(RGO/TiO2)/SnO2异质结的构筑、分子印迹修饰及其在光电检测痕量气氛TNT中的机理和应用基础研究

To realize the specific and rapid response to trace amount trinitrotoluene (TNT) vapor, it is proposed to explore an optoelectronic sensing method which combines photodetection and molecular imprinting technique. We will try to obtain (rGO/TiO2)/SnO2 hetrojunction which composes rGO with excellent electrical conductivity, nanostructure TiO2 with high photocatalytic capability and SnO2 which is chemical stable and can further improve the photocatalytic capability of TiO2. The corresponding optoelectronic sensor will be explored further. The optimized hetrostructure is considered to have high photocurrent, more sites for the occur of photocatalytic reaction and more efficient electron-hole seperation. The anti-jamming ability of the sensor will be improved by molecularly imprinting a layer of TNT MIPs film on the surface of the hetrojunctions. The secific response towards TNT and the ultrahigh sensitivity of the sensor will be realized through controlling the number of the imprinting sites, the film thickness and the porosity of the film. The underlying charge transfer mechanism and the influence of the MIPs layer towards the photocurrent in the process of optoelectronic sensing on TNT will be discussed. The analysis of the sensing mechanism will provide a silid theoretical basis for optoelectronic sensing. This research will provide a theoretical and experimental basis for the specific optoelectronic sensing of trace amount TNT and shed light on the design and synthesis of optoelectronic sensing materials for organic vapor phase explosives.

为实现对气氛TNT分子专一、快速、痕量检测，本项目将利用光电检测技术与分子印迹技术相结合的手段开辟一种光电检测痕量气氛TNT的方法。设计将具有优异导电特性的rGO、高催化活性的纳米TiO2，以及能够进一步提高光催化活性且化学性质稳定的SnO2三者相结合，构建(rGO/TiO2)/SnO2纳米异质结光电纳米材料和传感器。优化其形貌、结构等参数，获得具有大的光电流响应、多的催化氧化位点以及高的电子-空穴分离效率特征的异质结。综合调控异质结表面分子印迹层的印迹位点数目、膜厚、孔隙率等结构参数，增强传感材料的抗干扰能力，实现对TNT分子专一检测并提高灵敏度。明确TNT气氛浓度与光电流响应时间和强度之间的依赖关系。深入探讨异质结构在光电检测TNT分子过程中，电子传递的本质以及分子印迹层对电流变化的影响。本研究将为光电专一检测痕量气氛TNT提供理论和实验依据，为光电传感材料的设计和制备提供新的思路。

本项目通过rGO/氧化物异质结构、氧化物结构改性及传感器阵列构建，以光电传感方法及分子印迹技术为手段，实现对了TNT分子或其催化分解产物NO2的快速、识别检测。构建了rGO/TiO2、SnO2纳米花、rGO/TiO2/SiNWs等体系，综合考量了材料体系的制备方法、传感器结构对TNT气氛或其典型催化分解产物NO2的检测性能，达到了高灵敏（0.77-9 ppb）、快速（数秒到几十秒）检测目标气氛的目标。通过光电检测理论、光电传感器构建、典型分子印迹（3-氨丙基三甲氧基硅烷APTS）特异性检测，提高基础体系的检测灵敏度和识别性，达到了较专一检测TNT的目标。同时，尝试了其它氧化物结构改性并用于TNT气氛识别检测，如纯相氧化物（In掺杂ZnO、过渡金属掺杂ZnO），ZnO/rGO肖特基异质结，CdS/ZnO核壳光电异质结，并通过表面态缺陷调控及光电传感检测方式进一步提高检测灵敏度，通过构建传感器阵列的方式代替了分子印迹技术专一性检测TNT气氛的策略，达到了对TNT的识别性检测。并且，深入挖掘了检测体系设计与检测性能之间的内在机理。.项目在传感材料设计、传感原理设计、传感器构建方面的工作具有原创性，对于痕量爆炸物气氛及其它气氛如NO2等的检测具有重要的参考价值。相关成果发表在Adv. Funct. Mater.、Small、Nanoscale等材料领域知名期刊，两篇文章被选为杂志卷首插画发表，3篇文章被“MaterialsViews中国”亮点报道。项目负责人因在面向爆炸物气氛检测的电学传感方法方面发展了新的解决方案，获得2016年度中国仪器仪表学会青年科技人才奖。