基于新型多孔金属氧化物的增强型气敏传感器设计

Novel porous metal oxides as a result of their characteristics of rich pores, high specific surface, and high porosity will provide a promising application for the design and fabrication of enhanced gas sensors to determine the hazardous gases. In our project, template method and hydrothermal method will be used to synthesize various porous metal oxides with controllable pore sizes. The effect of the aperture distribution on the gas response and the sensing selectivity of the porous materials will be discussed to improve the performance of sensor. The relationship among the sensing property, preparation parameter, microstructure and surface composition will be found. According to the required sensing properties, the porous structures of metal oxides will be tailored. Precious metal loading/doping and aftertreatment technologies will be used to regulate the surface defect, so as to enhance the interaction between the porous metal oxides and the precious metals and increase the number of the active sites of the sensing material, which will result in a lower working temperature and a higher response of the sensing material. Moreover, surface functionalized modifications will be adopted to realize the directionally selective detection of the toxic gases on the basis of the different interactions between the various modified groups with the detected gases. In addition, combining with different in-situ characterization technologies，absorbed-desorbed species of the detected gases on the porous metal oxides surface will be investigated in order to inquire into the real reaction processes and understand the sensing mechanisms from the atomic level. Therefore, our results will be helpful to develop the relative theory and explain the real sensing mechanism, and can provide technology and theory supports for the fabrication and practical application of the novel gas sensor. Additionally, our project will promote the development of environmental analytical technology. and further satisfy the high sensitivity, selectivity and stability requirements for gas sensor.

新型多孔金属氧化物由于具有孔道丰富、比表面积大、孔隙率高等特点，为实时监测有毒有害气体的增强型气敏传感器设计提供了基础。本项目将采用模板法、水热法等技术制备不同种类的多孔金属氧化物，通过对材料孔径分布的可控调节研究不同孔径对于材料气敏响应、气敏选择性的影响，深入分析材料多孔结构及表面组成与其气敏性能的关系，以增强气敏元件性能为导向优化材料结构。通过贵金属负载/掺杂、表面缺陷调控，增强材料与贵金属的相互作用，增加材料表面活性位点数目，提高材料气敏响应，降低材料气敏工作温度。通过表面功能化修饰，利用材料表面各类修饰基团与待测气体之间的相互作用，实现材料的定向选择性检测。借助原位表征手段在线分析待测气体在材料表面的吸脱附物种，推测材料与待测气体的相互作用过程，从原子水平上理解气敏响应机制。项目研究结果有利于确定真实的气敏响应机理，为气敏元件的实际应用提供理论支持，促进环境检测技术的发展。

本项目针对传感材料仍然面临着灵敏度低、工作温度高、稳定性差等关键问题，发展工艺简单环保节能的制备孔道丰富比表面积大孔隙率高的纳米金属氧化物方法，开发了提高材料传感性能的技术，通过元素负载掺杂、高温退火、气氛处理、材料复合等改性方法进行材料表面功能化修饰，对不同种类金属氧化物传感材料的形貌、表面缺陷和活性物种含量进行精细调控，优化设计了增强型金属氧化物传感器，深入分析材料多孔结构及表面组成与其气敏性能的关系，从原子水平深入解释金属氧化物的传感机制，为增强型纳米金属氧化物传感器实际应用提供了技术支持和理论依据。创新点主要有：①针对多孔金属氧化物的种类还不够丰富，三维有序大孔氧化物等材料在气敏传感方面应用少的现状，通过优化实验条件，实现了比表面积大、孔径分布均一的不同种类多孔金属氧化物的可控制备，通过贵金属负载/掺杂、表面缺陷调控对材料进行改性研究，材料使用稳定性好，将它们运用于气敏传感器的设计既具有方法创新也具有应用创新；②针对半导体金属氧化物传感元件的选择性不理想，往往不能对某一类气体达到专一响应的现状，通过优化材料形貌尺寸和孔道结构，研究多孔材料与掺杂/负载金属相互作用，以增强气敏元件性能为导向修饰金属氧化物材料，增加材料表面活性位点数目，提高了材料气敏响应和对于待测气体分子的选择性，降低材料气敏工作温度，有利于气敏元件的实际应用。成果的科学意义体现在：①改进/开发了高性能一维（棒、线状）、二维（多孔膜结构、纳米片）、三维多孔结构的半导体氧化物及掺杂复合传感材料的可控制备方法；②拓展了电阻型金属氧化物传感分析方法，构建了一系列选择性稳定性好的气体传感器，实现低温/室温条件下对低浓度甲醛、丙酮、乙醇、二甲苯、三乙胺、H2、NO2、CO等有毒有害物质高灵敏快速定向检测。