具有核壳结构特征高效分子筛脱硝催化剂的构建原则

针对我国工业固定源氮氧化物的排放特征，开展相关废气催化治理的基础研究。基于分子筛晶貌调控，通过外包裹、内填充、原位转晶、刻蚀扩孔等策略，制备出一系列具有核壳结构的分子筛型催化剂，探究其选择性催化还原脱硝性能，以及水热稳定性和耐毒能力。采用SAEM、EXAFS、NMR、XPS等表面敏感技术，精确揭示催化剂的等级孔结构、活性组分落位和微区配位环境，重点考察核壳间界面效应及协同催化机制，核壳间多级孔的贯通性及匹配原则；以期实现反应与传质的有效耦合。基于原位红外、程序升温等谱学技术，结合密度泛函、蒙特卡洛、分子动力学等量化计算，探索氮氧化物的吸附、迁移、转化机制，以及催化剂的中毒和再生机理；揭示核壳特征多级/等级孔结构-酸性-活性中心-综合脱硝性能间内在关联，设计并制备出低温活性优异、活性温度窗口宽泛、耐硫/水/热能力强的催化剂，为新型分子筛催化剂的研发和脱硝技术的产业化提供理论基础和技术支撑。

According to the emission characteristic of NOx coming from industrial stationary source in China, the foundational research will be carried out for the exhaust catalytic control. This proposal focuses on the synthesis of zeolites with diverse morphologies including crystalline, sheet, and hollow sphere. Subsequently, the core-shell zeolite is constructed by a strategy of in-situ coverage, nano-casting, crystal transformation, and acid leaching. SCR performances of the as-prepared catalysts as well as their hydrothermal stability and resistance ability towards poisoning are evaluated. Surface sensitive techniques including SAEM, EXAFS, NMR, HRTEM, and XPS are introduced to investigate the hierarchical pore structure, active component location and its local environment. The emphasis is paid on the interface and synergistic effect between core and shell of the zeolite catalyst during catalytic process. The connectivity of hierarchical pore is analyzed and optimized to achieve the best SCR behaviors based on a matching between reaction rate and mass transfer. The mechanisms on the adsorption, transfer, and conversion of NOx as well as those on poisoning and regeneration are studied based on in-situ infrared and temperature programmed techniques, associated with Density Functional Theory calculation & Monte Carlo simulation and Molecule Dynamic study. The correlation among core/shell-liked multilevel/hierarchical pore structure, acidity, active center, SCR performance will be clarified for a better design of the zeolite catalysts with superior low-temperature activity, wide window for good performance, and high resistance to SO2 & water poisonings and thermal treatment for NOx elimination as well as their practical applications.