MCM-22的温和剥离及其衍生分子筛对钴催化费-托合成产物分布的调控机制

将费-托（FT）活性金属与分子筛组装为双功能催化剂，是调控FT合成产物分布、高选择性合成目标液体燃料的有效策略，但由于酸性、孔结构等因素的交互影响，限制了双功能催化剂的优化设计。综合分析MCM-22族分子筛（MCM-22、MCM-36和ITQ-2）及其前驱体MCM-22(P)的相关研究结果，本项目以含聚氧乙烯基的新型季铵盐为溶胀剂，揭示MCM-22(P)的溶胀和剥离机制，解决温和条件下MCM-22(P)完全剥离的难题；借助MCM-22族分子筛结构规整、酸中心来源和分布相同、孔结构和尺寸可调的结构特点，构筑负载Co双功能催化剂，研究其催化FT合成的产物分布规律。采用不同手段研究分子筛及催化剂的结构、织构、酸性等，并与FT反应结果进行关联分析，揭示双功能催化剂中酸性、孔尺寸、钴物种分布及三者之间可能的协同效应影响FT合成产物分布的作用机制，为进一步优化设计高效FT合成双功能催化剂提供理论指导。

Combinating of Fischer-Tropsch (FT) active metals with micro-meso hierarchical zeolites to obtain a bifunctional catalyst is an effective strategy for tuning the product distribution and synthesizing liquid fuel with high selectivity through one-step process. However, the coupling of the acidic properties, porous structure, and the distribution of FT active metals hinders the further optimal design of a higher performance bifunctional catalyst for FT synthesis. Based on the comprehensive analysis of the structural properties of MCM-22, MCM-36, ITQ-2, and their layered precursor MCM-22(P), herein, we proposed that by using the MCM-22(P) as a matrix, novel quaternary ammonium salt with polyoxyethylene group chain and long-chain alkyl group as a swelling agents, the hydrogen bond between the layers of the zeolite will be removed, and overcome the problem of delamination of the layered zeolite under mild conditions. Consequently, the MCM-22, MCM-36, and ITQ-2 with defined components, identical source and distribution of acdic sites, and adjustable pore size can be obtained, and the FT bifunctional catalyst models will be designed through combinating the cobalt with the synthesized zeolites. The product distribution of FT synthesis was quantitatively correlated with the structure, texture, component of the surface species, acidity, and the distribution of cobalt species of the catalysts, which are characterized by N2 adsorption-desorption at low temperature, XRD, NH3-TPD, pyridine IR, TEM, XPS, and TG-DSC techniques. The influencing mechanism of the acidity, pore size, distribution of cobalt species, and the synergistic effect of the three factors on the FT product distribution will be determined, which will provide the theoretical direction for development of a high-performance FT bifunctional catalyst for one-step selectively synthesizing the desired liquid fuel.