复合光催化材料的功能设计、模块化组装及构效关系研究

摘要

光催化技术是目前研究的热点课题之一，但作为光催化技术研究的核心内容-光催化材料的设计理论与功能组装等方面相对薄弱。该研究拟以材料复合功能设计为目标，模块化组装为手段，研究聚氧钛铌酸盐纳米片－过渡金属离子以及金属氧化物复合光催化剂的设计、组装与构效关系。采用高温固相、聚合－络合等方法合成了规整的层状聚氧钛铌酸盐异构体如KTiNbO5和K3Ti5NbO14等作为光催化材料的基本组元，选用合适的前驱物如硝酸盐或羰基制备对有机硫化物具有吸附作用的吸附模块如Ni2+、Fe3+等离子和NiO和Fe2O3等氧化物，研究模块构建与协同组装技术，构建复合功能光催化材料；以硫醇/硫醚为探针反应物，研究复合光催化材料中有机物富集与光催化氧化功能的耦合。通过XRD、TEM、LRS、UV-vis DRS和FT-IR等表征技术对复合光催化材料的结构、光化学特征以及催化作用进行表征；并探讨了反应机理。结果表明，随着纳米片单元中Ti/Nb的变化，光谱响应特征出现明显的规律，层间过渡金属离子与价带电子轨道发生明显的相互作用改变了带隙能量。氧化物柱撑中前驱物直接影响材料的结构与组元之间的相互作用，并进而影响材料的性能。%Photocatalytic technology is one of the hot topics in current research. However, the theoretical design and functional assembly of the photocatlytic materials are relatively weaker. The purpose of this study is to design composite functional materials using modular assembly technology, as the functional design theory, modular assembly technology and structure-activity relationship of the layered polyoxo-titanoniobate and cation or oxide nano-crystals of transition metal were researched systematically. The layered polyoxo-titanoniobates such as KTiNbO5, and K3Ti5NbO14 etc, as basic modular, which were prepared by polymerization complex method or solid state reaction method. The adsorption modular that adsorbed the organic sulfides, such as Ni2+ and Fe3+ ions, and NiO and Fe2O3, which were prepared by decomposition of its nitrate or carbonyl complexes. The composite functional photocatalytic materials were built by the modular building and colaborative assembly technology. The adsorption and photocatalytic activity was evaluated using ethyl mercaptan/dimethyl sulfide as the probe molecule. X-ray diffraction (XRD), Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), and Fourier transform infrared spectroscopy (FT-IR) etc were used to characterize the structure feature and photochemical properties of these composites, and the reaction mechanism also was suggested. The results show that the characteristics of spectral response appear regularity changes with the changes of Ti/Nb of the nanosheet unit. The significant interaction between the transition metal ions of interlayer and the valence band orbital changes the band gap energies, and the preparation method of oxide pilared precursors directly affected the interaction between material structure and the modular units, and further influence the photocatalytic properties of materials.