Directional Transport in Hierarchically Aligned ZSM-5 Zeolites with High Catalytic Activity

作者：Bo‐Jun Zeng, Si‐Ming Wu, Mingbin Gao, Ge Tian, Liying Wang, Zhiwen Yin, Zhi‐Yi Hu, Wen Zhang, Ganggang Chang, Mao Ye, Christoph Janiak, Osamu Terasaki, Xiaoyu Yang · 发表于：Journal of the American Chemical Society · 年份：2024 · DOI：10.1021/jacs.4c09483 · 被引用次数：25 · 研究领域：Zeolite Catalysis and Synthesis、Catalytic Processes in Materials Science、Catalysis and Hydrodesulfurization Studies

Zeolites, the most technically important crystalline microporous materials, are indispensable cornerstones of chemical engineering because of their remarkable catalytic properties and adsorption capabilities. Numerous studies have demonstrated that the hierarchical engineering of zeolites can maximize accessible active sites and improve mass transport, which significantly decreases the internal diffusion limits to achieve the desired performance. However, the construction of hierarchical zeolites with ordered alignments and size-controlled substructures in a convenient way is highly challenging. Herein, we develop a facile procedure using two common structure-directing agents, tetrapropylammonium hydroxide (TPAOH) and tetraethylammonium hydroxide (TEAOH), to synthesize hierarchically aligned ZSM-5 (Hie-ZSM-5) crystals with a -axis alignment substructures of controllable size. The control of the substructure size (α) in the range of 10–60 nm and the corresponding similarity ( r = α/β, where β is the size of Hie-ZSM-5) ranging from 0.004 to 0.033 can be tuned by varying the Si/Al ratios (40–120). A systematic investigation of the overall crystallization process, using time-dependent XRD, SEM, TEM, and solid-state magic-angle spinning NMR ( 13 C, 27 Al, 29 Si) methods, enable us to construct a solid mechanism for the generation of Hie-ZSM-5. Most importantly, directional transport in the unique structures of Hie-ZSM-5 efficiently enhances mass diffusion, as well as catalytic act...