纳米ATiO3(A=Ca, Sr, Ba)表面氧空位调控及其光催化去除环境氮氧化物性能与机理研究

Nitric oxides (NOx) are one of the primary gaseous pollutants in air that lead to the occurrence of haze events. With the continuous increase of automobiles and burning sources in cities, the control of NOx emission still exist as a critical issue which needs to be solved. This project intends to study the photocatalytic conversion of NOx at room temperature and pressure. Our previous investigation shows that the perovskite strontium titanate (SrTiO3) nanomaterial exhibited excellent adsorption and photocatalytic performance for NOx at sub-ppb level (Qian Zhang et al., 2016). Further in this study, we propose to modulate the formation of oxygen vacancies on the surface of ATiO3(A=Ca, Sr, Ba) nanomaterials, with the aim to enhance photocatalytic removal of NOx and suppress the release of NO2. The in situ spectral characterization and density functional theory calculation will be employed to study the mechanism of photocatalytic NOx conversion over defect engineered ATiO3(A=Ca, Sr, Ba), and key active sites will be identified. The main environmental factors influencing the NOx removal efficiency will be elaborated, and conversion route be established. This project will explore the fundamental mechanism of NOx photocatalytic conversion, and provide novel technique for NOx reduction by realizing the effect of nano-catalytic material on air pollutant conversion at ambient conditions.

氮氧化物（NOx）是导致城市灰霾发生的重要气态污染物之一，伴随着城市机动车及其他燃烧源排放的持续增加，NOx的控制依然为当前大气污染控制的难题。本研究拟针对环境大气中的低浓度NOx，开展常温常压下光催化技术对NOx的转化机制研究。前期研究表明纳米SrTiO3对NOx具有较好的吸附催化性能（Qian Zhang et al., 2016），本研究拟在此基础上调控纳米ATiO3（A=Ca,Sr,Ba）表面氧空位形成，提高NOx光催化活性及产物选择性。采用原位光谱表征与密度泛函理论计算研究氧空位纳米ATiO3（A=Ca,Sr,Ba）表面NOx的迁移转化规律，揭示吸附及关键催化活性位点；探讨影响NOx光催化性能的关键环境因素，揭示NOx在特定环境中的演变规律。本研究将探索NOx的光催化反应机理，深入认识大气环境中催化材料的介入对气态污染物转化的作用机制，为NOx污染减量提供必要的创新技术支持。

氮氧化物（NOx）是导致城市灰霾发生的重要气态污染物之一，伴随着城市机动车及其他燃烧源排放的持续增加，NOx的控制依然为当前大气污染控制的难题。光催化技术是去除开放/半开放空间低浓度NOx的重要方法之一，但该技术面临可见光下低活性与选择性的问题。本项目分别对ABO3型钙钛矿SrTiO3以及Aurivillius型Bi4Ti3O12纳米材料进行氧空位调控以及氧活化性能研究，并研究对NO光催化性能及去除机理的影响。采用Fe3+元素掺杂的方法调控SrTiO3调控氧空位的形成，利用密度泛函理论计算与电子顺磁共振表征氧空位，通过原位漫反射红外光谱研究SrFeTiO表面NOx的吸附及光催化转化机理，揭示活性及选择性提升的关键原因。利用电子顺磁共振、自由基捕获以及密度泛函理论研究Bi4Ti3O12表面沉积不同贵金属(Ag, Pt, Pd)对氧活化性能的影响，揭示关键ROS与光催化选择性之间的内在关联，探讨光催化技术去除气相污染物的环境意义。