华中科技大学硕士学位论文
摘要
二氧化氮（NO2）是一种具有强烈刺激性气味和毒性的红棕气体。作为一种重要的空气污染物，NO2对人体和环境都有很大危害。因此，我们很有必要开发高性能的气敏传感器以实现对NO2的有效检测。目前常见的基于简单金属氧化物的气体传感器均存在各自的局限性，如工作温度高，选择性差等。因此，研究新的气敏材料体系与新的形貌结构迫在眉睫。本文以钙钛矿型复合金属氧化物为研究对象，通过溶胶凝胶法、MOF模板法、静电纺丝法等多种方法合成了不同形貌的纳米材料，并深入研究了材料的组份与形貌对其NO2气敏性能的影响。 第一章介绍了开发NO2传感器的意义及研究现状，简单介绍了应用于NO2传感器的半导体纳米材料，同时介绍了钙钛矿结构复合金属氧化物的基本性质及其在气敏传感器上的应用。
第二章采用溶胶凝胶法制备了锰酸镧（LaMnO3）纳米颗粒，并利用丝网印刷法制备了厚膜传感器，测试了器件对NO2的响应特性，并研究了掺杂对其NO2敏感特性的影响。 第三章采用MOF模板法合成了直径约2μm的铁酸钐（SmFeO3）空心多孔微球。通过滴涂法以FTO为衬底制备了NO2气敏传感器。器件在200℃下表现出了出的NO2敏感特性：对200ppb的NO2有10.2的响
应，响应回复时间分别为369s和478s，同时器件对低至50ppb的NO2仍有明显的响应。器件优良的NO2敏感特性应该得益于多孔的表面形貌对NO2的夺电子吸附反应的促进。
第四章采用静电纺丝法制备了宽约300nm的SmFeO3多孔纳米带。材料在室温下对5ppm的NO2表现出明显的响应，验证了SmFeO3多孔纳米带在低温下检测低浓度NO2的潜质。
最后对本文获得的结论及仍然存在的问题做出了总结，并对相关工作以后的发展做出了展望。
关键词：NO2传感器；LaMnO3；SmFeO3；溶胶凝胶法；MOF模板法；静电纺丝法
华中科技大学硕士学位论文
Abstract
薄膜电晕处理机
Nitrogen dioxide (NO2) is a poisonous gas with red brown color and pungent odor at room temperature. As a major atmospheric pollutant, NO2 is harmful to human health and environment. Therefore, it is essential to develop high performance sensors for effective detection of NO2. The current NO2sensors based on simple metal oxide have many limitations, such as high working temperature and poor selectivity. Therefore, the research of new material and new morphology is critical. In this work, perovskite-structured metal oxides were chosen as the sensing material. Nanom
aterial with different morphologies was prepared by sol-gel method, MOF self-templating method, and electrospinning method. We studied the effect of material and morphology on NO2sensing properties of perovskite-structured metal oxides.
In Chapter 1, the significance and current status of NO2sensors were introduced. Metal oxide semiconductors (MOS) nanomaterials applied to NO2 sensors were described. The properties and gas sensor applications of perovskite-structured metal oxides were also discussed.
In Chapter 2, LaMnO3 nanoparticles were prepared by sol-gel method. LaMnO3 thick films were prepared from these nanoparticles by screen-printing technology. The NO2 sensing properties of the thick film were characterized. In addition, the effect of doping was studied.
In Chapter 3, Porous hollow microspheres of SmFeO3 were prepared from a simple process involving a metal organic framework (MOF) compound as the templating precursor. With a diameter of about 2 μm, these hollow-centered microspheres are formed by nanoporous thin walls of SmFeO3. Chemoresistive gas sensors based on these microspheres exhibits excellent sensing performance on NO2at 200 °C, including high sensitivity (response of 10.2 under 200 ppb) with detection limit as low as 50 ppb, high selectivity, and reasonably short time for response and recover
y (369 s/478 s). The superior sensing response over other SmFeO3-based NO2sensors can be ascribed to the electron-accepting reactions during NO2adsorption, which is facilitated by the special morphological features of the microsphere.
如图是某水上打捞船
挤爆胶囊In Chapter 4, mesoporous SmFeO3 nanobelts with width of 300 nm were prepared by
华中科技大学硕士学位论文
electrospinning. The nanobelts exhibits obvious response to 5 ppm NO2at room temperature, which verified the potential of the mesoporous SmFeO3nanobelts for the detection of low concentrations of NO2 at low temperature.
The last chapter gives a summary and outlook of this work.
Keyword: NO2 sensor; LaMnO3; SmFeO3; Sol-gel method; MOF self-templating method;
electrospinning method
华中科技大学硕士学位论文
目录
摘要............................................................................................................. I I 目录.......................................................................................................... IV 1. 绪论. (1)
1.1 大气环境中的二氧化氮 (1)
1.2 气敏传感器概述 (1)
1.2.1 气敏传感器的分类及工作原理 (1)
1.2.2 电阻式半导体气体传感器性能指标 (2)
大电容1.3 用于气敏传感器的金属氧化物半导体纳米材料 (3)
1.3.1 零维纳米材料 (4)
1.3.2 一维纳米材料 (4)
1.3.3 二维纳米材料 (5)
1.4 钙钛矿类材料及其在气敏方面的应用 (6)
1.5 本课题的意义与内容 (8)
2. 锰酸镧纳米颗粒的NO2气敏性能研究 (9)
2.1 引言 (9)
2.2 实验准备 (9)
2.2.1 实验试剂 (9)
2.2.2 实验试剂 (10)
2.2.3 实验方案 (11)
2.3 LaMnO3纳米颗粒与厚膜气敏传感器的制备 (11)
2.3.1 溶胶凝胶法制备LaMnO3纳米颗粒 (11)
高压氮气压缩机
华中科技大学硕士学位论文
2.3.2 丝网印刷法制备LaMnO3厚膜气敏传感器 (11)
2.4 LaMnO3纳米颗粒与厚膜气敏传感器的表征 (13)
2.4.1 LaMnO3纳米颗粒的XRD分析 (13)
2.4.2 LaMnO3粉末的TEM分析 (13)
2.4.3 LaMnO3厚膜传感器的XRD分析 (14)
2.4.4 LaMnO3厚膜传感器的SEM分析 (15)
2.5 LaMnO3厚膜气敏传感器的NO2气敏性能 (16)
2.6 La1-x Sr x MnO3厚膜气敏传感器的NO2气敏性能 (17)
2.7 La1-x Sr x MnO3的NO2气敏机理 (21)
2.8 本章小结 (22)
3．铁酸钐空心微球的NO2气敏性能研究 (23)
3.1 引言 (23)
在线销售系统
3.2 实验准备 (25)
3.2.1 实验试剂 (25)
3.2.2 实验仪器 (25)
3.2.3 实验方案 (26)
3.3 SmFeO3空心微球及传感器的制备 (26)
3.3.1 SmFeO3空心微球的制备 (26)
3.3.2 气敏传感器的制备 (27)
3.4 SmFeO3空心微球与气敏传感器的表征 (27)
3.4.1 前驱体热分析 (27)
3.4.2 SmFeO3空心微球的XRD分析 (28)
3.4.3 SmFeO3空心微球的XPS分析 (29)
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