论文总字数：23141字

摘 要

在气体传感器的组成部分中，敏感材料是最为重要的，它将直接影响传感器的性能。MoO₃是过渡金属氧化物，作为敏感材料，其因有丰富d轨道电子等特点而具有良好的性能，如选择性好、响应恢复速度快、响应值与浓度间有良好的线性关系等，应用潜力巨大。但对于某些特定气体（如甲醇和乙醇），其还是会无法完全区分，出现选择性不够的问题，因此需采取有效措施对其进行改性。本文选择MoO₃纳米带为研究对象，利用合成工艺参数改变和表面修饰手段优化性能。

MOFs材料由于其多孔结构中孔道尺寸规律、可调控，理论上可对相应体积大小的气体分子进行筛选，达到对特定气体的选择性。有文献报道：以合成条件最佳化的ZnO@ZIF-8为基础的纳米复合物传感器和原来的ZnO纳米线传感器相比，对C₇H₈ 和C₆H₆ 表现出可忽略的响应，而对H₂ 的响应较高，表现出了明显的选择性。此外，有报道显示其孔径变化后对气体具有物理筛选的功能，因此有望增强传统气敏材料的选择性。

故本文选择ZIF-70对MoO₃纳米带进行表面修饰，通过ZIF-70固有的孔径尺寸对被测气氛进行物理刷选，进而提高MoO₃纳米带对特定目标气体的选择性。本文利用水热法制备MoO₃纳米带，论文主要研究了通过控制水热时间来探究其生长机理；ZIF-70表面修饰前后MoO₃纳米带对甲醇和乙醇的响应变化。

研究结果表明：ZIF-70/MoO₃复合材料较未修饰的MoO₃纳米带而言，对甲醇（较乙醇而言）有更好的选择性。

本文的特色：将传统的过渡金属氧化物气敏材料与新兴的MOFs材料进行复合，利用MOFs材料的优点对传统材料进行改性。

关键词： MoO₃；MOF；气敏性能；物理筛选

Abstract

Among all of the components of the gas sensor, the sensitive material is the most important, which will directly affect the performance of the sensor. MoO₃ is a transition metal oxidation material, which has good performance due to its abundant d orbital electrons, such as good selectivity, fast response recovery speed, and good linear relationship between response value and concentration. It has great application potential. However, MoO₃ still cannot be completely distinguished certain gases from each other such as methanol and ethanol, resulting in the problem of insufficient selectivity. Therefore, effective measures should be taken to modify them. In this paper, MoO₃ nanoribbons were selected as the research object, and the synthesis process parameters were changed and the surface modification was used to optimize the performance.

Due to the regularity and regulation of pore size in the porous structure of MOFs material, the corresponding volume of gas molecules can be screened in theory to achieve the selectivity of specific gas.It has been reported in the literature that compared with the original ZnO nanowire sensor, the ZnO @ZIF-8 based nanometer composite sensor under the optimal synthesis condition shows negligible response to C₇H₈ and C₆H₆, while the response to H₂ is higher, showing obvious selectivity.In addition, it has been reported that the gas can be physically screened after the pore size changes, so it is expected to enhance the selectivity of traditional gas-sensitive materials.

Therefore, ZIF-70 was selected to modify the surface of MoO₃ nanoribbon in this paper, and the measured atmosphere was physically brushed through the inherent aperture of ZIF-70, so as to improve the selectivity of MoO₃ nanoribbon to specific target gases.In this paper, MoO₃ nanoribbon was prepared by hydrothermal method. The growth mechanism of MoO₃ nanoribbon was studied by controlling hydrothermal time.The response of MoO₃ nanoribbon to methanol and ethanol before and after ZIF-70 surface modification.

The results show that the ZIF-70/MoO₃ composite has better selectivity for methanol (compared with ethanol) than the unmodified MoO₃ nanoribbon.

The characteristics of this paper: the traditional transition metal oxide gas sensitive material is compounded with the emerging MOFs material, and the traditional material is modified by using the advantages of MOFs material.

Key Words：MoO₃；MOF；gas sensing property；physical fitration

目 录

摘 要 I

Abstract Ⅱ

第1章 绪论 2

1.1 气体传感器概述 2

1.2 金属氧化物气敏传感器的敏感机理 3

1.2.1 敏感机理 3

1.2.2 影响因素 4

1.3 MoO₃气敏材料的研究与发展现状 5

1.4 ZIF-70（MOF）的性质与应用现状 6

1.5 本论文研究意义和研究内容 8

1.5.1 本论文研究意义 8

1.5.2 本论文研究内容 9

2.1 材料的制备 10

2.1.1 材料制备所需的试剂和仪器 10

2.1.2 MoO₃纳米带的制备 11

2.1.3 ZIF-70的制备 11

2.1.4 ZIF-70/MoO₃复合材料的制备 11

2.2 旁热式气敏元件的制作及测试原理 12

2.2.1 旁热式气敏元件的制作 12

2.2.2 旁热式气敏元件测试原理 12

第3章 实验结果与讨论 14

3.1 结构表征 14

3.2 气敏性能 19

第4章 结论与展望 23

4.1 结论 23

4.2 展望 24

参考文献 25

附录1 28

附录2 29

第1章 绪论

1.1 气体传感器概述

气体与人们的生活息息相关，人们对空气质量的关注度也随着生活水平的提高而逐渐上升，特殊情况下为了人身安全，需要对某些易爆或有毒性气体进行检测与监控；另外，在程序控制和实验室分析中也需要进行气体检测^[1]。为满足这些要求，气体传感器应运而生^[2]。气体传感器是一种特殊的装置，它能将肉眼不可视的气体组成成分、浓度等信息转化为可被电子仪器识别的信息，再通过计算机、仪器的信息处理，以可视化的形式展现在人们面前，实现对环境气氛的检测、监控。近年来，全球传感器市场一直保持快速增长趋势，仅2015年一年，中国气体传感器行业产能达到了2630万只，全球气体传感器市场规模达19.6亿美元。根据市场研究机构Yole Développement预测，2021年气体传感器市场将囊括9.2亿美元的市场价值，具有很好的发展前景^[3]。

在具体的应用环境中，气体传感器应该具备多种优点：

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