基于TiO团簇的化学电阻型气敏传感材料的研究

The cluster materials, which are featured with clear molecular structure, large specific surface area, high ratio of available atom and etc., make their potential in chemiresistive gas sensing. The research of cluster based gas sensing materials have the possibility to solve the problem of traditional nano-sized gas sensing materials in lack of clear relationship between molecular structure and gas sensing performance which significantly hampers the development of high-performance gas sensing materials. However, at present, cluster based gas sensing materials are mainly studied by theoretical calculation and their experimental research is extremely desired. In this project, TiO clusters are selected to study the gas sensing performance towards to NOx and SOx. The research will mainly focus on enhancing their RT sensitivity and selectivity by systematically tuning the molecular structure, functional group at surface and the nanostructure of TiO clusters and their hybrid materials. Through the research of this project, the structure features of TiO cluster based high-performance gas sensing materials could be revealed; TiO cluster based high-performance gas sensing materials will be obtained; the valid relationship between cluster material and gas sensing performance will be summarized. The results obtained in this project will provide a general theoretical guidance for further optimizing sensing material and lay a foundation for developing high-performance gas sensing device.

确定的分子结构，巨大的比表面积，高的原子利用率等特性赋予团簇在化学电阻型气敏传感方面潜在应用价值。团簇基气敏传感材料的研究有望解决传统微纳结构气敏材料由于在分子尺度上的结构与气敏性能的有效关系不清晰无法高效地指导高性能材料开发的难题。然而,目前团簇气敏材料的研究主要集中在理论计算方面，实验方面的工作亟待开展。在本项目中，我们拟选取可通过配位化学的方法实现结构调控的TiO团簇为研究对象，开展金属氧化物团簇对NOx和SOx的气敏性能研究。通过对TiO团簇的分子结构，表面官能团及其复合材料的微纳结构的系统研究解决他们在常温下对目标气体敏感度低和择性差的难题，掌握具有优异气敏性能的TiO团簇的结构特征，获得对目标气体具有高敏感度和高选择性的团簇气敏材料，总结和揭示团簇结构和气敏性能之间的有效关系，为优化化学电阻气敏传感材料提供一般性的理论指导，为高性能气敏传感材料的开发奠定材料和器件基础。

痕量气体的实时检测对于保障人们生命财产安全、降低生产成本提高生产效率和保护环境具有重要意义。确定的分子结构，高的原子利用率等特性赋予团簇在化学电阻型气敏传感方面潜在应用价值。但目前团簇气敏材料的研究极少，并且主要集中在理论计算方向。钛氧团簇（TiOs），具有结构多样、易制备和优异的光电性能，吸引了我们以它们为研究对象开展团簇气敏性能的研究。我们合成了系列不同核数的TiOs，并通过系统气敏测试发现：1）光辅助可大幅度提升TiOs的气敏性能，然而团簇易团聚导致有效利用率低，减小TiOs颗粒尺寸的方法增大了团簇的利用率和与待测物NO2的接触面积，可提升气敏性能；2）受前述研究的启发，将Ti8团簇与有机配体桥连构筑了多孔结构的NH2-MIL-125，解决了团簇分散的难题，大幅度增加团簇利用率和与待测物接触面积，其薄膜器件实现了对硝基爆炸物的ppb级蒸汽的室温检测；3）进一步，将NH2-MIL-125纳米膜外延生长在TiO2纳米线阵列的表面，构筑高效的type-II异质结界面TiO2/NH2-MIL-125，大幅度优化了光活化气敏性能，突破了室温硝基爆炸物的检测极限：实际检测限低至0.8 ppq，比嗅探犬等金标准检测技术优化1000倍；响应时间仅8秒可实现实时检测；具有优异的选择性和抗湿气干扰能力；可实现距离远至8米或者质量低至5毫克样品的非接触检测。通过本项目的支持，三年内在国际学术刊物上发表高质量研究论文12篇，其中影响因子大于10的SCI论文8篇，包括国际顶级期刊Angew. Chem. Int. Ed.（4篇），国内顶级期刊Natl. Sci. Rev.（1篇）以及J. Mater. Chem. A（2篇）。较好完成了项目既定目标，符合本重大研究计划的总体目标要求。