【作者】 郑伟；

【导师】 王策；

【作者基本信息】 吉林大学 ， 高分子化学与物理， 2010， 博士

【摘要】 由于一维纳米材料具有优异的物理、化学特性,因此使其在光电器件,生物医药,催化传感等方面有着广泛的应用。最近研究表明基于一维纳米金属氧化物的气敏传感器具有更优异的气敏性能,开发研制新型一维纳米材料是改进气敏性能的有效方法。静电纺丝技术操作简单、成本低廉是目前被公认的一种能快速生产一维纳米材料的技术。本论文对基于电纺纳米纤维为气敏材料的甲醇、乙醇传感器进行了系统的研究,主要分为以下四个部分:（1）利用静电纺丝技术结合热处理过程制备了氧化铁（α-Fe₂O₃）纳米纤维。研究结果表明:α-Fe₂O₃纳米纤维对乙醇表现出较好的气敏性能,但是灵敏度有待提高。（2）基于相同的方法制备出氧化铟（In₂O₃）纳米纤维及其复合纤维。纯的In₂O₃纳米纤维对乙醇的灵敏度很高,响应恢复时间也很快,这初步解决了α-Fe₂O₃纳米纤维对乙醇灵敏度低的弱点。利用液相法在具有良好气敏性能的氧化铟纳米纤维表面修饰Pt纳米粒子,研究表明此传感器对有毒气体硫化氢有很好的响应;掺杂适当的氧化物是提高气敏性能的又一有效途径。因此,选择在气敏方面有着良好性能的氧化锡与氧化铟复合,制备出铟锡复合纳米纤维（In₂O₃/SnO2）,复合纳米纤维对甲醇具有很好的响应。（3）稀土金属氧化物是重要的工业原料而且有很好的催化性能。因此,选择三种具有代表性的氧化物La₂O₃,Eu₂O₃,CeO2掺杂氧化铟（In₂O₃）纳米纤维以提高对甲醇的响应。实验表明2% Eu₂O₃/In₂O₃复合纤维对甲醇的气敏性能最好。（4）制备钙钛矿型（ABO3）金属氧化物纳米纤维,研究LaFeO3,LaCoO3,LaInO3对甲醇的气敏性能。实验结果表明:在这三种钙钛矿型稀土复合纤维中铁酸镧（LaFeO₃）纳米纤维对甲醇有最好的响应,而且在气体的选择性方面也有一定改善。既可以通过改变钙钛矿中B位原子的种类来改变气敏性能,也可以通过改变工作温度来实现对某种气体的选择性。更多还原

【Abstract】 Metal oxide thin film gas sensors have been widely used in today’s industrial production in the gas detection, environmental protection, the atmospheric monitoring, the detection of alcohol in traffic safety, the public safety of the toxic gas detection, combustible gas as well as fires warning. However, they usually suffer from several critical limitations such as relative low sensitivity, long response and recovery time and poor selectivity. Along with industrial development and technological advances, it is difficult to meet the requirements of modern industry. Therefore, it requires developing new gas-sensing materials, designing the new structure of the sensor to solve these problems. The rapid development of nanotechnology and nano-materials with nano-effects makes great success in the improvement of gas sensors. With larger surface area, smaller size than the bulk material, sensitive material in a nano-scale can significantly enhance the sensitivity of the sensor performance.One-dimensional （1D） material with excellent physical and chemical properties has a wide range of applications in the optoelectronic devices, bio-medicine, catalysis and sensor. Recent studies have shown that 1D metal oxide-based gas sensor has more excellent gas-sensing properties. Thus development of a new 1D material is an effective way to improve gas-sensing properties. In all the methods and technology to prepare 1D nanomaterials, electrospinning technique is most simple and inexpensive. It is to be recognized as a fast 1D nanostructures of production technology. Unfortunately, there are few reports on the gas sensor based on electrospun nanofibers. In this thesis, the sensors based on electrospun metal oxide nanofibers have been investigated systematically. The thesis is divided into the following four parts:（1）α-Fe₂O₃ ceramic nanofibers were prepared by electrospinning and followed by calcination. The experimental results exhibit that our product shows good characteristics to ethanol vapor. In particular, the sensor’s response and recovery time is excellent, response time and recovery is 3 s and 5 s, respectively. However, the sensitivity needs to be improved.（2） In₂O₃ nanofibers have been fabricated by electrospinning, followed by calcination in air at 700 ?C. The sensor based on the as-prepared In₂O₃ nanofibers showed high response, fast response and recovery time towards ethanol gas. The weakness and low sensitivity to ethanol of the sensor based onα-Fe₂O₃ nanofiber has been initially solved. Noble metals are widely used in catalysis and gas sensing performance could be enhanced by doping the appropriate noble metals. In order to improve the properties of the sensor, we presented a simple and effective solution route to deposit Pt nanoparticles on electrospun In₂O₃ nanofibers for H2S gas detection and exhibited excellent gas sensing properties. In the previous studies, too little attention has paid to methanol which is a toxic substance and important industrial raw materials. Therefore, the study of methanol sensor has enormous and commercial value. In order to develop a methanol sensor, nanofibers in the In₂O₃-doped SnO2 appropriate to improve the response for methanol have been fabricated. Experiments show that when the content of In₂O₃ 25% in the composite （In₂O₃/SnO2）, which shows the best response for methanol, 600 ppm, the sensitivity is up to 130, response and recovery time is 8 s and 15 s, respectively.（3） Rare earth oxides are important industrial raw material which has a good catalytic performance. Therefore, three representative oxides, La₂O₃, Eu₂O₃, CeO2 were used as additive-doped indium oxide In₂O₃ nanofibers to enhance the response of methanol. Experiments show that the 2% Eu₂O₃/In₂O₃ composite nanofiber had the best performance for methanol gas. The sensor sensitivity is 5.3 when methanol concentration is 3 ppm. With the methanol concentration increased to 400 ppm, the sensitivity is actually up 834.（4） Perovskite-type （ABO3） metal oxide nanofibers were prepared to study the LaFeO3, LaCoO3, LaInO3 gas-sensing properties for methanol. Experimental results show that LaFeO3 composite nanofibers have the best responses on the methanol among the three perovskite-type nanofibers. When the concentration of methanol is 500 ppm, the sensitivity is 163, the response and recovery time is 12 s, 21 s （average）. The selectivity can be improved not only by changing the types of atoms in the B but also by changing the operating temperature.更多还原