新型敏感材料的设计合成及其在环保方向的应用研究

发布时间：2018-01-30 00:54

  本文关键词： 复合氧化物 聚苯胺 半导体纳米粒子 水滑石 气敏 湿敏　出处：《北京化工大学》2015年硕士论文　论文类型：学位论文

【摘要】：传感器是指能够感受被测信息并将其按一定规律转换为电信号或其它形式信息输出的检测装置,已被广泛应用到工业自动化、医疗诊断、农业、航天等与人类生活和发展密切相关的领域中。按照功能可将传感器分为：光敏、气敏、湿敏、力敏、声敏等类型。其中气敏传感器的敏感材料主要是金属氧化物半导体,具有易于设计、成本低、检测快速等优点,但选择性差,需要进一步对敏感材料优化；湿敏传感器主要敏感材料为有机聚合物类,具有导电性好、结构多样、可用于室温测量等优点,但长期稳定性差,同样需对其性能进行优化。材料复合是经有效改善敏感材料性能的重要方法,因此研究复合敏感材料以提高传感器的气敏、湿敏性能具有重要的现实意义。本文分别针对气敏及湿敏领域的敏感材料存在的问题,制备了两类复合材料,即复合金属氧化物ZnO/CuO/Al2O3的氯代烃气敏材料及CdS/PANI有机无机复合湿敏材料。在气敏体系中采用共沉淀法合成了锌铜铝氢氧化物前驱体,在不同温度下焙烧形成复合金属氧化物ZnO/CuO/Al2O3,研究其对低浓度氯代烃的气敏性能。以氯仿为代表性气体,复合材料的气敏性能随着焙烧温度的升高而降低。同时含有锌、铜、铝三种氧化物且铜含量相对较高的复合氧化物气敏材料ZnCu0.7Al0.6-5O0对氯仿的气敏性能最佳,检测限低、响应迅速。在最佳工作温度200℃下,ZnCu0.7Al0.6-500甚至可以检测浓度低至1 ppm的氯仿。在湿敏体系中,成功将聚苯胺(PANI)引入镉铝水滑石CdAl-LDH层板间,制备得到水滑石结构限域的聚苯胺CdAl-LDH/PANI,经气固硫化反应获得CdS/PANI有机无机复合材料,通过水滑石结构的限域效应,以及进一步的硫化修饰作用,提高了聚苯胺的湿敏性能。湿敏性能研究表明在11%到95%RH整个湿度范围内,CdAl-LDH/PANI具有非常好的线性关系,响应速度快、性能稳定；经硫化修饰后的CdS/PANI材料在整个湿度范围内阻抗可降低4个数量级,响应时间仅为2 s,湿敏性显著提高。因此,水滑石的层板限域作用和硫化修饰两步法,可以有效提高聚苯胺的湿敏性能。
[Abstract]:Sensor refers to the detection device which can feel the measured information and convert it into electrical signals or other forms of information according to certain rules. It has been widely used in industrial automation, medical diagnosis, agriculture. Aerospace and other fields closely related to human life and development. According to the functions of sensors can be divided into: Guang Min, gas sensitivity, humidity sensitivity, force sensitivity. The sensitive materials of gas sensors are mainly metal oxide semiconductors, which have the advantages of easy design, low cost and fast detection, but the selectivity is poor, so the sensitive materials need to be optimized further. The main sensitive material of humidity sensor is organic polymer, which has good electrical conductivity, diverse structure and can be used in room temperature measurement, but the long-term stability is poor. Material compounding is an important method to improve the properties of sensitive materials, so the study of composite sensitive materials is to improve the gas sensitivity of sensors. Humidity sensing properties have important practical significance. In this paper, two kinds of composite materials have been prepared, aiming at the problems of sensitive materials in the field of gas sensitivity and humidity sensitivity. That is, chlorinated hydrocarbon gas sensing material of composite metal oxide ZnO/CuO/Al2O3 and CdS/PANI organic-inorganic composite humidity sensitive material. Zinc, copper and aluminum hydroxide were synthesized by co-precipitation method in gas sensing system. Precursor. The composite metal oxide ZnO / CuO / Al _ 2O _ 3 was calcined at different temperatures to study the gas-sensitivity of ZnO / CuO / Al _ 2O _ 3 to low concentration chlorinated hydrocarbons. Chloroform was used as the representative gas. The gas-sensing properties of the composites decrease with the increase of calcination temperature, and also contain zinc and copper. The gas sensing material ZnCu0.7Al0.6-5O0 with three kinds of aluminum oxides and relatively high copper content has the best gas sensitivity to chloroform and the detection limit is low. Under the optimum operating temperature of 200 鈩，

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