论文总字数：24327字

摘 要

Mg由于其价格低廉，且水解可在常温常压下进行，因此作为水解制氢材料极具潜力。Mg水解的理论制氢量为933 mL g^-1 (不含水的质量)，但是其水解过程中会产生Mg(OH)₂钝化层包覆在反应物表面，阻碍了水解的进行。对此已有诸如球磨和引入添加剂等改性方法，但目前报道的大多数添加剂本身不制氢，降低了体系的理论制氢量。本课题设计了一种Mg-Mg₂NiH₄体系，证明在不显著降低体系理论制氢量的同时显著提升制氢速率的可行性。

本课题通过氢化燃烧合成法 (HCS) 及机械球磨法复合制备了Mg-Mg₂NiH₄水解体系，并研究其在3.5 wt.% NaCl溶液中的水解制氢性能。实验结果表明，添加Ni后Mg的水解速率和产率得到了明显提升，加入Mg₂NiH₄后水解性能进一步提升，达到了832.8 mL g^-1。水解性能的提升归因于Mg₂NiH₄水解原位生成的Ni与Mg产生微原电池加速Mg的电化学腐蚀，并且Mg₂NiH₄水解也贡献了制氢量。本文还研究了球磨不同时间对水解性能的影响。球磨3 h的制氢量最大，为845.1 mL g^-1，球磨5 h达到最大制氢速率7214 mL g^-1min^-1。最后研究了不同温度下的水解，并结合水解曲线和Arrhenius方程计算得出球磨1 h的Mg-Mg₂NiH₄水解活化能为19.8 kJ mol^-1，进一步证明该体系具有优异的水解性能。

关键词：氢化燃烧合成 镁基材料 水解制氢 机械球磨

Study on Hydrolysis Performance of Mg-Mg₂NiH₄ System Catalyzed by In-situ Ni Formation

ABSTRACT

Mg, which is inexpensive and can be hydrolyzed at normal temperature and pressure, has considerable potential as a raw material for hydrogen production by hydrolysis. The theoretical hydrogen production for Mg hydrolysis is 933 mL g^-1 (mass without water), but the Mg(OH)₂ passivation layer is coated on the surface of the reactants during the hydrolysis process, preventing further hydrolysis. There were corrections such as ball milling and introduction of additives, but the additive itself does not produce hydrogen, which reduces the theoretical hydrogen production of the system. This project designed the Mg-Mg₂NiH₄ system, which can significantly improve the hydrogen production rate without significantly reducing the theoretical hydrogen production of the system.

In this project, the Mg-Mg₂NiH₄ hydrolysis system was synthesized by hydro-combustion synthesis (HCS) and mechanical ball mill, and the hydrolysis performance in 3.5 wt.% NaCl solution was investigated. After adding Ni, the hydrolysis rate and yield of Mg were significantly improved, and after adding Mg₂NiH₄, the hydrolysis performance was further improved, reaching 832.8 mL g^-1. The improved hydrolytic performance is due to the fact that Ni and Mg produce micro-primary cells to accelerate the electrochemical corrosion of Mg, and the hydrolysis of Mg₂NiH₄ also contributes to the amount of hydrogen produced. This article also studies the effect of ball milling on hydrolysis performance at various times. The maximum amount of hydrogen produced by ball milling in 3 hours was 845.1 mL g^-1 while the maximum hydrogen production rate in ball milling in 5 hours reached 7214 mL g^-1 min^-1. Finally, the hydrolysis at different temperatures was studied, and the hydrolysis activation energy of the ball milled Mg-Mg₂NiH₄ for 1 h was calculated to be 19.8 kJ mol^-1 by combining the hydrolysis curve and Arrhenius equation, which further proved that the system had excellent hydrolysis performance.

KEY WORDS: Hydrogen combustion synthesis; Magnesium-based materials; hydrolysis to produce hydrogen; mechanical ball milling

目 录

摘 要 I

ABSTRACT II

第一章 绪论 1

1.1引言 1

1.2制氢方式研究现状 2

1.2.1天然气重整 2

1.2.2生物质制氢 2

1.2.3电解水制氢 3

1.2.4太阳能制氢 3

1.3水解制氢研究现状 4

1.3.1金属氢化物水解制氢 4

1.3.2金属水解制氢 5

1.4问题的提出与本文的研究内容 7

第二章 实验方法 9

2.1实验原料 9

2.2样品的制备 9

2.2.1氢化燃烧合成制备Mg₂NiH₄ 9

2.2.2球磨处理 10

2.3水解性能测试 11

2.4结构性能分析 12

2.4.1 XRD分析 12

2.4.2 XPS分析 12

2.4.3 SEM测试 12

2.5动力学机理分析 13

第三章 Mg₂NiH₄促进Mg水解制氢 14

3.1 HCS制备Mg₂NiH₄的表征 14

3.2不同添加剂对Mg水解性能的影响 14

3.3球磨时间对Mg-Mg₂NiH₄水解性能的影响 19

3.4温度对Mg-Mg₂NiH₄水解性能的影响 21

3.5本章小结 23

四 结论与展望 24

4.1结论 24

4.2展望 25

参考文献 26

致谢 29

第一章 绪论

1.1引言

能源是人类社会生产生活的必需，是国民经济发展的重要基础。化石能源如煤炭，石油等日益枯竭，同时也带来了诸多环节污染问题。因此寻找更加清洁高效以及可持续发展的新能源成为世界性的课题。

与传统化石燃料相比，首先氢储量丰富，可通过太阳能、风能等一次能源制取。第二，氢的燃烧能量密度高，1 kg的氢气标况下完全燃烧释放出142.9 MJ的热量，是汽油的三倍。第三，燃烧产物只有水，不会产生其他排放^[1]。因此氢能是一种被寄予厚望的理想二次能源。许多发达国家都十分重视氢能的开发，例如日本的“日光计划”等。我国也于2006年开展“973计划”和“863计划”等项目进行氢能源等开发和研究。

请支付后下载全文，论文总字数：24327字