铌钽基复合氧化物的异质构建及电荷调控用于光热协同去除低浓度气体污染物研究

This project pays attention to the basic scientific problems for removing gaseous pollutants with low concentration, high poisonousness and hard degradation property. By modulating the heterojunction feature, microstructure and defect chemistry, the catalytic performance of nano-metal loaded niobate-tantalate oxides/lanthanide oxides can be well controlled and optimized. Under the guidance of density functional theory, the impacts of the heterogeneous surface feature, electronic structure and built-in electronic field of the catalysts are fully investigated in order to shedding light on the visible light responses, lifetime of photoinduced charge carriers, rules of interface charge migration as well as spatial charge separation efficiency. The principle of the interfacial physical and chemical interaction between the catalysts and gaseous pollutants are also explored. The influence of microstructure and defect chemistry modulation on gaseous adsorption and photo-thermal catalytic activity is studied to uncover the underlying catalytic mechanism. Finally, the relationship between composition, structure and property is acquired. This project may provide a new type of catalyst with high photo-thermal catalytic activity toward gaseous pollutants with low concentration, high poisonousness and hard degradation property. Moreover, this project may also contribute principles for designing and constructing hierarchical nano-catalysts toward environmental remediation and efficient utilization of sources.

本项目针对气体环境中低浓度、高毒性、难降解气体污染物消除中的基础科学问题，通过纳米金属负载的铌钽基半导体/稀土氧化物材料的异质构筑、微观结构和缺陷化学调控实现该类材料催化性能的调控与优化。以密度泛函理论为指导，获得异质表界面特性、电子结构、内建电场调控等对催化剂可见光响应活性、光生电荷寿命、界面电荷迁移规律及空间电荷分离效率的影响规律，阐明该类光催化剂与典型挥发性有机污染物气体分子的相互作用的物理化学行为原理，获得催化剂微观结构调变及缺陷化学调控对气体吸附性能和光热催化活性的影响，揭示副产物产生与消除机理，获得该类材料的催化反应机理，阐明该类催化材料的组成-结构-性能三者之间的相互关系。该项目的实施有望为低浓度、高毒性、难降解气相污染物的去除提供一种高性能催化剂，并为该类材料在纳米催化材料的开发、环境催化治理及资源高效利用与转化等方面的应用提供一定的理论基础和技术支撑。

本项目立足内蒙古自治区重大战略需求和学科发展方向，围绕污染物消除中的基础科学问题，通过异质结构构筑、微观及缺陷化学调控实现催化性能的调控与优化，实现该类材料在环境净化领域中的应用。主要成果有：（1）制备了一系列AgNb1-xTaxO3固溶体，获得了离子掺杂类型、掺杂位点和掺杂浓度对晶相结构、能带位置和功函数的影响，发现其对硝基苯酚还原反应有较高活性；进一步负载CdS量子点后发现Ag/AgTaO3的光催化活性提高了10倍。（2）通过结构及缺陷化学调变实现LaMnO3对抗生素吸附活性的灵活调控，发现抗生素在LaMnO3表面吸附符合准一级动力学模型。（3）构建了Bi修饰S型BiVO4/g-C3N4的三相复合光催化材料，用于模拟全谱太阳光照射下协同高效氧化处理甲醛气体并深入探究了其光催化机理。（4）设计合成了三相双S型光催化功能材料BiVO4/g-C3N4/Bi2O3，用于在模拟全谱太阳光下氧化分解甲醛，发现其具有优异的光催化氧化甲醛的催化活性和高的二氧化碳选择性。(e) 制备了直接S型BiVO4/Fe2O3复合催化剂，在可见光与过硫酸盐(PMS)协同条件下降解四环素，结合DFT理论计算提出了BiVO4/Fe2O3/PMS/Light体系的反应机理。(f) 以CoSn(OH)6立方体为前驱体，通过改变煅烧条件下制备了Co-Sn-O，Co3O4/SnO2，Co2SnO4/SnO2三种复合催化剂用于活化PMS降解50 ppm四环素，发现Co2SnO4/SnO2表现出显著的催化活性以及稳定性。本项目执行期间开发出一系列异质结构催化剂，实现了能带结构和催化活性的灵活调控，各项性能明显提升，并将该系列材料用于环境污染处理，无论在理论研究还是在潜在应用方面都有重要意义。