基于有机氯农药痕量检测的双掺杂ZnO@Ag@SiO2核壳结构的制备及SERS活性研究

Surface enhanced Raman Scattering (SERS) technique has broad application prospects in the field of trace detection of pesticide residue. Specific identification,sensitivity and stability of trace detection of pesticide residue have directly decided by the SERS active substrate. In this project, we ultilize the excellent physical and chemical properties of ZnO nanomaterials, the enhancement effect of precious metal Ag and the protection of SiO2 outer shell to design and build a new type ZnO@Ag@SiO2 core-shell structure as SERS substrate. We dope double elements to improve the SERS activity of the substrate and realize the rapid and highly sensitive detection of organochlorine pesticides. The content consists of the following parts: the synthesis technology of rare earth element and Mg codoped ZnO will be further proved; the influence of doping component and proportion on the optical properties and the related mechanism will be investigated in detail; to realize the synthesis of ZnREMgO@Ag@SiO2 core-shell structure and explore the best preparation technology; the influence of the size of Ag nanoparticle, the thickness of SiO2 outer shell on the SERS activity of the system will be investigated and the related enhanced mechanism will be clarified; Finally, the optimized core-shell SERS substrate will be used to detect the organochlorine pesticides endosulfan and the sensitivity, stability and repeatability of the substrate will be investigated. Our project not only provides a new type of SERS substrate and a reliable method of trace detection of pesticide, but extends the application of surface enhanced Raman technology.

表面增强拉曼(SERS)技术在农药残留痕量检测领域具有广阔的应用前景。SERS活性基底直接决定着农药残留痕量检测的特异性识别、灵敏度和稳定性。本课题拟利用ZnO纳米材料的优异物化性能，贵金属Ag的拉曼增强效应和SiO2的外层保护作用，设计并构建新型的ZnO@Ag@SiO2核壳结构作为SERS基底，并通过双元素掺杂ZnO改善基底的SERS活性，实现对有机氯农药的快速高灵敏度检测。具体内容包括：完善稀土元素和Mg双掺杂ZnO的制备工艺，研究掺杂组分和比例对ZnO性能影响及相关机制；合成ZnREMgO@Ag@SiO2核壳结构，探索最佳制备工艺；研究Ag和SiO2外壳层厚度对该体系SERS活性的影响，揭示增强机理；选用最优化核壳结构基底对有机氯农药硫丹进行检测，对基底的灵敏度、稳定性、重复性进行分析。该课题提供了一种新型的SERS基底，为农药痕量检测提供可靠方法，拓宽了表面增强拉曼技术的应用范围。

表面增强拉曼(SERS)技术在农药残留痕量检测领域具有广阔的应用前景。SERS活性基底直接决定着农药残留痕量检测的特异性识别、灵敏度和稳定性。本课题旨在设计并构建新型的双掺杂半导体核壳结构作为SERS基底，实现对农药的快速高灵敏度检测。主要研究成果如下：一、成功制备了Mg、Eu共掺杂ZnO，Cu、Al共掺杂ZnO，Cu、Co共掺杂ZnO，Sm、Eu共掺杂ZnO，Sm、Eu、La共掺杂ZnO，Nd掺杂ZnO纳米材料，并研究了掺杂元素的组分、掺杂浓度对ZnO纳米材料光、磁性质影响的微观机制。二、核壳纳米复合结构体系的研究：ZnO@Eu2O3，添加了Eu2O3层后，Eu的红光发射比掺杂的样品提高了5.9倍，并提高了ZnO的光催化性能、热稳定性和压力稳定性，是光电器件的潜在应用材料。SiO2-Ag复合型SERS基底，当Ag纳米粒子的尺寸大约是10-20 nm，SiO2层厚度大约是2-5 nm，SERS增强效果最好，该基底最大标准偏差为10.3%，对PATP的检测限为10-7 mol/L，对MBA的检测限为10-8 mol/L。并研究了热处理温度对其形貌和SERS性能的影响，结果表明，退火600度后样品的SERS增强最大，SiO2层不仅可以对拉曼具有较好的增强效果，并且能起到一定的保护作用，提高了SERS基底的稳定性；三、低温合成的八面体Cu2O-Au和Cu2O-Ag核壳结构，增强因子最低值能达到7.2×105。利用溶剂热法合成了Ag包覆Mg掺杂ZnO纳米棒阵列，该基底具有很好的适应性，对4-MBA，4-MPY，4-ATP和福美双都有很好的增强效果，计算得到增强因子为2.53×107。将其进一步用于农药福美双的检测，最低检测限可以达到10-11。由此可见，该课题的研究结果为农药痕量检测提供可靠方法，拓宽了表面增强拉曼技术的应用范围。