基于含氟聚苯胺基纳米复合材料的室温高灵敏NO2气敏传感器研究

Nitrogen oxides NOx generated from automobile exhaust and thermal power plant is one of the major atmospheric pollutants. Up to now, the NOx concentration is determined by firstly catalytic oxidizing all the components of the NOx into NO2, and then testing the NO2 concentration by expensive and complex Saltzman method or chemical luminescence method. It is of great significance to develop simple and practical NO2 gas chemical sensors for environmental monitoring. Comparing with traditional inorganic oxide semiconductor material, conjugated polymer gas sensor has the advantages of low work temperature, low energy consumption, good reversibility under ambient temperature and pressure, as well as easy to miniaturized design. However, it also has the disadvantages of poor long-term environmental stability for and vulnerable to air humidity. In this work, the fluorinated polyaniline nanofibers with higher stability and resistance to humidity will be firstly synthesized. The influence of the morphology, the fluorine content of the polymer on the response characteristics to NO2 will be explored. The response characteristics to NO2 will be optimized by preparing fluorinated polyaniline-nanocarbon composites or modified by metal oxide nanocrystallines. The influence of the conjugated effects between polymers and carbon as well as the synergistic effect of the nanocrystallines-fluorinated polyaniline heterojunctions on the response characteristics to NO2 will be explored. The sensor for NO2 with concentration lower than 5 ppm will be designed and fabricated.

来源于汽车尾气和火电厂的含氮氧化物NOx是主要的大气污染物之一。目前主要通过将NOx的各种成分全部催化氧化成NO2，再利用昂贵复杂的Saltzman法或化学发光法来测定NO2浓度从而计算NOx浓度。研究价格低廉、简便实用的NO2气体化学传感器对于环境监测具有重要意义。与传统的无机氧化物半导体气敏材料相比，共轭高分子气敏传感器具有工作温度低、能耗低、常温常压下可逆性好、可微型化设计等优点，但存在长期环境稳定性差、易受空气中湿度干扰等缺点。本研究工作首先合成具有较高稳定性、抗湿度干扰的含氟聚苯胺纳米纤维气敏材料，揭示含氟聚苯胺形貌、氟含量等对NO2响应特性的影响规律；通过与纳米碳材料复合以及氧化物纳米晶修饰优化材料对NO2响应特性，揭示碳材料与共轭分子链之间的共轭效应以及纳米晶修饰含氟聚苯胺形成的异质结对NO2气体响应特性协同效应机理。制成5 ppm以下NO2气体检测的传感器元件。

来源于汽车尾气和火电厂的含氮氧化物 NOx 是主要的大气污染物之一。目前主要通过将 NOx 的各种成分全部催化氧化成 NO2，再利用昂贵复杂的 Saltzman 法或化学发光法来测定测试 NO2 浓度从而计算 NOx 浓度。研究价格低廉、简便实用的 NO2 气体化学传感器对于环境监测具有重要意义。与传统的无机氧化物半导体气敏材料相比，共轭高分子气敏传感器具有工作温度低、能耗低、常温常压下可逆性好、可微型化设计等优点，但存在长期环境稳定性差、易受空气中湿度干扰等缺点。.本项目开展SnO2修饰TiO2纳米带、纳米SnO2修饰石墨烯、SnO2修饰聚3-氟苯胺纳米纤维、聚3-氟苯胺修饰氧化石墨烯、PEDOT纳米结构以及纳米SnO2修饰聚萘胺纳米管的合成以及NO2气敏特性研究。SnO2修饰TiO2纳米带在220 oC下对50 ppm NO2气体响应灵敏度19.6，对10 ppm NO2气体响应灵敏度7.8，对50 ppm水蒸气相应灵敏度 4.6。纳米SnO2修饰石墨烯200 oC下对50 ppm NO2气体响应灵敏度21.2，对5 ppm NO2气体响应灵敏度10.1，对50 ppm水蒸气相应灵敏度 5.1。SnO2修饰聚3-氟苯胺纳米纤维80 oC下对50 ppm NO2气体响应灵敏度9.9，对10 ppm NO2气体响应灵敏度4.8，对50 ppm水蒸气相应灵敏度 <2，几乎不响应。聚3-氟苯胺修饰氧化石墨烯80 oC下对50 ppm NO2气体响应灵敏度11.5，对5 ppm NO2气体响应灵敏度5.8，对50 ppm水蒸气相应灵敏度 2.9。PEDOT在80 oC下对50 ppm NO2气体响应灵敏度12.6，对5 ppm NO2气体响应灵敏度4.8，对50 ppm水蒸气相应灵敏度 5.6。聚α-萘胺（PNA）为纳米管结构，80 oC下对对5 ppm NO2气体响应灵敏度2.8。SnO2修饰的聚α-萘胺纳米管在80 oC下对5 ppm NO2气体响应灵敏度11.7。.制备了填充型聚合物气敏材料：聚合物PVDF—导电填料纳米炭黑—共轭高分子（聚3氟苯胺、聚α-萘胺）材料体系，实现对NO2和NO气体的分别相应。设计制作了三仓三探头低温检测NOx模型器件。.本项目实现5 ppm 以下NOx良好响应，以利于在气体检测领域的推广应用，与我国当前的社会发展需求相吻合。