项目名称： 基于沸石内络合反应的阻抗型氨气传感器研究

项目编号： No.61501271

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 无线电电子学、电信技术

项目作者： 郑雁公

作者单位： 宁波大学

项目金额： 22万元

中文摘要： 对汽车尾气中氮氧化合物（NOx）排放的控制，采用的是加装选择性催化还原（SCR）系统来分解NOx。SCR系统中，还原剂氨气的浓度需要准确的检测和监控。但在对SCR氨气传感器的研究中，传感器的选择性始终未能满足应用要求。本项目提出了一种基于沸石内络合反应的阻抗型氨气传感器。通过氨气与沸石内金属阳离子之间的络合反应，引起沸石阻抗的变化。这种新的气敏机理可以使传感器在SCR系统中有效地避免其它气体的干扰。首先，通过研究沸石内络合反应与温度之间的关系，界定该反应随氨气浓度可逆变化的温度范围。其次，重点研究络合反应对沸石离子电导的作用机理，揭示沸石类型，阳离子种类等与气敏响应之间的关联，完善相关理论并建立气敏机理模型。最后，SCR模拟环境下，测试传感器的气敏性能。此外，为减小水对传感器的干扰，通过制备高硅铝比沸石以提高疏水性，或解析阻抗谱而优化测量参数来降低水的影响。本项目的实施将研制出具有高灵敏度和选择性的SCR氨气传感器。

中文关键词： 沸石；络合反应；氨气传感器；交流阻抗谱

英文摘要： In order to control and significantly reduce NOx emission for commercial vehicles, an SCR (Selective Catalytic Reduction) exhaust gas after-treatment system, which uses ammonia as a reductant, is introduced to decompose NOx. A gas sensor is required to monitor and detect the concentration of ammonia in the SCR system. Several attempts for ammonia sensor in the SCR system have been reported in the literatures, but one general disadvantage with respect to the cross-sensitivity hinder the sensors for practical application. This project propose an impedimetric ammonia sensor based on intrazeolitic complex reaction, whose impedance response is depend on the interaction between ammonia and intrazeolitic metal cations. This novel gas-sensing mechanism could effectively avoid the interference from the others in the SCR system. Firstly, to define the temperature range that the intrazeolitic complex reaction become reversibility, we would study the relationship between intrazeolitic complex reaction and temperature based on different metal cations and zeolite. Secondly, focused research addresses the question: how does the complex reaction influence the ionic conductivity of zeolite? The influence mechanism could be confirmed by understanding the correlation between the different zeolite, metal cations and their gas-sensing response to ammonia. The gas-sensing model based on the intrazeolitic complex reaction will also be presented by analyzing the experimental results. Finally, the sensor is going to be tested in a simulated SCR environment. Moreover, expected problem relate to the interference of water is going to be solved by two methods: zeolite with high Si/Al ratio is prepared to enhance its hydrophobicity; measuring parameters is optimized to decrease the influence of water based on the analysis the components of impedance spectroscopy of sensors. In summary, the project will make a unique contribution to develop and research ammonia sensor with high sensitivity and selectivity in the SCR system.

英文关键词： zeolite;complex reaction;ammonia sensor;impedance spectroscopy