Seed-assisted synthesis route for hierarchical EUO zeolite and its catalytic performance in m-xylene isomerization

EUO zeolites with one dimensional 10-membered ring channel have extensive catalytic application prospects. How to enhance their diffusion performance while ensuring pore selectivity remains an ongoing challenge. Here, a direct facile synthesis strategy for hierarchical EUO zeolite was developed through a seed-assisted route. Parameter studies reveal that seed quality determines the textural property of objective zeolite. Seed zeolites play a pivotal role in accelerating crystallization and constructing hierarchical pore structure. On basis of the tracking results of crystallization process, a robust formation mechanism was proposed. Surface defects resulting from partial etching of the seed combine with the organic structure-directing agent (OSDA), leading to the generation of numerous nucleation sites that facilitate the formation of primary building units and significantly accelerate the crystallization kinetics. The formation of mesopore is found to initiate by the buildup of dislocations within primary particles, which arises from polycentric crystallization. Compared to conventional EUO zeolite, the obtained hierarchical candidate exhibits a threefold increase in p-xylene diffusion experiment. Furthermore, it demonstrates excellent catalytic stability in the m-xylene isomerization reaction. In summary, this study presents a promising approach to enhance the diffusion properties of EUO zeolite through a straightforward seed-assisted method, highlighting its potential for practical applications in xylene isomerization processes.