Revealing the Crucial Roles of Pore Interconnectivity between Zeolitic and Nonzeolitic Components in Enhancing Diffusion and Catalytic Efficiency of Industrial Zeolite-Based Catalysts
Yipu Xu, Peng Peng, Hanlin Wang, Hao Xiong, Zhaochao Xu, Xiao Chen, Yanpeng Li, Anmin Zheng, Yingxu Wei, Zifeng Yan, Shutao Xu, Zhongmin Liu
Abstract
One of the utmost targets for catalysis research is to meet social needs in a profitable manner. Zeolitic and “nonzeolitic components” (such as silica, alumina, amorphous aluminosilicate, clay, etc.), as indispensable constituents of an industrial catalyst, both actively participate in industrial processes like polyolefin catalytic cracking and residue fluid catalytic cracking. Yet, the main research activities focus mainly on the diffusion behaviors of a single zeolitic or nonzeolitic component. In this work, the pore interconnectivity between zeolitic and nonzeolitic components to better ensure the diffusion and migration of reaction intermediate products in between was systematically studied by adopting a series of ZSM-5@meso-SiO 2 core–shell mesostructures as models to mimic industrially applied multicomponent zeolite-based catalysts with varying pore interconnectivities between the zeolitic (ZSM-5) and nonzeolitic components (meso-SiO 2 ). Their distinctive differences in the multiscale diffusion behaviors and structure-performance relationships represent the following three summarized scenarios: (1) micro/mesopore orientation, (2) spatial distribution of components, and (3) micro/mesoporous relative pore sizes thereof. These reveal that a well-connected micro/mesopore network can effectively accelerate interfacial diffusion and fully enhance the catalytic efficiency of the zeolitic component, highlighting the foundational functions of pore interconnectivity between zeolitic and nonzeolitic components in terms of the significance of the free migration of reactant species in between.