交联型金属氧化物气凝胶在催化体系的应用研究

论文总字数：18995字

摘 要

利用电催化CO₂还原技术，将CO₂在常温常压下转化为具有附加价值的燃料或化工产品（醇类、烃类等），可以用来应对燃烧化石燃料带来的“温室效应”和能源危机。然而，目前CO₂电催化还原技术还不能投入生产活动，将实验室中高标准、高要求的CO₂电催化还原技术投入生产线，仍然需要降低成本要求。例如CO₂的水溶性差，电催化还原系统动力学过程缓慢，催化剂过电位高，使用寿命短等问题。因此，制备一种活性高、选择性高、稳定性好的纳米催化剂仍是十分必要的。

本文通过对水热反应的反应温度、反应时间和酸碱环境的有效调控，将超微小的SnO₂纳米晶体沉积在石墨烯上，研制了一种具有三维网格结构的纳米SnO₂催化剂。同时采用X射线衍射(XRD)以及扫描电镜((SEM)对SnO₂纳米催化剂的组分和微观结构进行了检测，并采用循环伏安法（CV）、线性扫描伏安法和恒电位电解I-T曲线对CO₂电催化还原性能进行了分析。采用液相色散定量分析CO₂的还原产物——甲酸和氢气，采用法拉第效率公式计算电流效率。讨论了不同制备条件和催化剂形态对二氧化碳还原选择性和电流效率的影响机制。对比研究表明，这类电催化剂的电催化活性依赖于石墨烯上SnO₂的负载。

关键词：CO₂电催化还原，交联型氧化物，法拉第效率

ABSTRACT

The electroreduction of carbon dioxide (CO₂) into fuels and other chemicals can be used to cope with the "greenhouse effect" and energy crisis caused by burning fossil fuels. However, at present, the electroreduction of carbon dioxide cannot be put into production activities. To put it into the production line still needs to reduce the cost requirements. For example, the water solubility of CO₂ is poor, the kinetic process of electrocatalytic reduction system is slow, the catalyst overpotential is high, and the service life is short. Therefore, it is necessary to prepare a nano-catalyst with high activity, high selectivity and good stability.

In my work, an nano-SnO₂ catalyst with three-dimensional grid structure was developed by depositing ultra-small SnO₂ nanocrystals on graphene through effective regulation of hydrothermal reaction temperature, reaction time and acid-base environment.

The components and microstructure of SnO₂ nano-catalyst were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the CO₂ electrocatalytic reduction performance was analyzed by cyclic voltammetry (CV) scanning and I-T curve. The reduction product of CO₂ - formic acid was quantitatively analyzed by ion chromatography (IC). And we discussed the effects of different preparation conditions and catalyst morphology on carbon dioxide reduction selectivity and current efficiency.

Compared with other studies, we found that the electrocatalytic activity of such electrocatalysts depends on the loading of SnO₂ on graphene.

Keywords: The electroreduction of carbon dioxide, Crosslinked oxides, Faraday efficiency

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1 引言 1

1.2 CO₂的捕获和封存 1

1.3 CO₂的转化 1

1.3.1 CO₂光催化还原 2

1.3.2 CO₂电催化还原 3

1.4 CO₂电催化还原阴极催化剂 3

1.4.1 金属单质 5

1.4.2 金属合金 6

1.4.3 掺杂材料 6

1.4.4 金属氧化物复合材料 7

1.5 课题意义和研究内容 7

第二章 实验试剂和仪器设备和研究方法 9

2.1 实验试剂 9

2.1.1 所用试剂 9

2.1.2 主要试剂简介 9

2.2 仪器设备 10

2.2.3 所需仪器 10

2.2.4 仪器简介 10

2.3 研究方法 11

2.3.1 锡基交联型氧化物催化剂的制备 11

2.3.2 阴极电极的制备 12

2.3.3 催化剂电化学性能测试 12

第三章 结果与讨论 14

3.1 锡基交联型氧化物催化剂的物理表征 14

3.1.1 X射线衍射（XRD）结构表征 14

3.1.2 扫描电子显微镜（SEM）形貌分析 14

3.2 锡基交联型氧化物催化剂的电化学性能 16

3.2.1 循环伏安测试 17

3.2.2 线性扫描伏安测试 18

3.2.3 恒电位电解I-T曲线分析 19

3.2.4 法拉第效率分析 20

总结 21

参考文献 22

致 谢 23

1. 绪论

1.1引言

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