论文总字数：20549字

摘 要

水解制氢由于其效率高、反应条件温和和对环境友好，已被学者们广泛关注。镁在地球中储量丰富,价格低廉。且镁基材料易储存、反应条件温和、副产物为对环境友好的Mg(OH)₂，因而MgH₂是制备制高性价比氢气的理想选择。在MgH₂水解反应的初始阶段，水解速度正常，但是随着反应的进行，未反应的颗粒表面被反应中生成的Mg(OH)₂沉淀形成的钝化层包覆，阻碍了水向颗粒内部的扩散，降低了反应速率。要解决此问题便需要对MgH₂进行改性，目前较为传统的改性方式有：改变水溶液成分、添加催化剂、球磨等。这些方法可以有效的改善MgH₂的水解性能但同时也面临挑战：在球磨过程中材料会发生的冷焊和纳米颗粒的聚集，从而阻碍晶体和颗粒的进一步细化；仅仅提高水解反应速率却难以对速率进行调控。对比我们便提出使用对MgH₂进行聚合物包覆采取纳米限域的方式进行改性。

本文旨在探究使用不同的聚合物包覆方式（喷雾造粒法、离心成膜法）对MgH₂水解材料进行包覆对其水解性能的影响，以及使用不同长链聚合物，主要为PVP（聚乙烯吡咯烷酮）、PMMA（聚甲基丙烯酸甲酯）、PI（聚酰亚胺）、PAN（聚苯胺）对MgH₂进行包覆采取纳米限域的方式进行改性的实际效果。通过对镁基储氢材料的近似实验的结果进行分析类比，初步猜测不同的包覆方式以及不同的包覆聚合物对所制备的复合材料的水解性能均会产生影响。通过对已有实验数据的分析发现使用PAN对MgH₂进行喷雾造粒法包覆在对其水解速率的调控中起抑制作用。

关键词：MgH₂，水解制氢，聚合物，纳米限域

Controlling Hydrogen Production Rate by Hydrolysis of MgH₂ Coated by Different Polymers

Abstract

Hydrogen production has been widely concerned by scholars because of its high efficiency, mild reaction conditions and environmental friendliness. Magnesium has abundant reserves and low prices in the earth. Moreover, magnesium-based materials are easy to store, the reaction conditions are mild, and the by-products are environmentally friendly Mg(OH)₂. Therefore, MgH₂ is an ideal choice for preparing cost-effective hydrogen raw materials. In the initial stage of the MgH₂ hydrolysis reaction, the hydrolysis rate is normal, but as the reaction progresses, the surface of the unreacted particles is coated with the passivation layer formed by the Mg(OH)₂ precipitate formed in the reaction, which prevents water from flowing into the particles. Diffusion reduces the reaction rate.To solve this problem, MgH₂ needs to be modified. Currently, the more traditional modification methods are: changing the composition of the aqueous solution, adding a catalyst, and ball milling. These methods can effectively improve the hydrolysis performance of MgH₂ but also face challenges: cold welding of materials and aggregation of nanoparticles during the ball milling process, which hinders the further refinement of crystals and particles; it is difficult to improve the hydrolysis reaction rate. The rate is regulated. In comparison, we propose to use MgH₂ to coat the polymer with nano-domain modification.

The purpose of this article is to explore the effect of using different polymer coating methods (spray granulation method, centrifugal film formation method) to coat MgH₂ hydrolyzed materials on their hydrolysis performance, and the use of different long-chain polymers, mainly PVP (polypolymer Vinylpyrrolidone), PMMA (polymethyl methacrylate),PI (polyimide), PAN (polyaniline) coating MgH₂ in the nano-limited way to modify the actual effect. By analyzing the results of the approximate experiment of the magnesium-based hydrogen storage material, it is preliminarily guessed that different coating methods and different coating polymers will have an effect on the hydrolysis performance of the prepared composite material. Through the analysis of the existing experimental data, it is found that the coating of MgH₂ by PAN spraying granulation method has an inhibitory effect on the regulation of its hydrolysis rate.

Key words: MgH₂; Hydrogen production by hydrolysis; Polymer; Nanometer confinement

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 前言 1

1.2 制氢方式 1

1.2.1 电解水制氢 1

1.2.2 生物质制氢 1

1.2.3 光解水制氢 1

1.3 水解制氢及其研究现状 2

1.3.1 镁基水解材料 2

1.3.2 镁基水解材料改性方法 2

1.4 聚合物包覆对镁基储氢材料性能的影响 3

1.5 问题的提出 4

第二章 实验部分 5

2.1 实验原料及设备 5

2.1.1 原料 5

2.1.2 实验设备 5

2.2 样品的制备方法 5

2.2.1 氢化燃烧合成 5

2.2.2 高能球磨 6

2.2.3 聚合物包覆方式 6

2.3 水解性能测试 7

2.4 分析与表征 8

2.4.1 X射线衍射（XRD） 8

2.4.2 傅立叶变换红外光谱分析（FT-IR） 8

2.4.3 扫描电子显微镜 8

2.4.4 动力学分析 8

第三章 结果与讨论 10

3.1 聚合物包覆方式的选择 10

3.2 包覆聚合物的选择 12

3.3 PAN包覆对MgH₂水解制氢性能的影响 14

第四章 结果与展望 17

参考文献 18

致 谢 20

1. 绪论

前言

随着石油和煤炭等化石燃料资源的日渐枯竭以及人们对全球变暖等环境问题的日益重视，新兴的高效清洁能源的开发和利用被研究者们广泛关注。众多清洁能源中，氢能源有着其无可取代的优势：(1)氢具有142 MJ kg^-1的高能量密度，是一种有前途的能量载体^[1]。(2)氢的燃烧产物是水，不会产生污染且储备丰富，可持续发展。(3)氢燃烧性能好，燃烧迅速，与空气混合有较广的可燃范围。(4)氢能具有多种多样的利用形式，直接燃烧或者用于制作燃料电池。要实现氢能源的有效利用主要包括氢能的制取、储存、利用三个部分。制氢的过程是整个环节的基础，因而被广泛关注。

1.2 制氢方式

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