (HCS MM) method.Experiments respectively using X-ray diffraction (XRD) was carried out on the sample composition and grain size analysis, scanning electron microscope (SEM) and transmission electron microscope (TEM) on the microstructure and particle size were characterized, differential scanning calorimeter (DSC) and pressure-composition-temperature tester (PCT) on the hydrogen storage properties of the samples.

The experimental results showed that adding 5 wt.%TiC during HCS MM process, the grain size of MgH₂ in the product decreased to 24.8 nm, and the average particle size was decreased from 460 nm without TiC to 350 nm. DSC results showed that the more TiC added, the lower the dehydrogenation temperature was achieved under the same conditions, indicating the good grinding and catalytic properties of TiC. The hydrogen absorption and desorption capacity of Mg₉₅Ni₅-TiC nanocomposite were about 5.1 wt.% and 5 wt.% within 1 h at 300 ℃, respectively. After 5 times of de-/hydriding cycles at 275 ℃, the hydrogen storage capacity did not decline significantly, and the hydrogen storage capacity was still up to 5.3 wt.%, showing good cyclic stability.

Key Words：Magnesium-nickel composite hydrogen storage material;TiC;Hydrogenation combustion synthesis; mechanical mill

目 录

摘 要 I

Abstract II

第一章 文献综述 1

1.1 引言 1

1.2 镁基储氢材料改性的研究进展 1

1.2.1 合金化 1

1.2.2 纳米化及纳米限域 2

1.2.3 添加催化剂 3

1.3 镁基复合储氢材料概述 4

1.3.1 镁基材料与单质的复合 4

1.3.2 镁基材料与化合物复合 5

1.4 氢化燃烧合成法及机械球磨 5

1.4.1 氢化燃烧合成法 6

1.4.2 机械球磨法 6

1.5 本课题的研究思路和主要工作 7

第二章 实验部分 8

2.1 实验原料及设备 8

2.1.1 原料 8

2.1.2 实验设备 8

2.2实验方法及Mg₉₅Ni₅-TiC复合储氢材料的制备 8

2.2.1 氢化燃烧合成法制备Mg₉₅Ni₅-TiC复合储氢材料 8

2.2.2 氢化燃烧及机械球磨制备Mg₉₅Ni₅-TiC复合储氢材料 9

2.3氢化燃烧及机械球磨制备Mg₉₅Ni₅-TiC复合储氢材料的吸放氢性能测试 9

2.4 微观结构表征 11

2.4.1 X射线衍射分析（XRD） 11

2.4.2 透射电子显微分析（TEM） 11

2.4.3 PCT测试 11

2.4.4 扫描电子显微镜/能谱分析（SEM/EDS） 11

2.4.5 热重-差示扫描热分析（TG-DSC） 11

第三章 结果与讨论 13

3.1 Mg₉₅Ni₅-TiC复合储氢材料相成分 13

3.2 样品微观结构表征 16

3.3 样品储氢性能测试 18

第四章 结论与展望 23

4.1 结论 23

4.1 展望 23

参考文献 25

致 谢 28

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