新型Sn基沸石分子筛的设计合成及其烷烃脱氢合成烯烃反应催化性能

Non-precious metal catalysts for propane dehydrogenation to propylene are highly desirable from viewpoint of practical application. Their rational design synthesis, functionality-related catalytic mechanism and control of chemo-selectivity to desirable olefin products are challengeable researches with high scientific values. With the purpose to construct new catalytic system useful for dehydrogenation of propane to propylene, this project will be carried out to synthesize Sn-based zeolites with the Sn clusters or sub-nanoparticles well confined within micropores or intracrystals, through controlled reduction of isolated Sn ions in Sn-zeolite framework. The planned researches include the preparation of various Sn-zeolites with the BEA*, MWW, UTL, FAU and MFI topologies and 10 – 14 membered ring pores, Sn clusters formation within zeolite pores, chemical control of the amount and dispersion of active Sn species, investigations into catalytic dehydrogenation properties and reaction mechanism as well as understanding of stability control. It will be focused on the insight into the synergistic effects between zeolite crystalline and pore structures and Sn species. The achievements to be obtained from this project would provide not only new catalytic system for olefin production but also new methods for rational design of metal particle catalysts based on microporous zeolites.

烷烃脱氢制烯烃非贵金属催化剂具有重要的实际应用价值，其理性设计、催化作用机制和目标产物选择性的化学控制是富有挑战性和学术意义的研究课题。本项目拟从含Sn杂原子分子筛出发，通过对高度孤立状态骨架Sn离子的可控化学还原，构筑沸石分子筛孔道以及晶体内限域组装的Sn（亚）纳米或团簇催化中心，构建丙烷无氧催化脱氢高效合成丙烯的新催化体系。研究内容涵盖具有10-14元环孔道的BEA*、MWW、UTL、FAU和MFI等系列含Sn杂原子分子筛的制备、微孔孔道内Sn物种的限域组装、催化中心数目和颗粒分布的化学调控、烷烃催化脱氢性能、催化作用机制和稳定性控制等多个方面。重点研究分子筛晶体和孔道结构与Sn物种的协同匹配对Sn团簇中心的烷烃脱氢催化作用本质影响，为高效合成烯烃提供新的催化体系，同时也为理性合成分子筛负载型金属纳米催化材料提供新思路和指导。

本项目基于杂原子分子筛的设计合成，构筑丙烷无氧脱氢高效合成丙烯催化新体系，研究催化中心的结构、落位以及杂原子分子筛晶体和孔道结构与催化中心的协同催化机理。利用二次晶化策略构筑高载量的杂原子分子筛材料；基于硅锗分子筛的结构柔性和丰富的骨架锗原子，创制一系列孔道和组成可变的杂原子分子筛。在此基础上开展原位还原构筑分子筛限域型金属催化剂，考察其丙烷脱氢催化性能，揭示反应机理，建立催化剂的构效关系，为构建多功能催化体系和研发合成丙烯等烯烃新工艺路线提供新思路。