钛基SCR催化剂的微结构设计、控制合成及性能调控机理研究

Selective catalytic reduction (SCR) is an effective technology for denitrification of NOx from flue gas. The properties of SCR catalysts is determined by the composition of materials, however, the size and the molecular aggregates of the active component loaded on the carrier is also play an important role on the properties of SCR catalysts. Therefore, in this project, the TiO2 based SCR catalysts were synthesized by hydrothermal process based on the crystal structure characteristics of each component units of SCR catalysts. The SCR catalysts with different size, morphology, special active crystal face, and crystal orientation were obtained by the controlled reaction process and environment. The synthesis technology and formation mechanism of SCR catalysts were developed. The influences of the synergistic effects of the carrier and active component on the crystal growth and the catalytic activity were investigated in detail, and the microcosmic mechanism was discussed. To make clear the control rule of the morphology related factors of the SCR catalytic system on the structure and property of the active centre, the relationship between the morphology of active component and catalytic activity were realized. The nature effects of the active component on the catalytic activity were studied, and the mechanisms of improving catalytic activity were explored. The structure-activity relations of "active component type/TiO2 carrier-controlled synthesis-structure-specific morphology-surface/interface properties-catalytic activity" were established based on the SCR catalytic system to realize the artificial regulation of catalytic activity.

SCR是有效治理NOx污染的重要脱硝技术，决定SCR催化剂性能的不仅是构成材料组成的性质，还要看活性组分在怎样的尺度、以怎样的形式组装成为分子聚集体而负载于载体上。因此，本项目以TiO2为载体选择性的负载不同活性组分，以水热合成为主要方法，通过对反应过程及环境的控制，利用SCR催化剂各组成单元晶体结构本身的特性实现具有不同尺寸、形貌，尤其是具有特定高活性晶面、特定取向的纳米晶SCR催化剂的控制合成，发展SCR催化剂的合成技术及其形成机理。搞清楚SCR催化体系形貌相关因素对活性中心结构和性质的调控规律，认识形貌与催化活性之间的相互关联性。系统研究活性组分与载体协同作用对晶体生长及催化活性影响的微观机制，揭示活性组分催化作用的本质，探求提高催化活性的机理，建立"活性组分种类/TiO2载体-合成控制-结构-特定形貌-表/界面性质-催化活性"之间的构效关系，实现SCR催化剂催化活性的人工调控。

近年来我国NOx污染的范围和程度已相当严重，金属氧化物催化剂是SCR催化剂研究领域最具吸引力的方向。本项目以二氧化钛为载体选择性的负载不同的金属氧化物活性组分，通过对水热反应过程及环境的控制，利用SCR催化剂各组成单元晶体结构本身的特性实现具有不同尺寸、形貌的纳米晶SCR催化剂的控制合成。系统研究活性组分与载体协同作用对晶体生长及催化活性影响的微观机制。建立催化体系“活性组分种类/二氧化钛载体-合成控制-结构-特定形貌-表/界面性质-催化活性”之间的构效关系。通过本项目的实施，合成了不同形貌的纳米TiO2（微球，棒状组装微球，空心微球，羽毛状纳米晶），掌握了不同形貌合成TiO2纳米结构的工艺参数控制，并搞清楚了其在水热条件的形成机理。通过负载不同的活性组分（MnOx，V2O5，WO3和MoO3），系统研究了制备工艺参数、负载量、活性组分种类等因素对TiO2基SCR催化剂催化活性的影响，并初步掌握了工艺过程控制因素与催化活性之间的相关性。本项目所合成SCR催化剂的催化活性在实验室条件下对于NOx的脱除率可达到90%以上。.在本项目的实施过程中，发表学术论文6篇，全部被SCI收录，申请并授权国家发明专利2项，完成研究报告1份。